Showing papers in "Brain in 1969"

Connexions of the somatic sensory cortex of the rhesus monkey. II. Contralateral cortical connexions.

Abstract: THE current interest in the commissural connexions of the cerebral cortex derives from the work of Sperry (1961), Myers (1962a), Gazzaniga (1966) and others, who have clearly shown that the fore-brain commissures play a significant part in the interhemispheric transfer of learning based upon peripheral sensory cues. A recent investigation by Kaas, Axelrod and' Diamond (1967) indicates that commissural fibres may also be involved in mechanisms more complex than mere transfer, for in their study an auditory memory trace appeared to be kept out of one hemisphere by an active suppression originating in the contralateral hemisphere. The anatomical basis for the transfer of learning and for the more subtle effects shown by Kaas et al. is as yet unclear, but there are reasons for considering that the organization of the pathway joining the two hemispheres is not a simple one. This is particularly so in regard to the primary sensory areas of the cortex, for some subdivisions of these areas receive commissural fibres from more than one area of the opposite side while parts of others neither send nor receive such fibres (Myers, 1962Z>; Choudhury, Whitteridge and Wilson, 1965; Ebner and Myers, 1965; Garey, Jones and Powell, 1968; Jones and Powell, 1968; Pandya and Vignolo, 1968). In the absence of commissural connexions between certain significant parts of the peripheral representation of the primary sensory areas such as the freer parts of the limbs or the periphery of the visual field, it is unlikely that information ultimately concerned in learning is transferred (or withheld from transfer) at this level of cortical function. On the other hand, the parts of the sensory areas which are commissurally connected should be functionally different from those which are not. It seemed worth while, therefore, to extend the study on the somatic sensory cortex of the cat to the monkey not only for the obvious reason of its closer affinity to man, but also because the larger size and clearer boundaries of the architectonic and functional subdivisions of the first somatic sensory area make these individual subdivisions more amenable to investigation .

Creutzfeldt-Jakob Disease

Abstract: Creutzfeldt-Jakob disease (CJD), together with its clinical variants, is the more common of the two subacute human spongiform encephalopathies, the other being kuru. The spongiform encephalopathies are slow infections caused by filterable self-replicating agents, the nature of which is not yet fully elucidated. The human diseases resemble three conditions of animals: scrapie of sheep and goats, transmissible mink encephalopathy, and wasting disease of mule deer and elk.

Regeneration in duchenne muscular dystrophy: a histological and histochemical study

Abstract: It is now well known that regeneration occurs in skeletal muscle and the sequence of events has been studied extensively in the experimental animal both with the light...