Human functional network modulated by focused ultrasonic stimulation of the hippocampus

Motivation: Previous transcranial focused ultrasound (FUS) studies show that FUS modulates the gamma-aminobutyric acid (GABA) levels in the cingulate cortex and increases the functional connectivity to and associated with the FUS targets at cortex. Goal(s): Examine the neuromodulatory effects of FUS on the human hippocampus. Approach: Low-intensity FUS was applied to the left hippocampus of four medically refractory patients. Hippocampal functional connectivity was measured before and after FUS using seed-based correlation. Results: Significantly increased functional connectivity to the left hippocampus was found after FUS. FUS significantly decreased the hippocampal functional connectivity at the left precuneus, and right prefrontal cortex (mPFC) Impact: We presented neuroplastic evidence of functional connectivity change induced by FUS at the human hippocampus. Our results show the re-organization of the functional connectivity with changes within (precunues and medial prefrontal cortex) and beyond typical nodes in the hippocampal network.