Characterising the Network-Specific Effects of Piriform Cortex Stimulation Via SEEG

Characterising the Network-Specific Effects of Piriform Cortex Stimulation Via SEEG With Multimodal Data Integration

The prospective study aims to characterize the network-specific modulatory effects of piriform cortex stimulation in patients undergoing stereotactic EEG for drug-resistant epilepsy. Using multimodal data, it seeks to link stimulation-evoked electrophysiological responses across brain networks with clinical outcomes, to inform targeted neuromodulation therapies.

Study Overview

• Status: Not yet recruiting
• Conditions: Refractory Epilepsy; Neuromodulation
• Intervention / Treatment: Device: SEEG recordings and SPES

Detailed Description

This study employs stereotactic electroencephalography (SEEG) to investigate the network-specific mechanisms of brain modulation induced by electrical stimulation of the piriform cortex. By analyzing high-density intracranial recordings, combined with structural and functional neuroimaging, the research systematically characterizes how focal stimulation differentially engages and reorganizes activity across large-scale neural circuits. The primary focus is to decode the electrophysiological signatures of network engagement-including changes in spectral power, phase synchronization, and information flow-to reveal fundamental principles of targeted neuromodulation in the human brain.

• Study Type: Interventional
• Enrollment (Estimated): 10
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Liankun Ren, MD; Phone Number: 13681576621; Email: renlk2022@outlook.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100053
      • Xuanwu Hospital
      • Contact: Liankun Ren, MD; Phone Number: +86 13681576621; Email: renlk2022@outlook.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• The patients were diagnosed with drug-resistant epilepsy.
• The patients underwent stereoelectroencephalography (SEEG) implantation for pre-surgical evaluation of epilepsy, with at least one electrode target reaching the piriform cortex
• Participants/parents/legal guardian provide informed consent for inclusion

Exclusion Criteria:

• Subjects that experience surgical complications during the implant procedure will be excluded from the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: SEEG recordings and SPES effects; This arm encompasses patients with drug-resistant focal epilepsy who underwent intracranial monitoring via stereotactically implanted depth electrodes (SEEG) as part of their standard presurgical evaluation. During the monitoring period, these patients additionally underwent systematic Single-Pulse Electrical Stimulation (SPES) mapping. SPES was administered according to a standardized clinical protocol, involving the delivery of single, low-intensity electrical pulses to selected electrode contacts-including those located within or adjacent to the piriform cortex-while recording the evoked electrophysiological responses across the implanted SEEG network. The data collected in this arm include continuous intracranial EEG recordings, precise stimulation parameters (location, intensity), and the corresponding electrophysiological responses used to characterize cortico-cortical evoked potentials and network connectivity.

Device: SEEG recordings and SPES; The intervention involves single-pulse electrical stimulation (SPES) applied during stereotactic electroencephalography (SEEG) monitoring. Low-intensity, standardized electrical pulses are delivered to targeted contacts within or near the piriform cortex via implanted depth electrodes, while simultaneous full-bandwidth SEEG recordings capture network-wide electrophysiological responses, allowing characterization of stimulation-evoked brain network activation and modulation patterns.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Seizure Discharge Suppression Rate	Quantified as the percentage reduction in the frequency of spikes and interictal epileptiform discharges (IEDs) during active stimulation compared to the baseline period.	72 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Single-Pulse Stimulation Amplitude:	The minimum current intensity (mA) required to elicit a reproducible response.	72 hours
N1 Component Amplitude and Latency:	Amplitude (μV) and latency (ms) of the primary cortical evoked response (N1 wave).	72 hours
Spatial Distribution of Activation	The extent of cortical activation, assessed by the number of electrode contacts showing significant evoked responses.	72 hours
Effective Connectivity Change：	Alterations in effective connectivity strength (e.g., measured by Granger causality within a 500 ms time window).	72 hours
Phase-Amplitude Coupling Index	Changes in coupling between the phase of low-frequency oscillations and the amplitude of the gamma band (30-80 Hz).	72 hours
Functional Network Reconfiguration	Changes in node centrality metrics (e.g., betweenness centrality, degree centrality) based on graph-theoretical analysis of functional networks.	72 hours
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability]	Adverse Events: Incidence and severity of adverse events specifically associated with piriform cortex stimulation.	72 hours

Collaborators and Investigators

• Sponsor: Xuanwu Hospital, Beijing
• Investigators: Principal Investigator: Liankun Ren, Xuanwu Hospital, Beijing

Study record dates

Study Major Dates

• Study Start (Estimated): December 8, 2025
• Primary Completion (Estimated): January 8, 2027
• Study Completion (Estimated): November 8, 2027

Study Registration Dates

• First Submitted: December 2, 2025
• First Submitted That Met QC Criteria: December 12, 2025
• First Posted (Actual): December 26, 2025

Study Record Updates

• Last Update Posted (Actual): December 26, 2025
• Last Update Submitted That Met QC Criteria: December 12, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Electrical stimulation; Electrophysiology; SEEG; Piriform cortex
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Epilepsy; Drug Resistant Epilepsy
• Other Study ID Numbers: 2025-292-202

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No