Closed-loop control of theta oscillations enhances human hippocampal network connectivity

Area of Science:

• Neuroscience
• Cognitive Neuroscience

Background:

• Theta oscillations are crucial for information flow in cortico-hippocampal networks, essential for memory and cognition.
• Direct causal evidence linking theta oscillations to human network communication is limited.

Purpose of the Study:

• To investigate the causal role of theta oscillations in human cortico-hippocampal network communication.
• To explore the efficacy of closed-loop, phase-synchronized electrical stimulation in modulating neural activity.

Main Methods:

• Utilized a closed-loop, phase-locking algorithm for precise electrical stimulation of neocortical nodes.
• Stimulation was timed to ongoing hippocampal theta rhythms in human neurosurgical patients.
• Compared phase-locked stimulation with control stimulation lacking phase synchrony.

Main Results:

• Repetitive, phase-locked stimulation of the lateral temporal cortex increased hippocampal theta during delivery, indicating neural entrainment.
• Post-stimulation, network connectivity showed persistent increases, evidenced by enhanced theta-phase synchrony and hippocampal evoked responses.
• Control stimulation did not yield significant changes in network connectivity.

Conclusions:

• Theta oscillations play a causal role in routing neural signals across the hippocampal network.
• Phase-synchronized stimulation is a viable method for modulating theta oscillations and hippocampal network function.
• This approach holds promise for therapeutic interventions targeting memory and cognitive behaviors.