COMMENT Targeting hippocampal networks: frequency- and state-dependent effects of transcranial alternating current stimulation

Abstract

Non-invasive brain stimulation is increasingly recognized as a viable therapeutic strategy for neurological and psychiatric disorders. However, its efficacy depends on understanding how stimulation parameters interact with brain state and network dynamics. A recent study by Luo et al. (2025) provides robust intracranial evidence that transcranial alternating current stimulation (tACS) exerts frequency-specific and state-dependent effects on neural oscillations in the hippocampus and amygdala [1].

Using multi-site intracranial recordings from patients undergoing stereo electroencephalography (SEEG), the authors demonstrated that 10 Hz tACS elicits a selective and sustained response in the hippocampus, with pronounced modulation of oscillatory activity. This finding aligns with prior work suggesting that alpha-frequency stimulation plays a role in memory consolidation and cognitive enhancement. In contrast, responses in the amygdala were more variable and less predictable across different frequencies, indicating differential network sensitivity to external stimulation.