In 'colored-hearing' synesthesia, individuals report color experiences when they hear spoken words. If the synesthetic color experience resembles that of normal color perception, one would predict activation of parts of the visual system specialized for such perception, namely the human 'color center', referred to as either V4 or V8. Using functional magnetic resonance imaging (fMRI), we here locate the region activated by speech in synesthetes to area V4/V8 in the left hemisphere, and demonstrate overlap with V4/V8 activation in normal controls in response to color. No activity was detected in areas V1 or V2, suggesting that activity in primary visual cortex is not necessary for such experience. Control subjects showed no activity in V4/V8 when imagining colors in response to spoken words, despite overtraining on word-color associations similar to those spontaneously reported by synesthetes.

This study presents a rare case of developmental prosopagnosia. Structural magnetic resonance imaging (MRI) revealed no overt brain abnormalities. EP's basic visual skills and visual memory were intact, as was his ability to judge age, sex and expression from faces, identify facial parts, and make face/non-face decisions. EP was impaired at recognizing famous and very familiar faces and describing visual images of famous faces. He also displayed an anterograde memory impairment for recently studied faces, and performed poorly on tests of unfamiliar face matching, most notably for chimeric faces. It is suggested that EP may be deficient at encoding configural representations of faces. EP appears to have a "pure" (i.e. specific to faces) prosopagnosia, as he shows normal object recognition from unusual viewpoints, good gestalt completion for objects, but not for faces, normal visual imagery for objects but not for faces, a disruption of the inversion effect for faces but not for houses, and performs within the normal range on tests of within-category discriminations, even with unique exemplars of object categories such as famous buildings.

In this study a temporal titration method to explore the extent to which spatial memory is differentially impaired following right temporal lobectomy was employed. The spatial and non-spatial memory of 19 left and 19 right temporal lobectomy (TL) patients was compared with that of 16 normal controls. The subjects studied an array of 16 toy objects and were subsequently tested for object recall, object recognition and memory for the location of the objects. By systematically varying the retention intervals for each group, it was possible to match all three groups on object recall at sub-ceiling levels. When memory for the position of the objects was assessed at equivalent delays, the right TL group revealed disrupted spatial memory, compared with both left TL and control groups (P < 0.05). MRI was used to quantify the extent of temporal lobe resection in the two groups and a significant correlation between hippocampal removal and both recall of spatial location and object name recall in the right TL group only was shown. These data support the notion of a selective (but not exclusive) spatial memory impairment associated with right temporal lobe damage that is related to the integrity of the hippocampal functioning.

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Schizotypy research has revealed associations between positive schizotypal symptomatology and substance use but has not related substance use to important schizotypal traits such as anhedonia. Users and nonusers of cannabis and alcohol completed the Oxford-Liverpool Inventory of Feelings and Experiences, the Peters Delusion Inventory, and the Hospital Anxiety and Depression Scale. Cannabis users scored significantly higher on Unusual Experiences, a scale measuring positive schizotypal symptomatology. Both cannabis and alcohol usage were associated with significantly lower scores on Introvertive Anhedonia, which represents negative symptomatology. Delusional ideation and delusional conviction were significantly higher in cannabis users, but for delusional conviction this was only true for users who also drank alcohol. Neither anxiety or depression scores were higher in cannabis users, but delusional ideation correlated with both anxiety and depression, thus providing mixed support for the idea of the "happy schizotype." Overall, these results suggest that cannabis and alcohol usage is related to different dimensions of psychosis-proneness that broadly parallel the relationship between substance use and positive and negative schizophrenic symptoms, thus supporting the continuity view of psychosis and the multidimensionality of psychosis-proneness.

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