Introduction to synaptic circuits, Gordon M.Shepherd and Christof Koch membrane properties and neurotransmitter actions, David A.McCormick peripheral ganglia, Paul R.Adams and Christof Koch spinal cord - ventral horn, Robert E.Burke olfactory bulb, Gordon M.Shepherd, and Charles A.Greer retina, Peter Sterling cerebellum, Rodolfo R.Llinas and Kerry D.Walton thalamus, S.Murray Sherman and Christof Koch basal ganglia, Charles J.Wilson olfactory cortex, Lewis B.Haberly hippocampus, Thomas H.Brown and Anthony M.Zador neocortex, Rodney J.Douglas and Kevan A.C.Martin Gordon M.Shepherd. Appendix: Dendretic electrotonus and synaptic integration.

The synaptic organization of the brain

Muscle fatigue is an exercise-induced reduction in maximal voluntary muscle force. It may arise not only because of peripheral changes at the level of the muscle, but also because the central nervous system fails to drive the motoneurons adequately. Evidence for “central” fatigue and the neural mechanisms underlying it are reviewed, together with its terminology and the methods used to reveal it. Much data suggest that voluntary activation of human motoneurons and muscle fibers is suboptimal and thus maximal voluntary force is commonly less than true maximal force. Hence, maximal voluntary strength can often be below true maximal muscle force. The technique of twitch interpolation has helped to reveal the changes in drive to motoneurons during fatigue. Voluntary activation usually diminishes during maximal voluntary isometric tasks, that is central fatigue develops, and motor unit firing rates decline. Transcranial magnetic stimulation over the motor cortex during fatiguing exercise has revealed focal cha...

Spinal and Supraspinal Factors in Human Muscle Fatigue

Unilateral neglect reflects a disturbance in the spatial distribution of directed attention. A review of unilateral neglect syndromes in monkeys and humans suggests that four cerebral regions provide an integrated network for the modulation of directed attention within extrapersonal space. Each component region has a unique functional role that reflects its profile of anatomical connectivity, and each gives rise to a different clinical type of unilateral neglect when damaged. A posterior parietal component provides an internal sensory map and perhaps also a mechanism for modifying the extent of synaptic space devoted to specific portions of the external world; a limbic component in the cingulate gyrus regulates the spatial distribution of motivational valence; a frontal component coordinates the motor programs for exploration, scanning, reaching, and fixating; and a reticular component provides the underlying level of arousal and vigilance. This hypothetical network requires at least three complementary and interacting representations of extrapersonal space: a sensory representation in posterior parietal cortex, a schema for distributing exploratory movements in frontal cortex, and a motivational map in the cingulate cortex. Lesions in only one component of this network yield partial unilateral neglect syndromes, while those that encompass all the components result in profound deficits that transcend the mass effect of the larger lesion. This network approach to the localization of complex functions offers an alternative to more extreme approaches, some of which stress an exclusive concentration of function within individual centers in the brain and others which advocate a more uniform (equipotential or holistic) distribution. In human beings, unilateral neglect syndromes are more frequent and severe after lesions in the right hemisphere. Also, right hemisphere mechanisms appear more effective in the execution of attentional tasks. Furthermore, the attentional functions of the right hemisphere span both hemispaces, while the left hemisphere seems to contain the neural apparatus mostly for contralateral attention. This evidence indicates that the right hemisphere of dextrals has a functional specialization for the distribution of directed attention within extrapersonal space.

A cortical network for directed attention and unilateral neglect.

The basal ganglia: focused selection and inhibition of competing motor programs.

Brain dopamine and the syndromes of Parkinson and Huntington. Clinical, morphological and neurochemical correlations.

Experimental cerebral concussion

Reflex Activity of the Spinal Cord.

The significance of perceptual rivalry resulting from parietal lesion

Among the many clinical forms of polyneuritis, one that affects sensory function alone is sufficiently unusual to attract more than passing attention. In milder forms of infective polyneuritis and in unusual post-diphtheritic cases the clinical phenomena may be predominantly sensory, but evidence of muscular weakness and wasting, particularly in proximal muscle groups, can usually be demonstrated. The so-called diabetic ataxia and alcoholic tabes are also not clear-cut sensory disorders. Herpetic zona is not only confined to a single or related group of nerve roots, but is also regularly accompanied by a motor component, -an anterior poliomyelitis, which is more evident if the involved segments supply the musculature of a limb. The syndrome presented below could be classed among the ataxias, presenting as it does a severe disorganization of movement. From the first the severity of loss of general sensation, beginning at the periphery of the limbs, advancing to include the trunk, and in one case the face, differentiated the clinical picture from that of tabes dorsalis. The coexistence of imyositis\" was not suspected during life. Both patients* were observed in 1939, and though the pathological material has been pre7rved, the part of the clinical record of Case 2 dealIng1ith the last two months of the patient's illness was lost during the war years by the hospital where he was admitted; Sufficient, however, remains from rny personal record of the earlier part of his illness to indicate the identity of the process in the two patients. Case Histories

https://jnnp.bmj.com/content/jnnp/11/2/73.full.pdf

D. Denny-Brown

Papers

Experimental cerebral concussion

Reflex Activity of the Spinal Cord.

The significance of perceptual rivalry resulting from parietal lesion

Primary sensory neuropathy with muscular changes associated with carcinoma.

Fibrillation and fasciculation in voluntary muscle