Biomedical subjects
Publications and source records attributed to R W Hiorns.
Comparisons of mean cell area in the lateral geniculate nucleus between normal and monocularly deprived rhesus monkeys show that late closure at between 3 months and a year of age produces up to 25% shrinkage of cells in the undeprived parvocellular laminae and up to 30% shrinkage in the deprived parvocellular laminae.
The postnatal development of the lateral geniculate nucleus has been studied quantitatively with the electron microscope in normal kittens and in kittens with eyelid closure. The maturation of the synaptic organization of glomeruli in the normal kitten occurs during the period of susceptibility to eyelid closure and is due predominantly to a logarithmic increase in the number of symmetric presynaptic dendritic synapses. In contrast, the proportion of symmetric synapses falls with age in non-glomerular neuropil over this period. Unilateral and bilateral eyelid suture do not interfere with the normal development of the lateral geniculate nucleus.
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The number of neuronal cell bodies has been counted in a narrow strip (30 micrometers) through the depth of the neocortex in several different functional areas (motor, somatic sensory, area 17, frontal, parietal and temporal and in many species (mouse, rat, cat, monkey and man). With the exception of area 17 of the visual cortex in a number of primates the same absolute number (congruent to 110) of neurons has been found in all areas and in all species. In the binocular part of area 17 of the primates there are approximately 2.5 times more neurons. Thus in mammalian evolution the area of the neocortex increases in larger brains but the number of neurons through the depth remains constant, except in area 17 of primates. From these and other findings it is suggested that the intrinsic structure of the neocortex is basically more uniform than has been thought and that differences in cytoarchitecture and function reflect differences in connections.
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A visual search task was administered to eighteen neurosurgical patients and fourteen control subjects on four occasions over a period of six months. Improvement occurred during the first five postoperative weeks but there was evidence of persistent impairment when patient performance was compared to control performance - the comparison makes use of a simple mathematical model.
The patterns of serological polymorphic variety in a group of Oxfordshire populations are related to previously made demographic predictions that the different villages and social classes might be expected to be genetically homogeneous if movement were the main factor determining genetic structure. The predictions are largely fulfilled though there remains a residual pattern of variety which is detectable when all the systems tested are considered together by "genetic distance" examination, and in the case of the geographic variation this pattern reflects the comparative magnitude of the exchanges between the different villages.
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These preliminary results are concerned with the quantitative description of recovery of function and the shape of the recovery curve. Four patients, in whom dylexia was the salient residual symptom of cerebral damage, are described. Individual differences in the pattern of dyslexic error and the time course of recovery are discussed; and recovery--as measured by longitudinal studies of performance in reading tasks--is analysed in terms of a model which takes into account rate of learning and the eventual asymptote. It is suggested that these or analogous techiques may be relevant both for the design of remedial programmes and for problems of prognosis.
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Verbal and performance scores in a standard intelligence test (WAIS) were considered in relation to patterns of hand preference (measured by questionnaire) in a large sample of the general population. Left-handers and mixed-handers did not obtain lower scores than right-handers. Indeed, there was a tendency for subjects who reported that they could use either hand for at least one of the questionnaire tasks to obtain higher I.Q.s. Otherwise, there were no significant differences in I.Q. with the exception of a consistent sex difference, in that men achieved higher scores on both verbal and performance scales.
A taxonomy of error--regarding the visual, grapheme-phoneme, and semantic aspects of reading--is proposed; and it is related to data from developmental studies. A preliminary analysis of recovery curves, based on the performance of two patients in tests of word-reading and object-naming, is also presented. Finally, the problem of extrapolating from test data to functional efficiency is briefly discussed.
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A study has been made of social class distributions and their effects on marital movement in the city of Oxford from 1837 to the present day. The data have been obtained from the marriage registers of nine ecclesiastical parishes which transect the city. There is marked social class heterogeneity according to district, but when the data are combined some striking relationships between occupation and the distributions of marital distance emerge. In general distance decreases and amounts of city endogamy increase almost linearly as one moves from Class I to Class V. There appears to be, however, no very great increase in marital distance in this century as compared with the situation in the last two-thirds of the nineteenth century. Some of the differences between the social classes are due to differences in marital age, but even after this has been taken into account there remains a very statistically significant relationship between class and marital movement.
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