Ethan A. Solomon

Brain stimulation

iTBS induces a suppression-rebound pattern in human cortical excitability
Intermittent theta burst stimulation is now a widely used intervention in neuropsychiatry, but we do not know how it works to change the brain. To test the hypothesis that this is fundamentally an excitatory protocol, we delivered iTBS via intracranial electrodes and recorded subsequent responses to single-pulse stimulation. We found a surprising suppression-rebound pattern -- cortical responses were initially diminished, but gradually increased over time. With collaborators at the University of Iowa, we extended these results to TMS-delivered iTBS.
medRxiv, Sep. 2026 (submitted)

DLPFC stimulation suppresses high-frequency neural activity in the human sgACC
Building off prior studies examining the effects of TMS as measured by intracranial EEG, we tested the specific hypothesis that DLPFC stimulation causes changes in activity of the subgenual anterior cingulate cortex -- a key region involved in the regulation of mood. Using this technique, we showed that DLPFC stimulation transiently suppressess high-frequency activity in the sgACC, suggesting a possible mechanism by which TMS exerts its therapeutic effects in depression.
Brain Stimulation, Nov. 2025

TMS provokes target-dependent intracranial rhythms across human cortical and subcortical sites

In collaboration with colleagues at the University of Iowa, we examined intracranially-recorded responses to single-pulse TMS, teasing apart spectral responses in a wide array of brain regions. We found that spTMS tends to provoke brief but powerful low-frequency responses consistent with non-invasive measures of evoked potentials, but these responses were contingent on the area of stimulation and propagated to deep brain structures. 

Brain Stimulation, May 2024

Cognitive neuroscience

Theta oscillations in human memory

Nora Herweg and I review 25 years of work in human memory and electrophysiology. We offer a framework for understanding why theta oscillations are only variably associated with successful memory, explaining how experimental and analytic choices profoundly influence study findings. 

Trends in Cognitive Sciences, Mar. 2020

Hippocampal theta codes for distances in semantic and temporal spaces

Theta power in the human hippocampus encodes distances in semantic and temporal representational spaces, supporting the notion that the hippocampus generates domain-general "cognitive maps." 

PNAS, Nov. 2019

Dynamic theta networks in the human medial temporal lobe support episodic memory

During episodic memory encoding and retrieval, subregions of the medial temporal lobe -- and subfields of the hippocampus -- demonstrate changes in connectivity, with theta band connections particularly converging on the left entorhinal cortex. 

Current Biology, April 2019

Appointments

• Assistant Professor, Stanford Dept. of Psychiatry (2027-) 

• Instructor, Stanford Dept. of Psychiatry (2025-2027) 

• Postdoc/Resident (research track), Stanford (2022-2025)

• Postdoctoral researcher, Computational Memory Lab, UPenn (1/2019-7/2019)

• Graduate student, PI: Michael Kahana, UPenn (2015-2019)

• Technical Assistant, McGovern Institute, MIT (2012-2013)

• Research Assistant, PI: James DiCarlo, MIT (2009-2012)