Schedule of Events | Symposia

Direct electrical stimulation of the human amygdala enhances recognition memory for objects but not scenes

Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Krista L. Wahlstrom¹ (krista.wahlstrom@utah.edu), Justin M. Campbell¹, Martina K. Hollearn¹, James Swift², Markus Adamek², Lou Blanpain³, Tao Xie², Tyler Davis¹, Peter Brunner², Stephan B. Hamann³, Amir Arain¹, Lawrence N. Eisenman², John D. Rolston⁴, Shervin Rahimpour¹, Joseph R. Manns³, Jon T. Willie², Cory S. Inman¹; ¹University of Utah, ²Washington University School of Medicine, ³Emory University, ⁴Harvard Medical School

Studies suggest the basolateral amygdala (BLA) modulates memory-consolidation processes via interactions with downstream brain regions like the hippocampus. Furthermore, direct electrical stimulation of the BLA in humans enhances declarative memory, and this memory enhancement is marked by oscillatory interactions between the BLA and hippocampus. However, the BLA disproportionately projects to the anterior hippocampus compared to the posterior hippocampus, regions that process non-spatial information about objects and spatial information about scenes, respectively. Nevertheless, the premise that the BLA prioritizes some kinds of memories over others has not been directly tested in humans. In the current study we tested whether brief electrical stimulation of the BLA could differentially enhance declarative memory for specific images of objects and scenes. Epilepsy patients undergoing seizure monitoring via intracranial depth electrodes viewed a series of images of neutral objects and scenes, half of which were immediately followed by brief, low-amplitude electrical stimulation of the BLA. Amygdala stimulation enhanced memory for object images but not scene images when patients were given a recognition-memory test the next day. We also leveraged direct electrical stimulation of the BLA to interrogate the effective connectivity between the amygdala and hippocampus. Using Single Pulse Evoked Potentials (SPEP) we determined how the amygdala interacts with the hippocampus to favor memory for objects compared to scenes. Overall, our results suggest that the BLA initiates memory prioritization processes by preferentially engaging the anterior vs. posterior hippocampus, providing fundamental insight into how BLA projections to hippocampal regions contribute to the neural dynamics of memory prioritization.

Topic Area: LONG-TERM MEMORY: Episodic