Functional neuroanatomy of semantic memory: Recognition of semantic associations

In an effort 60 examine the functional neuroanatomy of semantic memory, we studied the relative cerebral blood flow of eight healthy young subjects us ing O-15-water positron emission tomography (PET). Relative to a visual bas eline control condition, each of four visual matching-to-sample tasks activ ated components of the ventral visual processing stream, including the infe rior occipital and temporal cortices. Contrasting the task with the highest semantic component, a variation on the Pyramids and Palm Trees paradigm, w ith a size discrimination task resulted in focal activation in the anterior inferior temporal lobe, focused in the parahippocampal gyrus. There was ad ditional activation in BA47 of the inferior frontal cortex. These data repl icate and extend previously reported results using similar paradigms, and a re consistent with cognitive neuropsychological models that stress the exec utive role of BA47 in semantic processing tasks. (C) 1999 Academic Press.