The Japanese journal of neuropsychology

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ArticleTitle	The neuropsychology of consciousness
Language	J
AuthorList	Katsuhiko Takeda
Affiliation	Department of Neurology, Mita Hospital, the International University of Health and Welfare
Publication	Japanese Journal of Neuropsychology: 28 (2), 104-112, 2012
Received
Accepted
Abstract	The nature of the relation between neuropsychology and consciousness has become a major issue. I reviewed several human case studies following the cortical lesions. DB has a hemianopia but nevertheless has surprising visual capacities. When questioned about his vision in the left field, DB reports that he sees nothing. When DB was asked to point to locations in the impaired field in which spots of light were turned on briefly, he was surprisingly accurate. This phenomenon has become known as blindsight. One patient with cortical sensory syndrome was able to localize tactile events when forced to point to the stimulated zone with the normal hand, even though the patient does not experience any sensation from that zone. This finding may be a tactual analogue of 'blindsight'. Using functional MRI, tactile stimuli were administered to both hands of healthy subjects and a right tactile extinction patient in our experiment. In the patient simultaneous bilateral stimuli activated the bilateral SI along with the bilateral SII. Our study suggests that activation of SI is insufficient to engender an awareness of sensory stimuli. The dissociation between implicit and explicit memory in amnesic patient is one of striking dissociation in neuropsychological syndrome. This observation was made in studies of preserved motor skill learning and priming effect that included patients with dense amnesia. The nondominant hemisphere performs in a superior fashion on a variety spatial task including copying designs, reading facial expressions. The nondominant hemisphere also has a concept of self and can recognize and identify social relations, pictures of the person in a social relation, pictures of familial members, acquaintances, and belongings.
Keywords	awareness, blindsight, somatosensory extinction, self awareness, cerebral commissurotomy