Effects of left frontal lesions on the selection of context-appropriate meanings

The present study examined the role of the left frontal cortex in strategic aspects of semantic processing. Participants were tested in a semantic pri ming task involving the meaning access of ambiguous and unambiguous words. Patients with left or bilateral frontal lesions failed to develop semantic facilitation of context-appropriate homograph meanings relative to age-matc hed controls and patients with right frontal lesions who produced more faci litation than controls. When the ambiguous words, however, were replaced by unambiguous words, patients with left frontal lesions improved to normal l evels of semantic priming. This pattern of results seems difficult to expla in in terms of a problem to access semantic information per se or to use co ntextual cues. The findings are, however, consistent with a deficit in sele cting context-appropriate meanings in the presence of competing meanings.