# Perceptual Mechanisms of Visual Hallucinations and Illusions in Psychosis

> **NIH NIH R01** · UNIVERSITY OF MINNESOTA · 2020 · $475,822

## Abstract

Project Summary
It is unknown how functions of the brain give rise to psychotic experiences in severe psychopathology.
Consequently, available treatments for psychotic disorders are often marginally effective. Abnormal visual
perception is evident in psychosis (e.g., hallucinations) and noted in people with genetic liability for psychotic
psychopathology (e.g., heightened illusions). Current evidence points to early visual abnormalities in psychosis
that may trigger a cascade of errant neural activity creating distortions in one's visual experience; however, it is
unclear how basic visual and complex guidance functions of the brain separately contribute to visual
misperception in psychotic psychopathology. The overarching goal of the proposed work is to use
sophisticated psychophysical tasks and neuroimaging to a) precisely characterize behavioral and neural
abnormalities in individuals with psychotic disorders during visual perception, b) detail the mechanisms of
visual hallucinations and distortions through the development and testing of a computational model c)
determine if the mechanistic anomalies also mark genetic liability for psychosis.
The goal will be accomplished by studying individuals with psychotic disorders (IPDs), one first-degree
biological sibling of each IPD (SibIPDs), and healthy controls (HCs) demographically similar to the other two
groups. We hypothesize that individuals prone to visual hallucinations exhibit stable neural abnormalities in
early visual cortex (V1, V2) causing errors in the processing of visual elements, and that visual hallucinations
occur in IPDs when contextual influences of more anterior regions (LOC/fusiform, prefrontal cortex) on visual
perception become deviant. Individuals prone to anomalous visual illusions but without a psychotic disorder are
hypothesized to exhibit a stable decrement in high-level influences on visual perception reflected in anomalies
of inter-regional neural synchronization. We will employ contrast discrimination, surround suppression,
attention regulation, and ambiguous object tasks to assess early visual perceptual processes, with and without
contextual modulation, in IPDs, their unaffected biological siblings (SibIPDs), and healthy controls (HCs), to
determine when task performance predicts self-reported visual misperceptions. We will compute cortical
source signals from 248-channel MEG data functionally localized through 7 Tesla (T) fMRI to detail the
location, timing, and synchronization of neural responses during visual perceptual tasks assessing local and
long-range processes in IPDs, SibIPDs, and HCs, as well as determine how neural responses elicited by tasks
predict variation in self-reported visual misperception. We will also characterize visual responses in all tasks
using the Gaussian Scale Mixture model originally published by Schwartz et al (2009) and recently extended in
our work to generalize across multiple scene segmentation cues (Qiu, 2013). We will use this m...

## Key facts

- **NIH application ID:** 9978920
- **Project number:** 5R01MH112583-04
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **Principal Investigator:** Scott R Sponheim
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $475,822
- **Award type:** 5
- **Project period:** 2017-09-21 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9978920

## Citation

> US National Institutes of Health, RePORTER application 9978920, Perceptual Mechanisms of Visual Hallucinations and Illusions in Psychosis (5R01MH112583-04). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9978920. Licensed CC0.

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