Neural mechanisms of semantic memory.

Using previously published functional magnetic resonance imaging work studying object recall as a framework, we describe the spatial and temporal properties of brain activation as one plausible model of visually triggered access to semantic memory. We suggest that interactions between the dorsomedial thalamus and Brodmann area 6 facilitate the setting of object search criteria and perhaps drive the search. The pulvinar nucleus of the thalamus, in concert with ventral temporal and occipital cortical regions, become active later, perhaps when the criteria are met or the target object is identified.