Anatomic Constraints on Cognitive Theories of Category Specificity

• Published in: NeuroImage (Orlando, Fla.) Vol. 15; no. 3; pp. 675 - 685
• Main Authors: Devlin, J.T., Moore, C.J., Mummery, C.J., Gorno-Tempini, M.L., Phillips, J.A., Noppeney, U., Frackowiak, R.S.J., Friston, K.J., Price, C.J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2002
• Subjects: Adult; Attention - physiology; Brain Mapping; category specificity; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; context-specific effects; Discrimination Learning - physiology; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Mental Recall - physiology; Middle Aged; Paired-Associate Learning - physiology; Pattern Recognition, Visual - physiology; PET; Problem Solving - physiology; semantic memory; Semantics; Tomography, Emission-Computed; category specificity; context-specific effects; semantic memory; PET
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1006/nimg.2001.1002

Many cognitive theories of semantic organization stem from reports of patients with selective, category-specific deficits for particular classes of objects (e.g., fruit). The anatomical assumptions underlying the competing claims can be evaluated with functional neuroimaging but the findings to date have been inconsistent and insignificant when standard statistical criteria are adopted. We hypothesized that category differences in functional brain responses might be small and task dependent. To test this hypothesis, we entered data from seven PET studies into a single multifactorial design which crossed category (living vs man-made) with a range of tasks. Reliable category-specific effects were observed but only for word retrieval and semantic decision tasks. Living things activated medial aspects of the anterior temporal poles bilaterally while tools activated a left posterior middle temporal region. These category-by-task interactions provide robust evidence for an anatomical double dissociation according to category and place strong constraints on cognitive theories of the semantic system. Furthermore they reconcile some of the apparent inconsistencies between lesion studies and functional neuroimaging data.