Forms the brain and spinal cord tissue zippy,how to make the business case for your project,making a photobook using ipad - Test Out

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1 Chapter 13 The Spinal Cord & Spinal Nerves Together with brain forms the CNS Together with brain forms the CNS Functions Functions spinal cord reflexes. 2 Spinal Cord Protection By the vertebral column, meninges, cerebrospinal fluid, and vertebral ligaments.
12 Spinal Reflexes Automatic response to change in environment Automatic response to change in environment Integration center for spinal reflexes is gray matter of spinal cord Integration center for spinal reflexes is gray matter of spinal cord Examples Examples somatic reflexes result in skeletal muscle contraction somatic reflexes result in skeletal muscle contraction autonomic (visceral) reflexes involve smooth & cardiac muscle and glands. 25 Brachial Plexus Ventral rami from C5 to T1 Ventral rami from C5 to T1 Supplies shoulder & upper limb Supplies shoulder & upper limb Passes superior to 1st rib & under clavicle Passes superior to 1st rib & under clavicle Axillary n. 31 Dermatomes Damaged regions of the spinal cord can be distinguished by patterns of numbness over a dermatome region Damaged regions of the spinal cord can be distinguished by patterns of numbness over a dermatome region Infusing local anesthetics or cutting roots must be done over 3 adjacent spinal nerves.
21)    HuntstockREFERENCES:George Kraft, director, Multiple Sclerosis Rehabilitation, Research, and Training Center and director, Western Multiple Sclerosis Center, University of Washington, Seattle.
Francois Bethoux, MD, director of rehabilitation services, the Mellen Center for Multiple Sclerosis Treatment and Research, The Cleveland Clinic.
The notochord lies ventral to the ectoderm and INDUCES a thickening of the ectoderm - the NEURAL PLATE. A shallow depression appears in the neural plate as it continues to thicken and this is termed the NEURAL GROOVE. The process of neural plate formation and its infolding to form the neural tube is called NEURULATION. Failure of the rostral pore to close leads to a condition known as ANENCEPHALY where neural tissue is exposed on the skull suface.
If the caudal neuropore fails to close, it leads to malformation and non-fusion of the vertebral arches - a condition known as SPINA BIFIDA. In the cerebellum and cerebral cortices, neuroblasts migrate to the outside of the neural tube, thus in the adult, the grey matter of these areas is peripheral to the white matter.
The dorsal laminae fuse as the plate develops and form the roof of the third and fourth ventricles. Somatic neurones tend to occupy the more peripheral dorsal and ventral postions of the neural tube.
Sensory afferents are derived from neural crest cells and connect to the dorsolateral lamina.
The VENTRAL HORN contains bipolar motor neurones whose axons pass out with the spinal nerve to innervate muscles.
After the rostral neuropore closes, the rostral end of the neural tube develops into 3 swellings or BRAIN VESICLES. The dorsal lamina is infiltrated with blood vessels which supply the CHOROID PLEXUS TISSUE.
In addition, ventrolateral to the rest of the nuclei, another column of grey matter develops. The efferent columns are broken up longitudinally, but the afferent columns remain continous. NB During this migration, the grey matter comes to lie on the cortical (outer surface) with internalisation of the white matter. In carnivores, final differentiation of the cerebellar cortex is not completed until around 10 weeks post-partum. The midbrain lies rostral to the pons and is a very short section of the developing neural tube. The major changes in the midbrain are the formation, from the dorsolateral lamina, of four swellings on the dorsal surface of the brain.
The motor and parasympathetic nuclei of the OCULOMOTOR (III) nerve and the motor nucleus of the TROCHLEAR (IV) nerve are found ventrolateral to the aqueduct. All other fibres relaying information from the spinal cord to higher brain areas and vice versa must pass throught the midbrain. The dorsolateral laminae proliferate and form the THALAMUS (a major relay for inputs to the cerebrum) and the HYPOTHALAMUS (an area controlling homeostatic function).
A ventral outgrowth from the floor of the hypothalamus forms the neural component of the pituitary, the NEUROHYPOPHYSIS or posterior pituitary, which secretes oxytocin and vasopressin (ADH). The OPTIC VESICLES (the eyes in the adult) and the optic (II) nerves appear as bilateral outgrowths.
A dorsal outgrowth forms the PINEAL GLAND (or EPIPHYSIS) which, in response to sympathetic activity during the night, produces the hormone MELATONIN and is involved in circadian and seasonal rhythms. In a similar manner to the development of the cerebellum, two large hollow lateral outgrowths of the mantle layer form the CEREBRUM or CEREBRAL HEMISPHERES. The hemispheres are divided into FRONTAL, PARIETAL, OCCIPITAL and TEMPORAL lobes which derive their names from the overlying cranial bones. The oldest part is the PALEOCORTEX or 'smell' brain that consists of the olfactory bulbs, olfactory tract and the pyriform lobes.
The NEOCORTEX contains areas involved in primary sensory processing and motor control, including a visual area, an auditory area a primary motor area and a primary somatic sensory area. ASSOCIATION FIBRES are involved in coordinating functions between areas of the SAME hemisphere. The AMYGDALA is part of the limbic system that lies deep in the pyriform lobe and connects with the hippocampus caudally.
The SEPTAL NUCLEI are an area of grey matter in the rostral part of the septum pellucidum (the membrane that bridges the gap between the corpus callosum and the fornix). Because of its complex development there are several possible malformations of the developing brain and ventricular system. DEFECTIVE CLOSURE OF THE NEURAL TUBE - i) Spina bifida involves incomplete closure of the vertebral arches and protrusion of spinal cord tissue. An excerpt from the American Academy of Medical Acupuncturea€?a€?Acupuncture is a method of encouraging the body to promote natural healing and to improve functioning. Acupuncture treatments can therefore help the body's internal organs to correct imbalances in their digestion, absorption, and energy production activities, and in the circulation of their energy through the meridians. The modern scientific explanation is that needling the acupuncture points stimulates the nervous system to release chemicals in the muscles, spinal cord, and brain. The improved energy and biochemical balance produced by acupuncture results in stimulating the body's natural healing abilities, and in promoting physical and emotional well-being. Acupuncture is a very old medical art, and there are many approaches to learning and practicing it. While acupuncture is often associated with pain control, in the hands of a well-trained practitioner it has much broader applications. Respiratory disorders: sinusitis, sore throat, bronchitis, asthma, recurrent chest infections.
Neurological and muscular disorders: headaches, facial tics, neck pain, rib neuritis, frozen shoulder, tennis elbow, various forms of tendinitis, low back pain, sciatica, osteoarthritis. Acupuncture is particularly useful in resolving physical problems related to tension and stress and emotional conditions. Because your doctor carefully sterilizes the needles using the same techniques as for surgical instruments, or uses disposable needles, there is no risk of infection from the treatments.
Do not over-exercise, engage in sexual activity, or consume alcoholic beverages within 6 hours before or after the treatment.
Plan your activities so that after the treatment you can get some rest, or at least not have to be working at top performance.
Some insurance companies currently cover acupuncture costs, other companies do not yet recognize the value of acupuncture.
An excerpt from the American Academy of Medical AcupunctureAcupuncture is a method of encouraging the body to promote natural healing and to improve functioning. Cognitive evoked potentials have been used to study a number of mental processes but little work has been on learning. This work examines the hypothesis that there are scalp recorded brain potentials in 99 healthy subjects learning a task.
Observers showed no significant electrical activity after the initial visual evoked potential, which ended at about 200msec. I would like to express sincere gratitude and deep thanks to all persons whose constant support and co-operation made the completion of the work possible. I would like to thank those volunteers who took part in the study for giving so much of their time. I would like to express extreme gratitude and deep thanks to all the staff of the Department of Clinical Neurological Sciences in Particular Professor Fausto Iannoti, head of the department, and our secretaries Miss G. I’m also indebted to my colleagues in the cognitive laboratory, in particular Professor Steven Harnad for the continuous expert advice, guidance, and being a very rich source of information in cognition.
I gratefully acknowledge the financial support of The Government of the Arab Republic of Egypt. I’d like to express my deepest gratitude to my wife, Sherien and my sons Ahmed and Hesham for their practical and emotional support, patient, encouragement and Faith in my study and me. Over all and finally unbounded thanks are to GOD for giving me everything which enabled me to establish this work.
Event Related Potentials were to be recorded before and after learning and these averages compared inter-group and intra-group.
Diamond (1990) asked the leading Berkeley astronomer and Nobel Laureate Charles Townes "Which is more complex, the 100 billion stars in our galaxy or the 100 billion nerve cells in the 3-pound mass within our head?" Townes answered without hesitation, "the brain," "For, after all," Diamond responded "it is only the brain that can interpret our galaxy." And it is only the brain that can interpret its own cognizance.
Men ought to know that from nothing else but the brain come joys, delights, laughter, sports, sorrows, griefs, despondency, and lamentations.
In 1848 in Berlin, Du Bois-Reymond recorded the standing potentials between the surface and the cut end of a nerve.
Spontaneous EEG activity was first discovered in animal studies during the late nineteenth century in Liverpool by Caton (1875) using a Thomson reflecting galvanometer and Du Bois-Reymond’s coated, non-polarisable electrode.
Since then the technology has advanced and clinical applications such as epilepsy diagnosis has been developed. An evoked potential (EP) is the sequence of voltage changes generated in the brain, and in the sense organs and pathways leading to the brain, following the reception of the transient physical stimulus.
Delta wave: Frequency of these waves between 1 Hz to 4 Hz and occurs during deep sleep and is normal in awake infants. Event related potentials (ERPs) studies are an attempt to eliminate unrelated potentials and noise.
The evoked potentials are the electrical responses of the nervous system to motor or sensory stimulation with short latency potentials principally reflecting activity generated in the sensory receptors, a neural afferent pathway and its primary receiving area in the brain to a stimulus. The term-evoked potential is defined as the average of multiple responses; the term-evoked response is defined as the electrical recording following a single stimulus. In order to understand how event related potentials illustrate brain functions, we should understand and know the brain cortical organization and structures (Figure 1.2). The Egyptian papyruses were the first systematic written medical records, and the word brain first appeared in the Edwin Smith (1822-1906) translation of an Egyptian surgical papyrus. Two cerebral hemispheres have the same general appearance, and are incompletely separated by longitudinal cerebral fissure, at the bottom of this fissure they are united together by the corpus callosum.
The right hemisphere is responsible for the simple language comprehension, the perception of spatial relationships, conceptual non-verbal ideas, general thought processes, and concentrates on the whole. Most people are right handed, and almost all of them have left-hemisphere dominance which generally speaking is more analytical, logical, precise and time-sensitive.
Arachnoid: it is a lose membrane covers the brain and separated from the dura mater by the subdural space. Pia mater it is very delicate connective tissue rich in blood vessels and known as the gentle mother. The advanced intellectual functions of the human depend on the activity of the cerebral cortex and interaction of this structure with other portions of the nervous system.
The cerebral cortex was examined by the first microscopists, as early as 1776 and the first recorded structural detail was the stria in the occipital cortex, which was noted by Gennari, and named after him. Figure (1.2) shows side view of the human brain location in relation to the skull, the spinal column and the spinal cord.
Figure (1.4) shows the brain covers starting from outside the Skin, the Skull, and the Meningese.
Plexiform lamina (Molecular or Zonal layer): contains the sparsely scattered horizontal cells (of Cajal), and apart from a dense net of tangentially oriented fibers, derived from pyramidal cells (apical dendrites), Stellate cells (Vertical axons), cells of Martinotti (Centrifugal axons), and afferent fibers, both projection and associational.
Internal Granular lamina: Usually narrow than other layers except layer I, Mainly characterised by the somata of stellate cells, and occasionally small pyramidal cells. Internal Pyramidal (ganglionic) lamina: contains largest pyramidal cell somata and smaller elements of the same type occur. Multiform lamina: contains a considerable range of cell types, most of these cells are small and considered to be modified pyramidal elements, despite the fusiform, triangular, ovoid and other profiles of their somata. Careful examination of the thickness and number of cells in these layers reveal systematic differenceson the basis of these differences brodmann 1909 recognised 52 areas. The afferent fibers to the cortex run radially towards the surface and synapse in Layer one through layer four.
The neurons of the pallium have been described and categorised into different classes; the great majority falling into these cell types. Pyramidal cells named from the shape of their somata, varying from small elements measuring about 10m m across to the giant pyramidal cells (of Betz) measuring up to 70m m or more. Stellate nerve cells: They appear in variable density of distribution in all cortical laminae except lamina I, and they are usually concentrated in greater abundance in lamina II and IV often called granule cells because of their small size and appearance in Nissl-stained material. Horizontal cells (of Cajal) are confined to the plexiform lamina I; they are small, fusiform, and their dendrites spread short distances in two opposite directions in the plexiform layer. Mesocortex has three layers of the neurons in zones next to the allocortex and six layers of the neurons in zones that lie adjacent to isocortex. Corticoid areas include the septal region (deep to the paraterminal gyrus), Substantia innominata, and parts of the amygdaloid complex, these regions at the base of the forbrain and contain simple, poorly differentiated cortex. Neurons collect, process, and relay information by generating electrical signals that are transmitted via the cell axon to synaptic junctions with other cells. Both EPSPs and IPSPs are low-amplitude electrotonic potentials (tonic = tension) that are propagated passively and hence decrementally (their size decreases) along the neuronal cell membrane. The potentials of the brain recorded in an EEG appear in waves ranging from 1 to 40 or more cycles per second (hertz or Hz), with amplitude ranging from -100 to +100 microvolts.
Although one neuron generates too small a signal to be observed at any considerable distance from the nerve cell, hundreds of thousands of them can produce a potential field that is strong enough to be detected at the scalp. Figure (1.6) shows the generation of very small electrical fields by synaptic currents in pyramidal cells. Event related potentials (ERPs) recorded from scalp electrodes have been used widely to study human cognitive processes and their neural substrate. Event-related potentials (ERPs) are small voltage fluctuations resulting from evoked neural activity. We assume that the EP (signal) has known time relationship to the stimulus whereas background brain activity (noise) does not. Clinically, the most useful response is obtained following, stimulation of the sensory modalities for vision audition (Auditory Evoked Potentials. It is possible also record a longer latency ERP to a non-event, such as the omission of an expected stimulus from regular train. Other ERPs may be recorded in association with awaiting an expected stimulus (‘expectancy wave’ or ‘contingent negative variation’, CNV) or when preparing to make a motor response (‘readiness potential’); these are recorded as gradually rising negativities located over the central cortex for 1 or 2s before the relevant event. Figure (1.7) Normal Brainstem Auditory Evoked Potential to stimulation of the right ear, recorded between vertex (CZ), and right ear (A2) top tracing. Figure (1.9) shows the normal Somatosensory Evoked Potential (SEP) to arm stimulation, from top to bottom, Far field recorded between scalp and cephalic reference electrodes, and between scalp and non-cephalic reference electrode. The first waveforms in the visual are the N100 and P100, which represent the physiological action of the visual system. The earliest components of the EP are far field potentials and they reflect activity in the receptors and peripheral relay stations. First of three components in visual discrimination tasks is a posterior N200 wave and has been named ‘selection negativity’ (Czigler, 1995). The evoked potentials that are determined by physical aspects of the stimulus have been labeled, ‘exogenous’, appearing in the first 80 msec of recording. In contrast, Event related potentials (ERP) which occur after 200msec are of considerable scientific interest in this study because of their relationship to cognitive functioning. It is the study of the ERP components that are related to higher cortical functions, and thus have captured the interest of researchers interested in perceptual, cognitive, and motor behavior. 1965 Sutton et al first described P300 and related potentials associated with cognitive function. Posterior scalp distribution with maximum at Pz, monotonous inverse relationship between amplitude and stimulus probability. The P300 wave is a positive peak with latency of approximately 250-800 msec of the human event related potential (ERP) has been typically characterized in terms of latency, amplitude and scalp amplitude distribution.
The latency of P300 increases with the time the subject needs to distinguish the rare stimulus. As well as the attention dependent P300 a passive or ‘novelty’ P300 occurs to infrequent non-target stimuli (Courchesne et al, 1984; Knight, 1984). The amplitude of the P300 has been shown to be inversely proportional to stimulus presentation probability and directly to task complexity (Johnson, 1988). P3 amplitude has been shown to be inversely related to a prior probability, the lower probability, and the higher the P3 amplitude. Figure (1.10) shows an example of the Event Related Potential ERP recorded from mid-frontal site at FZ electrode during a learning task. The P300 has a wide distribution with maximum in parietotemporal areas, unrelated to the specific sensory areas but probably related to the parietotemporal association cortex and subcortical structures such as hippocampus and thalamus. Differences in P3 scalp amplitude distribution have been related to differences in the cognitive processes underlying the generation of these waves (Courchesne et al.
Across time P3 scalp distributions do not change so long as the task and eliciting event category do not change, and the effect of the prior probability and sequential event structure on P3 amplitude are relatively constant across time.
If different P3 scalp amplitude distributions do reflect different cognitive processes, then it is conceivable that changes in P3 amplitude and distribution might be found when subjective notions about an event category are altered.
Mecklinger and Ullsperger (1995) hypothesized that the relationship between P300 amplitude and categorization tasks might be modulated by ease of assignment to category. The P300 name is somewhat misleading since it may occur anywhere between 300msec and 1000msec (Rosler et al 1986). Amplitude and latency of ERP components can be used as indices of the nature and timing of a subject’s cognitive response to stimulus.
P300 latency is age dependent, being longer in children, progressively decreasing until 18 before increasing by 1.25msec per year (Barajas 1991 and Diniz and Fukuda 1997). A large number of clinical studies of the P3 component have demonstrated reduction in P3 amplitude in individuals expressing a wide range of behavioral dysfunction, one of which is memory impairment (Rugg, et al. The ERP thus reflects, with high temporal resolution, the patterns of neuronal activity evoked by a stimulus.
For this reason, ERPs are an ideal methodology for studying the timing aspects of both normal and abnormal cognitive processes. On the other hand, ERP data provide less accurate spatial information than positron emission tomography (PET) or functional magnetic resonance imaging (fMRI), which lack fine temporal resolution.
PET studies provide a consistent set of data for the localization of areas active during learning, although they cannot provide the extraordinary time resolution. Learning probably involves many different parts of the brain and no one has been able to say with any degree of certainty where it occurs (Hilgard et al 1966).
P300 amplitude is proportional to the amount of attentional resource allocated when the stimuli are processed (Polish et al, 1994; Siddle, 1991).
In agreement with Von Restorff effect, memory for events that elicit a large P300 is better than otherwise (Karis et al, 1984 and Fabiani et al, 1986). Generation of the P300 is dependent on an inter-hemispheric interaction in the temporal parietal junction (Yamaguchi and Knight, 1995).
The medial temporal lobe (MTL) consists of the hippocampus, amygdala and parahippocampal gyrus and has been linked to recent event memory.
A MTL P300a occurs to infrequent unattended stimuli but is too early to be mistaken for the P300b. Numerous studies that have employed a task in which items were presented sequentially and subjects were asked to respond if the stimulus was unmatched (incongruent) or matched (congruent) with the preceding items (Barrett, and Rugg, 1989, 1990). It is interesting to know that N400 component, as recorded from the scalp is severely attenuated following unilateral anterior temporal lobectomy (Smith and Halgren, 1988) suggesting that the temporal lobes may have an important role in eliciting N400. The N400 has been hypothesized to represent a construction of a cognitive gestalt that encodes the stimulus and its prior contextual occurrences through associative activation of a neocortical MTL network (Halgren and Smith, 1987).
It is well known that bilateral lesions of the human medial temporal lobes produce severe amnesia for recent events (Scoville and Milner, 1957; Squire, 1982). It has been reported P300 latency to be prolonged in adult patients with mental retardation, in patients with dementia of various causes, in patients with parkinson’s disease, in chronic schizophrenic patients. Patient with temporal lobe epilepsy may have delayed P300 which is independent of seizure manifestation or antiepleptic drugs (Fukai 1990).
Delayed P300 has been reported in patients with AIDS and AIDS-related complex even before psychometric tests could detect cognitive deficits (Ollo et al 1991).
The world of science, like that art or religion, is a world created by the human imagination, but within very strict constraints imposed both by nature and the human brain (Jacob.
Learning is the storage of the information as a function of experience and resulting in a relatively permanent change in personality (including cognitive, affective, attitudinal, behavioral, experiential, and the like) and reflect a changes in performance usually brought about by practice although it may arise from insight or other factors including memory. This is a good reflection of the multitude of components involved in learning and is not within the scope of this treatise to comment on all of them. When we say that the dog in a laboratory Pavlovian conditioning experiment has learned and remembers something about the relation between food and bell, what we mean is just that a new behavior has been conditioned: the dog salivates to the bell, whereas previously it did not.
Learning clearly occurs when the animals are paralyzed, even though no behavioral changes take place at that time. There is one major distinction between types of learning concerning the complexity of the information to be learned.
First one is "Relational" learning, the learning of a relation between two stimuli or between a stimulus and behavior required.
Second is "Nonrelational" learning, only a single stimulus (an environmental event) is involved, and the simplest form of nonrelational learning is "Habituation", we have all experienced this type of learning when frequently occurring nonnoxious stimuli such as household noise decrease to attract our attention.
Language and verbal learning is concerned with the acquisition of human language, similar to sensorimotor learning in the sense that it too uses ‘chaining’, albeit on a verbal level.
Only a small part of information entering the consciousness is stored, concepts and ideas can be stored as words (verbal memory) or non-verbal codes.


For example, every instance of a fish encountered is stored as a featural description (exemplar) in memory a new object is analyzed by the sensory system to create a list of features that allows comparison with stored exemplars.
Rule learning: this is the highest form of learning and as such recruits the most advanced perceptual skill. Perceptual learning refers to such things as recognizing or distinguishing between objects or stimuli in the past from their visual appearance, how they feel, how they smell, or their sounds, each of our sensory systems capable to perceptual learning. Reber, 1965, 1967, & 1969 introduced the term of implicit learning, which was about characterization of how one develops intuitive knowledge about the underlying structure of a complex stimulus environment. Since then a lot of evidence to support the claim that sequence learning may occur without concurrent awareness of sequential structures has been based on dissociation between performance increments in the serial reaction time task and performance in measures of conscious knowledge. Learning comprises three identifiably different dimensions: accumulation of knowledge, sequence of learning and varieties of learning.
Lomo 1966 first reported Use-dependent alteration in synaptic strengthen the rabbit hippocampus, eight years later, the term long term potentiation was used to characterize stimulus frequency dependent changes in population EPSPs and the amplitude latency of population spikes in the rabbit dentate, with and without anesthesia (Bliss and Lomo 1973). Accumulation of knowledge: Learning begins at birth when infant learns to associate feeding with the presence of parents.
Many researchers, especially the psychologists believe that learning sequences consists of three stages at least.
Stimulus input: The relevant stimulus is selectively attended to and other distracting events are ignored. Storage of information: Registered information is encoded into a form that permits practice of the information. Retrieval of information: The final event in learning is the recall and utilization of previously learned material.
Karl Lashley 1920s conduct experiments to study the effects of brain lesions on the learning in rats. Kluver and Bucy (1938) observed in animals that the complete removal of both temporal lobes resulted in a well-delineated syndrome known as the Kluver-Bucy Syndrome, which included a failure to recognize visual stimuli.
In 1954 Scoville described a grave loss of recent memory in human which he had observed as a sequel to bilateral medial temporal-lobe resection in one psychotic patient and one patient with intractable seizures. The postoperative findings in 10 patients point to the importance of the hippocampal region for normal memory function (Scoville, 1957).
Some evidence for this comes from pioneering experiments by Wilder Penfield (Penfield and Perot, 1963). Penfield was able to electrically stimulate areas of the cortex of patients who were awake while undergoing surgery for focal epilepsy. He found that the stimulation of temporal lobes led most of these patients to experience very vivid and realistic images. Penfield assumed that subjects were in fact recalling past events that had happened to them, and proposed that memories are stored at very precise cortical locations (as in computer’s memory), and can be stimulating with a small electrode in contact with that location. Loftus criticized Penfield’s data, on the ground that many of the reported experiences were fantasies and could not possibly be real memories. In fact, Penfield was unable to provide clear evidence that any of the reported experiences were true memories. What Penfield detected were probably not memories themselves, but rather combinations of the basic experiences that make up true memories.
Modern brain researches have established that memories are encoded in the brain via the plasticity of synaptic connections between neurons, with individual memories being stored in parallel across huge numbers of neurons organized into "macrocolumn" in the cerebral cortex (Squire 1987). When two connected neurons are excited at the same time, the synaptic connection between them may grow stronger, leading to facilitation between them. Recognition memory may well depend on interactions involving the hippocampus, inferior temporal neocortex and the amaygdala, and retrieval perhaps more dependent on frontal-thalamic medial thalamic nuclei interaction (Joseph, R. If there is prefrontal cortex dysfunction a variety of behavioral mental disturbances are seen in humans e.g. Three Occipito-temporal areas in the ventral object vision pathway had mostly transient responses to stimuli, indicating their predominant role in perceptual processing, whereas prefrontal areas demonstrated by sustained activity over memory. Visual association areas: regional cerebral blood flow ‘rCBF’ increased over the rest of cuneus, the posterior part of the precuneus, the lingual gyrus, the fusiform gyrus, the occipital gyri, the angular gyrus, and the posterior part of the superior parietal lobule.
Prefrontal cortical regions, especially the cortex lining the superior frontal sulcus and the frontal eye field. Limbic and paralimbic structures: the anterior hippocampal formation (but not the posterior), the anterior cingulate cortex, temporal pole, and anterior sector of insula.
Spinal Cord Nerve cell bodies arranged in horns Nerve pathways cross in the spinal cord – Eg. NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM (CNS) Brain Spinal Cord PERIPHERAL NERVOUS SYSTEM Cranial & Spinal Nerves Somatic -- supplies the skeletal muscles. Organs of the nervous system are divided into Central Nervous System (CNS) Central Nervous System (CNS) Peripheral Nervous System (PNS) Peripheral Nervous. Functional Properties of Neurons Irritability – ability to respond to stimuli Conductivity – ability to transmit an impulse The plasma membrane at rest.
THE NERVOUS SYSTEM Central Nervous System Peripheral Nervous System Autonomic Nervous System Allied Health I. The outer membrane surrounding the spinal cord is the dura mater (from Latin, meaning durable mother). This is done by inserting needles and applying heat or electrical stimulation at very precise acupuncture points. These chemicals will either change the experience of pain, or they will trigger the release of other chemicals and hormones which influence the body's own internal regulating system. Medical acupuncture is the term used to describe acupuncture performed by a doctor trained and licensed in Western medicine who has also had thorough training in acupuncture as a specialty practice.
For complex or long-standing conditions, one or two treatments a week for several months may be recommended. As energy is redirected in the body, internal chemicals and hormones are stimulated and healing begins to take place. Most patients feel only minimal pain as the needles are inserted; some feel no pain at all. In the past 2,000 years, more people have been successfully treated with acupuncture than with all other health modalities combined. Substance abuse (drugs and alcohol) especially in the week prior to treatment, will seriously interfere with the effectiveness of acupuncture treatments. This is important for your doctor to know so that the follow-up treatments can be designed to best help you and your problem.
This may be because the act of learning alters the nervous system and the experiments can not be repeated on the same subject.
The volunteers was asked to observe a series of two hundred different images obeyed the rule for two patterns A and B, which had been generated by computer program and displayed randomly on a screen for 2sec and the screen was blank for 2sec. And by this, in an especial manner, we acquire wisdom and knowledge, see and hear know what are foul and what are fair, what are bad what are good, what are sweet and what are unsavory… And by the same organ we become made and delirious, and fears and terrors assail us… All these things we endure from the brain when it is not healthy…In these ways I am of the opinion that the brain exercises the greatest power in the man - Hippocrates, on the sacred disease (Fourth Century). The ‘action potential’ as we know now he described as a sudden negative variation in response to a stimulus.
The Polish scientist Adolf Beck repeated many of Caton’s experiments and presented the electrical activity of the brain in 1890.
EEG activity has been assumed to represent underlying neural processes and the brain waves are generated by the synchronous electrical activity of literally millions potentials of individual neuron. It is represents electrical activity in those 100 billion nerve cells and is a useful research and clinical technique. This is accomplished by time-locking the recording to the stimulus presentation and taking the average response to many stimuli. The term peak, or wave is defined as the positive (downward) or negative (upward) deflections from the baseline that make up the EP.
The brain basically consists of major parts; the brainstem, the cerebellum, the cerebrum, the diencephalon. The left hemisphere is active in speech, writing, calculation, language comprehension, analytical thought processes, and basically sorts out the parts. While some left-handed people have right hemisphere dominance or mixed left and right dominance which is dreamier, more holistic and more involved with sensory perception and abstract cognition.
It is very essential for musical and mathematical talents and for comprehension and execution of language.
Stellate cells also occur in this layer, including horizontally disposed basket cells, vertically orientated fusiform cells, their dendrites and axons extending far beyond the layer itself. Afferent and efferent fibers run radially, neurons in a radial column tend to respond to different aspects of the name thing e.g.
Projection fibers come from the Thalamus, association fibers from widely dispersed areas, and the third group from several specific subcortical structures outside the Thalamus. The pyramidal cells in layer II, III, and V, serve the major efferent pathway of the cerebral cortex. They are small, of the order of 6 to 10m m in diameter, with a rounded soma drawn out at numerous angles by their richy branching dendrites and a single relatively short axon. They are small and multipolar, with a localised dendritic field and a long axon which runs centrifugally to the plexiform lamina (layer I), producing a few short horizontal collaterals en route.
It is consists of five paralimbic areas which surround the medial and basal parts of the cerebral hemispheres. Cerebral cortex layers and the most frequent types of neo-cortical neurons, connections with each others and afferent fibers (blue). Their ability to perform this complex task is due to the unequal distribution of electrically charged particles on either side of its semi-permeable cell membrane.
Several excitatory as well as inhibitory ionic disturbances can therefore occur simultaneously, or nearly so, in neighboring portions of the post-synaptic cell membrane. To do its job of collecting, processing and distributing information, the cell's membrane potential must be disturbed. An increase in the influx of positively charged cations, such as sodium or calcium, reduces the membrane potential and thus depolarizes a portion of the post-synaptic membrane.
Neurotransmitters are quickly removed from the synaptic cleft, most commonly by re-uptake into the axon terminal that secreted them, although enzymatic destruction of the transmitter molecule terminates the action of some neurotransmitters. The amplitude of the EEG signal strongly depends on how synchronous the activity of the underlying neurons is. The external world is transmitted to the cortex via sense organs and the characteristics of these organs and the transmission pathways are reasonably well understood.
When a group of cells is excited simultaneously, the tiny signals combine to generate one large surface signal. These electrical changes are extracted from scalp recordings by computer averaging epochs (recording periods) of EEG time-locked to repeated occurrences of sensory, cognitive, or motor events.
Averaging is the presentation of a stimulus many times and signals for the duration of interest immediately following are summed before being divided by the number of presentations to give the average EP. Such ERPs have been termed ‘emitted potentials’, since there is no outer event to the trigger them (Picton, 1988). The ERP waveform is normally viewed as a series of components, each of which is a manifestation of the synchronized activity of a population of neurons (Ducan-Johnson and Dochin 1982). P3 latency has been shown to covary with speed of information processing as indexed by reaction times, the faster speed of processing, the earlier P3 latency (Ritter et al. The amplitude increases with rarity of the stimulus and to some extent with stimulus intensity. The characteristics of the wave are different in that it is of shorter latency (250msec), of frontal-central recording sites and habituates rapidly (Polish, 1994).
Visually patients with temporoparietal lesions show a decreased novelty P300 with no target decrement (Yamaguchi and Knight, 1995). Y-axis shows amplitude in Microvolts (m n ), and X-axis shows latency in milliseconds (ms).
That is the subject has been considered to be passive and a consistent responder to the event categories, the event probabilities and the task specified by the experimenter.
The two parameters of P300- latency and amplitude are believed to provide indices of information processing (Johnson et al 1985). Due to their high temporal resolution, ERPs provide unique and important timing information about brain processing. As a result, ERPs represent the natural complement of PET and fMRI to study human cognition. Research will help explore the organization of cognitive processes such as selective attention, memory, language, and learning both in normal In a clinical setting, the temporal resolution of ERPs is useful in identifying at which level along the sensory pathways a lesion is localized. Learning establishes long-term memory during learning (Sqiure and Zol-morgan 1991), and the process involves many brain structures including the frontal lobe.
The interval between stimuli suggests P300 is sensitive to the strength of a decaying memory representation. The latency is associated with the speed of stimuli to class during memory update (Duncan-Johnson, 1981; Magliero, 1984).
Consequently larger amplitude is measured in a memory test to repeat items and to correctly identify old items. This leads to the conclusion that the P300 response is dependent on association cortex with the limbic system, sustaining and updating a model of external envelopment (Donchin, 1979). Bilateral damage to this area causes permanent anterograde global amnesia (Scoville and Milner, 1957; Squire, 1986). In these terms the closure of encoding or contextual integration is active (Heit et al, 1990). Performance in an oddball paradigm is not altered by unilateral anterior temporal lobectomy (Stapleton et al, 1987). A late negative component, peaking around 400 msec, in frontal area is observed and is larger in non-matched items than matched items.
Some evidence for this is seen in the decreased amplitude and duration to repeated stimuli (Smith et al, 1986). Causes of amnesia syndromes include thiamin deficiency, resulting from alcohol abuse or severe malnutrition or malabsorption, head injury post-herpes encephalitis all of that can cause severe damage to the medial aspect of the temporal lobes as well as other damage. P300 amplitude changes have been described in various conditions, including frontal lobe lesion, hyperactive children treated with methylphenidate, increase blood lead levels in children, infantile autism, and schizophrenia. Which we mean any process whereby a person or a machine increases its knowledge or improves its skill.
It refers to stored information produced by learning, and is an abstract term that describes mental states which carry information, while learning describes a transition from our mental state to a second, in which the information is in some way different.
The first is that learning may occur without any concomitant change in behavior; if a CS and US such as a shock are presented to subject administered with drugs that block muscular activity, conditioned responses may perfectly well occur to the conditioned stimulus when the paralytic drug has worn off (Solomon and Turner, 1962). The second problem is that many in cases it can be established that organisms do much more than simply acquire new types of behavior. Concerning this one there are many subtypes the simplest one is the classical conditioning which involves learning specific relations between environmental stimuli, and there are more complex types of relational learning. And the second form of nonrelational learning is "Sensitization" in which an organism learns to increase the vigor of a response after exposure to a noxious or threatening stimulus. Categorical learning process of experiencing various stimuli, recognizing that some of them share important common traits and then grouping them together so that we react to them in similar way. The new object is categorized as a fish if it is more similar to the stored exemplars of fish than exemplars of others categories. We can also recognize surrounding peoples from their faces, movements, voices, and we can recognize their emotional status by recognizing the word they are saying.
He argued that the characterization of the implicit learning is basically by these two critical features. The first, reliable performance increments in serial reaction time tasks have reported subgroups of participants who were not able to verbalize the sequence structure after training or who had not even noticed that there was a structure (Cohen, et al. Hebb pointed out that memories can result from subtle alterations in synapses and these alterations can be widely distributed in the brain. There may be changes in the proportions of nucleotides in RNA during learning, but attempts to extract and transfer these changes (as memory traces) between one organism and another have given inconsistent results and are now disregarded. The first one is Short Term Memory (STM), which roughly means storing a limited amount of information temporarily.
Comprehension is the amount of information that can be captured from environment at any one time. This entails sorting out of complex stimuli and recognition of their meaningful attribute e.g.
Failure to retrieve information may be due to a cause that may have occurred during any of the preceding stages of learning e.g. The studied question was how performance on this task was affected by making a lesion in same part of the rat’s cortex. The removal extended posteriorly along the mesial surface of the temporal lobes for distance of approximately 8 cm.
Rather than being stored in precise locations, what is more likely is memories are stored in a distributed fashion across the cortex, with many different parts of the cortex contributing to a given memory. Each approximately 10 –11 neurons in the brain receive inputs from very many other neurons, and these inputs consists of neurotransmitter molecules that attach themselves on receptor sites on the dendrites of the neuron. The posterior and inferior frontal gyri, the second inferior frontal gyrus and the anterior middle frontal gyrus (Courtney, et al.1997). Receive sensory input ? Gather info by monitoring changes or stimuli from inside & outside body › 2.
Nervous System Functions Directs the functions of all human body systems Directs the functions of all human. PowerPoint ® Lecture Slides prepared by Meg Flemming Austin Community College C H A P T E R 8 The Nervous System.
About this Chapter Anatomy of the central nervous system The spinal cord The brain Brain function. Organization of the Nervous System Structural Classification Structural Classification Functional classification Functional classification.
Functions of the Nervous System l Sensory –senses stimuli from both within the body and from the external environment l Integrative. The dura, made of a dense fibrous material, forms the dural sac, which surrounds the spinal cord and cauda equina (to be discussed later) and terminates at the level of the second sacral vertebra. It is intended for general informational purposes only and does not address individual circumstances. Such a doctor can use one or the other approach, or a combination of both as the need arises, to treat an illness. Occasionally the original symptoms worsen for a few days, or other general changes in appetite, sleep, bowel or urination patterns, or emotional state may be triggered. These animal patients do not understand or believe in the process that helps them get better. More and more insurance companies are recognizing the value of providing coverage for medical acupuncture services. The images were classed according to the subject’s decision by pressing one of two buttons. Sedgwick for patience, kidness, encouragement, resignation at time, providing continuos helpful advice, and despite many horrendous personal problems. He found that a spontaneous occipital oscillation disappeared with light stimulation, but not with noise.
By recording an EEG with certain stimuli or tasks it is tempting to speculate a cause and effect relationship. Evoked potentials (EPs) developed from the electroencephalograph (EEG) that is used to record electrical brain activity.
Only events that occur time and time again at the same point in the recording will actually show up in the final average. Sensitive amplifying equipment and the use of averaging technique (Dawson 1954) are required to detect these potentials, which are picked up at a considerable distance from the generator source, and have to be discriminated from other, usually much larger, potentials of physiological and environmental origin with which they are intermixed. The term component is defined as an individual contribution to the potential such as low-frequency component or late component. All our conscious living such as thinking, memory, movement, consciousness, language, sensory perception, and emotion depend on the largest and complex part which is the cerebrum. Each hemisphere has three surfaces lateral surface (convex), medial surface (flat), and inferior surface (very irregular). The both sides of the brain are actively involved while anyone performing thought processes (Bryden, 1982). Higher cognitive function, and many complex motor activities depend on the cortex, and it is responsible for the perception and conscious understanding of all sensations, and it is a site in which any modality of sensation can be integrated with others.
It is not always well demarcated from the subjacent cortical zone of fibers approaching or departing from the cortex itself.
These include the locus ceruleus (origin of noradrenergic fibers), the raphe nuclei of the brain stem (origin of serotonergic projections), and the basal nucleus of Meynert in the basal telencephalon (origin of cholinergic projections). Both temporal and spatial summation of excitatory and inhibitory post-synaptic potentials occurs. All of these chemicals (and more) are contained in both the extracellular fluid surrounding each neuron, and intercellular fluids (cytosol) of neurons, and both contain high concentrations of compounds, called electrolytes, that in solution, conduct an electric current and are decomposed by it into atoms called ions capable of carrying positive or negative electrical charges. In humans, and other mammals, this is most commonly instigated or "stimulated" by the release of a chemical transmitter substance from an axon terminal. A more complex process involves the activation of G-proteins that may open ionic gates directly or stimulate the synthesis of a second messenger chemical (the neurotransmitter is the first) in the cytoplasm of the cell. The most common second messenger, cyclic AMP, is also very rapidly destroyed enzymatically.
However, what happens once the sensory activity reaches the cortex is still poorly understood. Only if thousand of cells simultaneously their small voltage can the signals become large enough to be seen at the surface of the scalp. The spontaneous background EEG fluctuations, which are random relative to the stimuli, are averaged out, leaving the event-related brain potentials. Following these are the early cortical evoked responses, which appear to be generated in the primary receiving areas of the brain.
Secondly an anterior positivity to task related stimuli occurs around 200 msec its behavior is to increase to correctly recognized stimuli. In general, scientists believe that learning involves an alteration in the functional properties of neurons and synapses (Ciesielski and French 1992).
This is a late wave positivity that occurs with a variety of stimuli in many experimental conditions.


Different generators of cortical circuits are engaged in target or novelty P300 generation. The black vertical dotted line marks the point of stimulus onset, and the horizontal black dotted line represents the baseline. These views of P3 waves and their underlying cognitive processes do not take into account the dynamic nature of human information processing, a given event may later generate notions about past as well as future events. Mental operations, such as those involved in perception, selective attention, language processing, and memory, proceed over time ranges in the order of tens or hundreds of milliseconds.
Whereas PET and fMRI can localize regions of activation during a given mental task, event related potentials ERPs can help in defining the time course of these activations.
Visual ERPs help the early diagnosis of multiple sclerosis before any structural abnormality is detected. The Von Restorff effect can be described briefly as an increased recall probability for an item which different from others in an obvious way (e.g. At short inter stimuli intervals only rare targets need updating upon representation as frequent event are likely to occur while their previous image is still held in working memory.
Older studies also show this increase with the degree of confidence with which the decision is made (Squire et al, 1975a and 1975b; Paul and Sutton, 1972).
Brief disruption of the MTL during the first 650msec following stimulus presentation for encoding leads to decreased performance in recall tasks (Halgren et al, 1985).
MTL activity tasks require recent contextual memory, no lexical decision nor sensory discrimination effect can be seen.
It has been proposed that it is represent the associated activation of neural networks basic to stimulus integration (Halgren and Smith, 1987). This repetition sensitivity is lost after left anterior temporal lobectomy (Smith and Halgren, 1989). Severe hypoxia, deep midline tumors and posterior cerebral artery occlusion, Alzheimer’s disease, etc. Memories are what left behind as a result of learning, and we infer the existence of learning from the presence of memories. For instant, in a famous experiment, MacFarlane (1930) trained laboratory rats to run through a maze to obtain food, and found that when the maze was filled with water, the animals continued to take the right path to the food even though they now had to swim to reach it. Although this study concentrates on human learning, organisms possessing fairly well developed neural systems have proved capable of learning.
Nonassociative learning is obtained by repeated exposure to a single stimulus type; associative learning comes from comparison of one stimulus to another (classical conditioning), or comparison of a stimulus to the organism behavior (operant conditioning). In disjunctive categories membership is based on either the presence of one attribute OR the presence of another attribute. Learning visual stimuli recognition involves changes in visual association cortex, by receiving information from lateral geniculate nucleus of the thalamus to the primary visual cortex (Striate cortex).
First is that the implicit learning is an unconscious process, and the second is that it yields abstract knowledge, stimulus environment display and abstract representation of a structure induction lead to implicit knowledge.
Hebb postulated that learning and memory may rise from use-dependent alteration in the strength with which synapses transmit activity (Hebb, 1949).
The second stage is Long Term Memory (LTM), Which means storage of an information permanently, e.g.
Registered (recently received) information enters short-term memory (STM) which is very vulnerable to interference.
Ahissar, and Hochstein 1997, said that the degree of specificity depends on the difficulty of the training conditions. Another experiment about the effect of the brain lesion location and size, He found in the first experiment that the rats given brain lesions before learning took more trials before they could perform the task. Lashley was correct that memories are distributed, and had an important and lasting impact on the study of learning and memory because he led other scientists to consider ways in which memories might be distributed among the many neurons of cerebral cortex. When the input activation reaches a sufficient level, channels are opened which allow ions to be admitted into the neurons. The process of synaptic plasticity has been extensively studied in the hippocampus, where so-called Long-term potentiation (LTP) has been observed. Supporting cells of the CNS Oligodendrocytes Astrocytes: protoplasmic fibrous fibrousMicroglia Ependymal cells. The dura is separated from the vertebrae by the epidural fat in the epidural space (epi, meaning upon).
It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. These should not cause concern, as they are simply indications that the acupuncture is starting to work.
A positive attitude toward wellness may reinforce the effects of the treatment received, just as a negative attitude may hinder the effects of acupuncture or any other treatment.
You can help by insisting that your insurance company offer you reimbursement for medically indicated acupuncture treatments before you accept their policy. In 1929 Berger came up with a systematic description of the human EEG, but scientists at first had difficulty in accepting that his recordings were generated by, or even related to actual brain events. The actual process that scalp electrical potentials represent, is very difficult to establish due to the volume of unrelated and parallel activity that is occurring. The EEG is a medical imaging technique that measures aspects of brain function by analyzing the scalp electrical activity generated by brain structures. 1992 concluded that the left hemisphere sees the trees but not much of the forest, while the right hemisphere sees the forest but not too many of the trees.
The corpus callosum and anterior commissure contain commissural fibers that link corresponding and non-corresponding regions of the two hemispheres.
The outcome of these interactions determines the size of the membrane potential at any point in time. The neurotransmitter diffuses across the synaptic cleft and acts on chemical receptor s on the membrane of a dendrite or the cell body of the post-synaptic neuron. The second messenger then starts a cascade of chemical reactions to open specific ion channels.
An influx of negatively charged anions, such as chloride or an efflux of positively charged cations, such as potassium, increases the local membrane potential and thus hyperpolarizes the postsynaptic membrane. Some second messengers have more persistent effects, thus prolonging the effective action of some neurotransmitters. The transmission of information to the brain involves the flow of ions across the neuronal membrane producing a voltage field around each active neuron. These electrical signals reflect only that activity which is consistently associated with the stimulus processing in a time-locked way. Example include N100 and P100 (both occurring 100msec after presentation of a visual stimulus) which reflect activity of the visual pathways and cortex. Both the selection negativity and the P200 are dependent on the on-line processes that identify relevant visual features. ERP could supply a long sought after physiological correlate of learning but as of yet there has been very little research. It has been linked with many processes and has been classically evoked with the oddball paradigm.
When such alterations occur, the cognitive processes is brought to bear on succeeding events which might differ from those brought to bear on past (earlier) events. Courchesne 1977) have suggested that very novel events elicit frontal P3 waves while less novel events elicit parietal waves. When categories are distinct enough to easily classify stimuli the P300 amplitude reflects the chance of target category.
Learning may be linked to changes in ERP and it has been reported that learning evokes specific changes within the domain of the P300 (Rosler et al 1981).
It reflects the amount of information carried by the stimulus (Looren et al 1988 and Woestenburg et al 1992). Most other functional imaging techniques require the integrating evoked brain activity over many seconds and are thus unable to capture the time sequence of these operations. ERPs are also used to monitor comatose patients to evaluate the functionality of vital centers in the brainstem. The amplitude is related to the overall degree of updating that is required and may be a global closure of encoding (Fiztgerald and Picton, 1981). The generation has been suggested to be a summation of similarly active neural generators each faithful to a specific cognitive processes.
This shows the time course for the MTL encoding, integration and storage contribution to memory. The N400 is larger to non-repeated words or faces and semantically incongruent words at the end of a sentence (Kutas and Hillyard, 1980, Iragui et al, 1996).
Clearly, learning in this case does not merely involve equitation of a set of particular muscle activities conditioned to a set of stimuli, but instead involves acquiring knowledge of spatial lay out of the maze and this knowledge is capable of revealing itself in a variety of different ways. A sequence of two more stimulus-response associations is ‘chained’ together resulting in the motor skill. Abstraction is the process of recognizing that certain stimuli, which share similar attributes, belong in a particular category.
Relational categories do not simply use the presence or absence of attribute but rather a relationship between attributes. Within it individual’s modules of neural analyze information, V3 is devoted to analysis of orientation, area V4 to analysis of colors, and V5 to analysis of movements.
Synapses become strengthened as a result of persistent or repeated correlation between pre-synaptic and post-synaptic neuron activity. STM acts as a buffer which retains new information just long enough for to be transferred, if necessary, to long term memory (LTM). Storage in the STM occurs in a verbal manner irrespective of the sensory modality of the input. They found that the pattern of specificities maps onto the pattern of receptive field selectivities along the visual pathway. The second experiment concluded is that all cortical areas contribute equally in learning and memory. A human form of Kluver-Bussy syndrome is seen sometimes after herpes encephalitis, which damages the temporal lobe selectively.
These ions cause an electrical impulse to be generated, which then travels down the output pathway (the "axon") of the neuron, and which leads to neurotransmitter molecules being released, which can then act on other neurons.
As a result of sending a train of impulses down a microelectrode attached to a part of hippocampus, increase in the strengths of connections are observed, such that a signal from one neuron elicits a much stronger response from another neuron than would normally be the case.
The next layer is the delicate arachnoid mater which is thin and has web-like filaments connecting to the underlying pia mater (arachnoid is Greek for spider). Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site.
It is quite common with the first one or two treatments to have a sensation of deep relaxation or even mild disorientation immediately following the treatment.
The point is smooth (not hollow with cutting edges like a hypodermic needle) and insertion through the skin is not as painful as injections or blood sampling. Acupuncture treatments can be given at the same time other techniques are being used, such as conventional Western medicine,osteopathic or chiropractic adjustments, and homeopathic ornaturopathic prescriptions.
The frontal distribution of the PAL corresponds to metabolic studies by fMRI using a similar task. Berger speculated that the EEG was the manifestation of continuous psychological processes underlying non-localizable mental functions. It is a completely non-invasive procedure that can be applied repeatedly in patients, normal adults, and children with no risks or limitations.
The projection axons of the large pyramidal cells in layer V extend centripetally out of the cortex to reach more or less distant subcortical structures, such as basal nuclei, brainstem nuclei, and the grey matter of the spinal cord. The action of the transmitter chemical on the special protein receptor structures of the post-synaptic membrane opens the gates of "transmitter-dependent" ion channels. The action of second messengers, like that of some neurotransmitters, is usually terminated by rapid enzymatic destruction of the second messenger. The potential difference between the postsynaptic membrane portion and the other parts of the neuronal membrane causes an electrical current to flow along the cell body and dendrites with a return current in the extracellular space. These early, short latency potentials principally reflect activity generated in the afferent pathway and its primary receiving area in the brain. Far field and early cortical evoked potentials only reflect the physical properties of the stimulus and are insensitive to the succeeding cognitive processes. The third component is the N400, which thought to be correlate of stimulus categorization or orientation and is increased by task relevant deviant stimuli. A positive component at 100 msec is called ‘P100’ and a negative deflection at 200 msec is a ‘N200’.
In different modalities it as been reported as Centro-parietal (Pfefferbaum et al, 1980 & 1984), and also a later parietal potential (Courchesne, 1978). The subjects expressed surprise and interest over initial presentations of both very novel and less novel events, but indicated that they soon began to expect them and, finally to ignore them. In other words before an internal category representation is formed the P300 reflects the ease of stimulus category designation.
P300 supplies information about the chronometry of information processing (Kramer and Strayer 1988). ERP recordings, however, provide a millisecond-by-millisecond reflection of evoked brain activity. Donchin (1981) stipulated that P300 is a manifestation of processes that maintain an accurate environmental model, or schema, by continually revising this modal according to most recent useful sensory input. The P300 on the other hand is maximal to repeated words and attended infrequent tones (Smith and Stapleton, 1986; Halgren and Smith, 1987). The definition of these apparently innocuous terms has been a topic of passionate debate by psychologists.
Then these sub-regions of prestriate cortex send the results to the Inferotemporal Cortex, which combines the informations and produces neural activity that corresponds to the perception of particular three-dimensional stimuli. Perruchet and Amorim 1992 conclude that the better way to assess by recognition and free-recall tasks for conscious knowledge about sequential structures. You could memorize fifteen numbers if you studied and rehearsed them for enough time, thus the simple way explaining how the entry of sensory information to the short term memory, then the conversion from short term memory to long term memory has been known as consolidation.
The limited capacity of STM (seven items ± 2) means protection from acquiring too much irrelevant data, which would impede learning.
With easy conditions, learning generalizes across orientation and retinal position, matching the spatial generalization of higher visual areas. Beneath the arachnoid mater is the subarachnoid space, which is filled with cerebrospinal fluid. These pass within a short time, and never require anything more than a bit of rest to overcome. It is important that your physician-acupuncturist know everything that you are doing, so he or she can help you get the most benefit from all your treatments. Our work gives temporal information and association between the potentials and subjects performance. It was not until Adrian and Mattews in 1934 validated his findings that the scientific community took Berger’s work seriously. Both EP and EEG have the advantage of high temporal resolution but poor spatial resolution. The so-called pleomorphic cells are considered as modified pyramidal cells with axon entering the white matter.
In many neurons, the second messenger is cyclic adenosine monophosphate (cyclic AMP) which is rapidly destroyed by the enzyme phosphodiesterase.
These electrical potentials summate in the cortex and extend through the coverings of the brain to the scalp. Many of the cognitive waves are named after their latency when first seen, these names have stuck, e.g.
These findings suggest that (1) successive presentation of novel events should elicit successively less frontally and more parietally maximal P3 waves, and (2) both novel and less novel events should elicit successively smaller P3 waves as subjects come to ignore them.
P300 latency is proportional to the time it takes the subject to evaluate and categorize the stimulus (Horst et al 1980 and Ducan-Johnson 1981).
The difference between two objects may the incredibly subtle yet an adult can classify more than 100.000 items.
Rejected information is not entirely excluded; our information processing system briefly retains and analyses a lot of information we are unaware of which is only passed on to consciousness if it is deemed important. Although controversial, it is widely though the LTP is the basic process whereby the brain stores information. Abbreviated CSF, cerebrospinal fluid bathes the brain and spinal cord as well as the cauda equina, providing protection, nourishment, and a medium for exchange of nutrients and waste. Sclerosis means scarring, and people with MS develop multiple areas of scar tissue in response to the nerve damage. It is proposed that similar studies will be useful in determining the pathophysiology of learning difficulties. This resting membrane potential of the cell comes about because of interplay of several forces including (1) diffusion, (2) electrostatic pressure; and (3) active sodium and calcium pumps. These spontaneous electrical activities are known as electroencephalogram (EEG) and by using the electroencephalographic technique we are able to record these voltage changes. There are also potentials, occurring at longer latency, which appear to influenced by mental processes such as attention to the stimulus or expectation that particular stimulus will occur. These two possibilities are inconsistent with the two views current in literature, which were mentioned above. The innermost membrane surrounding the spinal cord is the vascular pia mater (Latin, meaning tender or devoted mother), which is very closely apposed to the spinal cord. The pyramidal cells are perpendicular to the cortical surface with dendrites long enough to form effective dipoles. These are the potentials, which I am interested in and these are termed "endogenous or event related potentials" (ERPs) to distinguish them from the evoked potentials elicited by external physical events (Halliday 1992). The pia mater has paired specializations called denticulate ligaments, which extend laterally from the surface of the spinal cord and pierce the arachnoid to attach to the inner aspect of the dura mater at 21 pairs of denticulations (dentate means tooth-like - these are tooth-like lateral projections).
This inflammation of the optic nerve may cause blurred vision, loss of color vision, eye pain, or blindness, usually in one eye. The perpendicular spatial organization leads to the summation of the associated currents, especially when these neurons are synchronously activated.
Earlier data suggested that the P300 reflected processes invoked when there is a need for context updating i.e. The denticulate ligaments run longitudinally between the dorsal and ventral roots of the spinal cord and serve to suspend the spinal cord from side to side in the dural sac.
Non-synchronous activity and activity from radially symmetrical stellate cells do not appear in EEG or ERPs. The specificity and dynamics suggest those learning proceeds as a countercurrent along the cortical hierarchy.
The pia continues inferiorly from the end of the spinal cord (at the level of the second lumbar vertebra) as the filum terminale internum. Most of the evidence available at present suggests that the scalp recorded potentials are due to excitatory (depolarising) or inhibitory (hyperpolarising) postsynaptic potentials developed by the cell body and dendrites of pyramidal neurons, rather than axonal action potentials (Allison et al.
Improvement begins at higher generalizing levels, which, in turn, direct harder-condition learning to the subdomain of their lower-level inputs. They conclude that the learning can be effective using only difficult trials, but on condition that learning onset has previously been enabled.
Caudal to the end of the dural sac is a specialization of meninges called the coccygeal ligament (or filum terminale externum) that attaches the meninges, and consequently the spinal cord, to the coccyx. Most people with MS also experience some loss of bladder control, because signals between the brain and bladder are interrupted. MSConfusion, slurred speech, and muscle weakness can be symptoms of MS, but they can also be signs of a stroke. Anyone who suddenly has trouble speaking or moving his or her limbs should be taken to the ER immediately.
It insulates the nerves and helps them send electrical signals that control movement, speech, and other functions. It's most common in regions far from the equator, including Scandinavia and other parts of Northern Europe. These areas get less sunlight, so some researchers believe that vitamin D (the "sunshine vitamin") may be involved.
Research suggests a possible link between vitamin D deficiency and autoimmune disorders, but studies are ongoing.
A spinal tap can check for abnormalities in the fluid that bathes the brain and spinal cord. Use can result in less damage to the brain and spinal cord over time, slowing the progression of disability. Physical therapy can help strengthen muscles, combat stiffness, and get around more easily.
Some people say acupuncture relieves symptoms such as muscle spasms and pain, but research to confirm its value isn't conclusive. Others have reported benefits from injections of bee venom, but a rigorous study, lasting 24 weeks, showed no improvements in disability, fatigue, or the number of MS attacks.
High levels of hormones and proteins may suppress the immune system, reducing the odds of a new attack. Try exercising for 10 minutes at a time, then gradually working your way up to a longer session. Before you begin, check with your doctor about what type of activity and level of intensity would be most appropriate.
While the condition may make it more difficult to get around or complete certain tasks, it doesn't always lead to severe disability.



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