# Probing D2 and 5HT-2A mechanisms in early visual processing in V1

> **NIH NIH F32** · DUKE UNIVERSITY · 2024 · $76,756

## Abstract

PROJECT SUMMARY
Little is known about the modulatory mechanisms contributed by extra-retinal inputs to primary visual cortex
(V1), despite their substantial contribution to visual information processing. While a systematic search across
neuromodulators and their receptors is possible, clinical literature provides an avenue to narrow the search of
potential receptors contributing to these circuits. Schizophrenia (SZ) is one example, where patients exhibit
visual processing deficits. Data suggests these deficits are specific to the magnocellular pathway and not the
parvocellular pathway, with shifted contrast sensitivity for sinusoidal grating stimuli at low but not high spatial
frequencies and reduced BOLD signal in V1. Magnocellular and parvocellular inputs from the lateral
geniculate nucleus of the thalamus are known to show distinct patterns of innervation in V1, but whether there
are differences in modulatory mechanisms between these pathways is unknown. Interestingly, there are
reports of both typical and atypical antipsychotic medications improving visual deficits in SZ patients. It is
known these drugs target a variety of receptors for multiple neuromodulators, providing very little insight into
how these drugs may improve symptoms, but showing us that neuromodulation has a profound impact on early
visual processing. Research in SZ has emphasized the role of dopamine and serotonin systems, as the early
typical antipsychotics show very high affinity for dopamine D2 receptors and drugs with psychedelic effects that
may mimic some positive symptoms of SZ target serotonin 5HT-2A receptors. Anatomical studies have
reported both receptor types in V1, with clear laminar patterns, though precise localization of these receptors
on excitatory or inhibitory neurons remains unknown. Here, we propose to study the role of D2 and 5HT-2A
receptors in magnocellular and parvocellular pathways in layer IVC, and in center-surround mechanisms in
layers II/III. Aim 1 will test whether magnocellular and parvocellular inputs to V1 show differences in response
to activating or blocking dopamine D2 receptors and 5HT-2A receptors. Aim 2a will determine if manipulations
to D2 or 5HT-2A receptors impact center-surround mechanisms as a function of stimulus size. Lastly, Aim 2b
will determine if there is an effect of D2 or 5-HT2A modulation center-surround mechanism as a function of
contrast and orientation.

## Key facts

- **NIH application ID:** 10757896
- **Project number:** 5F32EY034772-02
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** Veronica Galvin
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $76,756
- **Award type:** 5
- **Project period:** 2023-01-01 → 2025-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10757896

## Citation

> US National Institutes of Health, RePORTER application 10757896, Probing D2 and 5HT-2A mechanisms in early visual processing in V1 (5F32EY034772-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10757896. Licensed CC0.

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