Ramping-up hippocampal ripples and their neocortical coupling support human visual short-term memory

Emerging evidence suggests that hippocampus contributes to visual short-term memory (VSTM). However, the role of hippocampal ripple activity—brief high-frequency oscillations associated with memory replay—in supporting VSTM of naturalistic objects remains largely unknown. Here, using intracranial EEG recordings from human participants performing a delayed match-to-sample task, we found that hippocampal ripple rates progressively ramped up during the maintenance period and supported successful VSTM. More critically, hippocampal ripples were temporally coupled with the ripples in the lateral temporal lobe (LTL), and these coupled ripples were associated with the memory reactivation in the LTL. These findings provide direct evidence that hippocampal-neocortical interaction via coupled ripples supports VSTM, extending the hippocampal ripples’ role to short-term mnemonic processes.