BOLD repetition suppression effects are accompanied by EEG power differences during repeat object naming

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Adrian W. Gilmore¹ (adrian.gilmore@nih.gov), Leonardo Claudino¹, Cassandra M. Levesque¹, Anna M. Agron¹, Peter J. Molfese², Vinai Roopchansingh³, Michael D. Rugg⁴, Stephen J. Gotts¹, Alex Martin¹; ¹National Institute of Mental Health/NIH, ²Center for Multimodal Neuroimaging, NIMH/NIH, ³Functional MRI Facility, NIMH/NIH, ⁴Center for Vital Longevity, UT Dallas

Repeatedly processing the same stimulus results in faster and more accurate behavioral responses (a phenomenon term repetition priming) that are accompanied by reductions in neural activity in brain regions relevant to processing that stimulus (repetition suppression). Prior studies using fMRI or EEG have attempted to understand how reductions in neural activity may produce behavioral improvements, but a mechanistic understanding may require both the whole-brain spatial precision offered by fMRI and the temporal precision of EEG. Here, we utilized a simultaneous EEG-fMRI approach to maximize both factors while participants viewed and named common object images. Prior to scanning, 40 participants named 100 objects, and these same 100 images (“repeat stimuli”) were once again named during scanning along with 100 newly presented object images (“novel stimuli”). In-scanner verbal responses were recorded using an MR compatible microphone. Participants named repeat stimuli approximately 100 ms faster than novel stimuli. Analysis of fMRI data identified significant repetition suppression effects in task-responsive regions including left inferior frontal and fusiform cortex. Analysis of scalp EEG data identified prominent repetition-related reductions in ERP voltages over posterior electrodes. Source-estimated EEG data were coregistered with the surface mesh used for the fMRI data, and EEG power was compared for novel and repeat items in fMRI-defined clusters. Both increases and decreases in power were associated with BOLD repetition suppression within these regions, with the former generally preceding the latter. These data highlight the utility of simultaneous EEG-fMRI acquisitions in the study of how repeated experiences modify brain-behavior relationships.

Topic Area: LONG-TERM MEMORY: Priming