Content specific organization of semantics

see same Bookheimer review article quoted above.

The large literature suggests that frontal lobe semantic regions are modality and content independent, but that in the temporal lobe, semantic content is highly organized and spatially segregated. While there are some inconsistencies regarding the location of the categories of the stimuli, regions of focal activity reflect different dimensions of object naming and knowledge including visual features, ans associations with object uses and semantically related objects.

Objects that are manipulable activate brain regions associated with reaching and grasping; objects that move activate visual motion detector areas; and objects that must be discriinated from exemplars of similar objects (like faces) activate visual form recognition areas. Martin and Chao (2001) argue that anterior temporal lobe integrates areas serving increasing uniqueness. Bookheimer argues that the integration of these areas might be served by the anterior inferior frontal gyrus on the left (IFG again).

In general, animals activate lateral fusiform/occipital gyri; tools the left middle temporal gyrus (MTG) or area 21 and medial fusiform gyrus. The areas tend to be continuous rather than discrete on f MRI tests. Caramazza (2000) reviews why.