Brain Vol. 128 No. 2 © Guarantors of Brain 2005; all rights reserved
Editorial
The January issue of Brain introduced a re-designed cover: out went Goudy pt 121 used since February 1994, and in came Gill Sans Medium pt 144; the cover illustration was also more prominent. Changes to the internal design of the journal will follow. Colour printing will be available throughout each issue, and we are dropping charges to authors. However, the editorial office will haul in any unrestrained polychromes, exerting aesthetic judgements, and preventing the pages of Brain from resembling a Neopolitan ice-cream.The present issue has contributions from two individuals whose reputations lie outside the field of neuroscience. Over the last 30 years, A. N. Wilson has written award-winning novels, biographies and social histories. These have no direct connection with medicine but, in 2003, he published Iris Murdoch, as I knew her (Hutchinson, London), and on page 250, Peter Garrard, Lisa Maloney, John Hodges and Karalyn Patterson, writing as physicians and neuroscientists involved in her care (and with the approval of her husband, Professor John Bayley), report a textual comparison of Iris Murdoch's first novel (Under the Net, 1954), one selected from the peak of her distinguished career as a writer (The Sea, The Sea, 1978) and her last novel (Jackson's Dilemma, 1995)—less enthusiastically received but written, as it now transpires, in the throes of early Alzheimer's disease. In scientific terms, this could be considered as a single group ‘n’ of 1 cross-over study but, as A. N. Wilson points out, this design lacks appropriate controls. He suggests comparisons with Agatha Christie or P. G. Wodehouse in order to distinguish formulaic from innovative writing, and to correct for the potential confound introduced by Dame Iris's lifelong tendency for lack of coherence and inconsistency in her creative writing, together with an antipathy towards editorial intrusion. However, in the face of rigorous textual analysis, Mr Wilson concedes that—given the preservation of her general syntactical skills but a much reduced lexicon—his repeated contact with the author may have concealed changes in intellect that were apparent to those not routinely in her company, and so able to see the changes as they occurred. John Cornwell is an Affiliated Research Scholar in the Department of History and Philosophy of Science and director of the Science and Human Dimensions project at Jesus College, both in Cambridge. He works on the public understanding of science and medicine. Mr Cornwell is author of The Power to Harm (Viking 1996); and editor of Nature's Imagination (1995), Consciousness and Human Identity (1998) and Explanations (2004)—all published by Oxford University Press. In October 2004, Ray Tallis reviewed recent publications on consciousness as the basis for a critique and lamentation on the present state of neurophilosophy. Now, in ‘Of Existential Intuition, paw relations and vibratiuncles’, John Cornwell reviews Tallis's own highly original trilogy The Hand: A Philosophical Inquiry in Human Being; I Am: A Philosophical Enquiry into First-person Being; and The Knowing Animal: A Philosophical Inquiry into Knowledge and Truth (Edinburgh University Press 2003, 2004) describing a philosophical approach to what it means to be human in context of the contemporary neuroscience.
To be useful, function in the nervous system needs to be phasic. Signals must go on, and then go off. Failure to transmit afferent information is the regular stuff of field defects, anaesthesia, deafness and the like. But, down the years, Brain has also recorded neurological phenomena that represent more complex abnormalities than the mere failure of sensory transmission: perversions, perseverations and misplacements of the information carried by special senses. Latterly, brain imaging has supplemented these descriptions with snapshots of where in the nervous system activation is occurring. The present issue contains three papers that address the complexity of sensory and visual processing. After demonstrating failure to locate vertically aligned targets in the left half field of individuals with neglect due to right hemisphere lesions, Paresh Malhotra and the group of Masud Husain (page 424), test the relative contributions of breakdown in communication between vision and the manual response; impaired memory for the stimulus sequence; and defects of spatial working memory. They conclude that the latter is primarily at fault through damage to the parietal white matter and insula. Sophie Schwartz and colleagues from Geneva and London (page 277) describe an individual with the illusion of persistent touch after brief tactile stimulation, occurring in the context of a meningioma affecting the sensory cortex. Following bilateral stimulation, K.M. failed to switch off the subjective experience of touch, long after the actual stimulus was over, due (so the argument goes) to sustained activity in the contralateral primary somatosensory cortex: specifically, S1 is implicated in mediating conscious somatosensory experience for contralateral parts of the body. In designating this complaint ‘palinaesthesia’, the authors borrow terminology from visual neurology where ‘palinopsia’ is a recognized symptom of posterior right hemisphere lesions (Critchley M. Types of visual perseveration: ‘paliopsia’ and ‘illusory visual spread’. Brain 1951; 74: 267–99; Bender MB, Feldman M, Sobin AJ. Palinopsia. Brain 1968; 91: 321–38). Not mentioned by Head and Holmes in their monumental description of cortical sensory syndromes (Head H, Holmes G. Sensory disturbances from cerebral lesions. Brain 1911; 34: 102–254), the phenomenon of persistent sensory illusion is first discussed in detail by Peter Nathan, Marion Smith and A. W. Cook in their account of sensory patterns in lesions of the posterior columns of the spinal cord and some other afferent pathways (Brain 1986; 109: 1003–41): ‘after-sensations are prolonged.. and may feel as definite as the stimulus itself.. so that the patient is answering ‘yes’ as the examiner is leaving the room... clinicians who are not aware of these disturbances usually think that the patient is showing hysterical features’. Sophie Schwartz and colleagues suggest that a better understanding of neural mechanisms involved in abnormal somatosensory processing and awareness may have important implications for phantom sensation disorders. This interpretation is born out by Judith Hunter, Joel Katz and Karen Davis (page 308) who show that the range and intensity of phantom limb phenomena are not associated with abnormalities of tactile thresholds or spatial discrimination in the periphery, thus diverting attention away from the state—and sensory performance—of the stump towards (presumably) more centrally disordered sensory processing of tonic sensation experienced as phantom pain.
Brain has often published correlations of structure and function built around the analysis of lesions. At first, function was described clinically, and anatomical validation depended on opportunistic neuropathological verification. It was a major step forward when brain imaging was used routinely to reveal the underlying lesion. However, from the early 1950 s, measurement had already supplemented the clinical assessment of function through neurophysiological exploration of normal structures and lesions (Kugelberg E. Facial reflexes. Brain 1952; 75: 385–96). On page 386, Giorgio Cruccu and colleagues from Rome, Oxford, Mainz and Jena bring together these clinical, radiological and electrophysiological disciplines by evaluating 180 individuals with focal brainstem infarction, stratified for clinical deficits, their lesions depicted by three-dimensional probabilistic display, and each tested for early and late blink and masseter responses, and the jaw jerk. Lesions of the ventral and dorsal pons, median pontine tegmentum and dorsal-lateral medulla correlate with specific components and combinations of the blink and masseter reflexes, whereas the jaw jerk lack discrimination. We review Eric Kugelberg's original description of electromyographic recording of brainstem circuits in From the archives.
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