Elsevier

NeuroImage

Volume 10, Issue 1, July 1999, Pages 15-35
NeuroImage

Regular Article
Functional Specialization for Semantic and Phonological Processing in the Left Inferior Prefrontal Cortex

https://doi.org/10.1006/nimg.1999.0441Get rights and content
Under a Creative Commons license
open archive

Abstract

Neuroimaging and neuropsychological studies have implicated left inferior prefrontal cortex (LIPC) in both semantic and phonological processing. In this study, functional magnetic resonance imaging was used to examine whether separate LIPC regions participate in each of these types of processing. Performance of a semantic decision task resulted in extensive LIPC activation compared to a perceptual control task. Phonological processing of words and pseudowords in a syllable-counting task resulted in activation of the dorsal aspect of the left inferior frontal gyrus near the inferior frontal sulcus (BA 44/45) compared to a perceptual control task, with greater activation for nonwords compared to words. In a direct comparison of semantic and phonological tasks, semantic processing preferentially activated the ventral aspect of the left inferior frontal gyrus (BA 47/45). A review of the literature demonstrated a similar distinction between left prefrontal regions involved in semantic processing and phonological/lexical processing. The results suggest that a distinct region in the left inferior frontal cortex is involved in semantic processing, whereas other regions may subserve phonological processes engaged during both semantic and phonological tasks.

Cited by (0)

This work was supported by NIMH and the McDonnell-Pew Program in Cognitive Neuroscience.

2

To whom correspondence should be addressed at Department of Psychology, Jordan Hall, Stanford University, Stanford, CA 94305-2130. E-mail: [email protected].