Do fMRI connectivity abnormalities in epilepsy matter?

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

Johanna M. H. Rau¹ (jmhrau@uchicago.edu), Robert Baudo¹, Daniel Biro¹, Arantzazu San Agustín¹, Shasha Wu¹, Naoum P. Issa¹, Joel L. Voss¹; ¹The University of Chicago

Mesial temporal lobe epilepsy (mTLE) has been associated with hippocampal network dysfunction, such as abnormally low fMRI connectivity of the hippocampus with areas of the default-mode network (DMN). It is unclear, however, whether these network abnormalities reflect irregular brain activity that contributes to mTLE symptoms (i.e., seizures and memory impairment) or, conversely, whether network alterations merely develop as consequences of the disease (e.g., due to epileptic activity and its potential impact on cognition). To address this, we are applying Hippocampal Indirectly Targeted non-invasive Stimulation (HITS) in patients with mTLE. HITS increases hippocampal fMRI connectivity in healthy adults, especially with posterior-medial areas of the DMN. If HITS increases hippocampal network connectivity in mTLE, this will allow us to test whether fMRI network abnormalities contribute causally to mTLE symptoms: will “normalizing” abnormally low hippocampal connectivity via HITS reduce mTLE symptoms, or not? The effects of HITS on fMRI connectivity and episodic memory are measured at baseline and one day after mTLE subjects receive HITS. Seizure activity is tracked one month before through one month after HITS. We anticipate that this design will allow us to determine whether HITS-induced modulations of hippocampal network connectivity are related to reductions of mTLE symptoms. We have obtained pilot data from N=2 participants, indicating that the HITS methods are safe and well-tolerated in mTLE patients, with preliminary evidence for episodic memory improvement in both participants. In this Sketchpad presentation, we will present updated findings and hope to benefit from feedback on our methods and preliminary analyses.

Topic Area: LONG-TERM MEMORY: Episodic