# Neuronal encoding of rapid categorical decisions across primate oculomotor networks

> **NIH NIH F30** · UNIVERSITY OF CHICAGO · 2024 · $53,974

## Abstract

Project Summary
In a professional table tennis rally, the time between successive ping pong ball hits is around 400ms. Within
this timeframe, the players must rapidly categorize the motion and spin of the ball to appropriately guide the
ongoing motion of their paddle to successfully strike the ball. While numerous studies have investigated the
oculomotor system’s role in the visual categorization process, few have done so where the response must be
initiated in advance of relevant sensory information, such as in the aforementioned example. Thus, the
temporal dynamics of sensory modulation of saccadic decisions remain largely unresolved. To identify the
manner in which visual categorization informs ongoing motor plans, I propose recording neural activity from
populations of neurons in the lateral intraparietal area (LIP), frontal eye field (FEF), and superior colliculus (SC)
while monkeys perform a saccade-based motion categorization task in which motor planning always precedes
the identification of the visual stimulus; consequently revealing the temporal evolution of a categorical
judgment with millisecond resolution. Results from prior studies identified neurons in LIP and FEF that
demonstrate categorical tuning, with increased firing rates when stimuli belonging to the preferred category
appear on screen. Additionally, a recent study from our lab demonstrates the causal role of LIP in visual
categorization in which reversible inactivation of LIP leads to significant deficits in categorization accuracy.
However, the task structure utilized by these studies precludes any attempt to uncover the manner in which
categorical signals influence ongoing motor plans, or identify differences in the timing and strength of
categorical encoding between these brain regions. To date, no study has investigated categorical encoding in
SC, thus we will be the first to identify its role in visual categorization. By simultaneously recording from large,
diverse populations of neurons with linear arrays across these interconnected brain regions, the proposed
research will provide critical insight into the temporal dynamics underlying the transformation of sensory
evidence into oculomotor decisions.

## Key facts

- **NIH application ID:** 10760231
- **Project number:** 5F30EY033648-03
- **Recipient organization:** UNIVERSITY OF CHICAGO
- **Principal Investigator:** Ou Zhu
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $53,974
- **Award type:** 5
- **Project period:** 2022-01-15 → 2027-01-14

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10760231

## Citation

> US National Institutes of Health, RePORTER application 10760231, Neuronal encoding of rapid categorical decisions across primate oculomotor networks (5F30EY033648-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10760231. Licensed CC0.

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