The influence of anatomical locus of lesion and of gender-related familiarity factors in category-specific semantic disorders for animals, fruits and vegetables: a review of single-case studies.
According to a recent study conducted on patients with posterior cerebral artery (PCA) infarcts (Capitani et al., 2009), a prevalent impairment of fruit and vegetable knowledge might be due to damage of the left fusiform gyrus, whereas the representation of animals might be disrupted by anterior temporal lesions. To check the influence of gender and anatomical factors in a larger number of patients, a review was made of all the single-case studies of patients who satisfied the following criteria: (a) a prevalent or selective defect in the representation of animals or fruit and vegetable knowledge; (b) the presence of detailed anatomical data, allowing to evaluate if there is a clear distinction between lesions provoking a prevalent defect for animals and for fruits and vegetables. Results showed that both similarities and differences exist between patients showing a selective impairment for animals and for fruits and vegetables. Important lesions of the mesial and inferior areas of the temporal lobes are, indeed, often observed in patients with every kind of category-specific semantic disorder for living entities, but aetiological, anatomical and gender-related familiarity factors determine the prevalent impairment of animals or of fruits and vegetables in these patients. A prevalent impairment of fruits and vegetables is usually observed in men showing a lesion in the territory of the left PCA, encroaching upon the occipital and the infero-mesial aspects of the left temporal lobe, whereas a prevalent impairment of animals is often found in women showing a bilateral lesion of the anterior temporal cortices. The anatomical differences are interpreted in terms of the 'sensori-motor model of semantic knowledge', whereas the gender-related asymmetries are considered as due to social roles related familiarity factors.