# A data-driven framework for mapping transcranial electrical stimulation effects on audiovisual integration and hallucinations

> **NIH NIH F32** · BETH ISRAEL DEACONESS MEDICAL CENTER · 2024 · $73,828

## Abstract

PROJECT SUMMARY
 Hallucinations are a common, distressing symptom of psychosis-spectrum disorders, which can be
resistant to first-line psychiatric treatments. This symptom is also associated with abnormal audiovisual
integration (AVI) in psychosis, which undermines a holistic perceptual experience of reality. Strong evidence
from a causal lesion network mapping study, supported by the functional neuroimaging literature, indicates that
the right superior temporal sulcus (rSTS) plays a causal role in the brain network underlying both auditory and
visual hallucinations. The rSTS is similarly implicated in AVI deficits, suggesting it could be an ideal target for
biomarker-informed treatment approaches. One such approach is transcranial direct current stimulation (tDCS),
a non-invasive brain stimulation method for modulating the electrical activity of a cortical region. High-definition
tDCS (HD-tDCS), a newly developed and refined version of tDCS, makes precise targeting of the rSTS possible.
As lesion network mapping shows that the rSTS is negatively connected to the brain network underlying
hallucinations, a clinical trial led by fellowship sponsor, Dr. Paulo Lizano, aims to reduce rSTS activity by using
cathodal HD-tDCS, which lowers the underlying membrane potential of the stimulated neural region. In the
current research proposal, I will use electroencephalography (EEG) and clinical measures to assess
engagement of rSTS by HD-tDCS and clinical efficacy of this intervention through the following aims. Aim 1 will
determine if neural correlates of AVI are engaged by cathodal HD-tDCS to the rSTS. I will use my expertise
in EEG to extract biomarkers of audiovisual integration from neural responses to repetitive, frequency-modulated
auditory and visual stimuli. I hypothesize that cathodal HD-tDCS, relative to sham, will improve the strength of
these biomarkers, demonstrating improved AVI and successful engagement of the rSTS after a 5-day treatment
and sustained 1 month following treatment. Aim 2 will investigate if cathodal rSTS stimulation, relative to
sham, may provide acute and long-term reduction of hallucinatory experiences. I will employ my clinical
evaluation skills to measure frequency and severity of hallucinations in participants. I hypothesize that cathodal
HD-tDCS, relative to sham, will reduce the frequency and severity of hallucinations in clinician-rated, self-report,
and behavioral measures after a 5-day treatment and sustained at 1-month follow up. During the course of this
fellowship, I will learn how to perform tDCS and learn about other transcranial electrical stimulation techniques
through training provided by Dr. Lizano and Dr. Matcheri Keshavan at Beth Israel Deaconess Medical Center,
supported by a consultant, Dr. Robert Reinhart. I will also learn how to plan, perform, analyze, and publish data
from a clinical trial through supervision and clinical coursework. Training in professional development will further
prepare me for t...

## Key facts

- **NIH application ID:** 10997921
- **Project number:** 1F32MH135669-01A1
- **Recipient organization:** BETH ISRAEL DEACONESS MEDICAL CENTER
- **Principal Investigator:** Rebekah Lyn Trotti
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $73,828
- **Award type:** 1
- **Project period:** 2024-06-10 → 2026-06-09

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10997921

## Citation

> US National Institutes of Health, RePORTER application 10997921, A data-driven framework for mapping transcranial electrical stimulation effects on audiovisual integration and hallucinations (1F32MH135669-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10997921. Licensed CC0.

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