Beta modulation reflects name retrieval in the human anterior temporal lobe: an intracranial recording study

Naming people, places, and things is a fundamental human ability that is often impaired in patients with language-dominant anterior temporal lobe (ATL) dysfunction or ATL resection as part of epilepsy treatment. Convergent lines of evidence point to the importance of the ATL in name retrieval. The physiologic mechanisms that mediate name retrieval in the ATL, however, are not well understood. The purpose of this study was to characterize the electrophysiologic responses of the human ATL during overt cued naming of famous people and objects. Eight neurosurgical patients with suspected temporal lobe epilepsy who underwent implantation of intracranial electrodes for seizure focus localization were the subjects of this study. Specialized coverage of the ATL was achieved in each subject. The subjects named pictures of U.S. presidents and images of common hand-held tools. Event-related band power was measured for each ATL recording site. Both the left and right ATL demonstrated robust and focal increases in beta-band (14-30 Hz) power during person and tool naming. The onset of this response typically occurred at 400 ms but sometimes as early as 200 ms. Visual naming of famous people and tools is associated with robust and localized modulation of the beta band in both the left and right ATL. Measurement of visual naming responses may provide the groundwork for future mapping modalities to localize eloquent cortex in the ATL.