# Neurocomputational Mechanisms of Auditory Hallucinations

> **NIH NIH R21** · YALE UNIVERSITY · 2020 · $220,500

## Abstract

Hallucinations, percepts with out external stimulus, can be a very distressing feature of schizophreniform
psychotic illnesses. They are trypically with D2 dopamine receptor blocking drugs. However up to 30% of
patients may experiences residual hallucinations despite adequate dosing and those that do are at higher risk
of harm to themselves and others. We propose to address this unmet clinical need through computational
psychiatry. We have devised a task that can engender hallucinations in the laboratory. Our work thus far
suggests that individuals prone to hallucinations in their everyday lives are signioficantly more susceptible to
the lab effect. Our computational analyses of participant behavior reveal that people who hear voices in the
context of a psychotic illness do so because they develop strong perceptual beliefs and those beliefs are
resistant to updating. In our brain imaging work, perceptual beliefs are associated with insula hyperactivity and
poor belief updating is associated with a dearth of cerebellar activity. We would like to develop these
observations into biomarkers to better guide individuals toward particular treatment approaches and to design
improved treatments that target underlying deficits. Here we propose the first step in that process; direct,
causal, hypothetico-deductive, tests of the relationships between computational processes, brain activity and
task behavior. We will characterize the impact of transcranial magnetic stimulation (compared to sham
stimulation) on the perfomance of hallucinating patients on our lab-based hallucination task. Two specific aims
are proposed: Specific Aim 1 will target the link between insula responses and strong prior beliefs. We predict
that by inactivating the insula with inhibitory TMS we will reduce the patients’ proclivity towards task induced
hallucinations. Specific Aim 2 will address the role of the cerebellum in belief updating. By boosting cerebellar
engagement with theta-burst stimulation, we aim to augment the ability of hallucinating patients to detect
changes in the task contingencies and update their priors accordingly. Each aim will be accompanied by
control measures that will confirm target engagement. We believe that priors are driving the experience of
hallucinations in our task, and outside of the lab. If we are correct, the data that we gather will be the first step
towards task and computational model-based development of new treatments, as well as diversion of patients
towards those treatmenst based on computational parameters. However, even if we are wrong, we will learn
that the strong prior model is lacking and that we should pursue other explanations for hallucinations.

## Key facts

- **NIH application ID:** 9829581
- **Project number:** 5R21MH116258-02
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** PHILIP Robert CORLETT
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $220,500
- **Award type:** 5
- **Project period:** 2018-12-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9829581

## Citation

> US National Institutes of Health, RePORTER application 9829581, Neurocomputational Mechanisms of Auditory Hallucinations (5R21MH116258-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9829581. Licensed CC0.

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