Stanford Psychiatry and University of Iowa awarded research grant to optimize methods for measuring brain excitability in depression

We are pleased to announce that Stanford Psychiatry’s Corey Keller, Associate Professor of Psychiatry and Behavioral Sciences, has received a grant from the National Institute of Mental Health to optimize methods for measuring brain excitability in depression. Dr. Keller is joined by co-principal investigator Dr. Aaron Boes at the University of Iowa on this project.

Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression, but clinical responses are highly variable due to a lack of clarity of the underlying neural mechanisms and optimal treatment parameters. Treatment targeting the dorsolateral prefrontal cortex (dlPFC) aims to improve symptoms by restoring impaired prefrontal excitability. However, evidence of impaired excitability in depression and subsequent neural change after rTMS is limited due to the lack of reliable markers of prefrontal excitability that can be measured and tracked during rTMS. There is an urgent need for reliable markers of prefrontal excitability to direct personalized treatment and guide systematic screening of novel protocols.

Early local TMS-evoked potential (EL-TEP) is a short-latency response recorded over the dlPFC stimulation site that has been shown to be altered in depression and correlate with treatment outcome, but has suffered from low signal-to-noise and reliability issues. Using the recently developed TARGET (Targeting with Automated Real-time Guidance for Enhancing TMS-evoked potential), the study team will investigate how adjusting TMS parameters affects neural activity measured with intracranial EEG.

“rTMS shows promise for treatment-resistant depression, but its therapeutic effects are inconsistent due to an inability to reliably measure and optimize its impact on brain excitability,” writes Dr. Keller and Dr. Boes. “By developing TARGET to characterize brain differences in depression and track changes during rTMS, we aim to personalize rTMS treatments and facilitate rapid development of new stimulation protocols, ultimately improving outcomes for the millions suffering from this debilitating condition.”

The overarching goal of Dr. Keller’s team in the Precision Neurotherapeutics Lab is to understand the fundamental principles of human brain plasticity and build trans-diagnostic real-time monitoring platforms for personalized neurotherapeutics. Recent publications related to this work include “Stimulation mapping and whole-brain modeling reveal gradients of excitability and recurrence in cortical networks” published in Nature Communications and “TMS provokes target-dependent intracranial rhythms across human cortical and subcortical sites” published in Brain Stimulation.

More Information

For more details about this project, visit NIH RePORTER.