# Neural Control of Interceptive Movements

> **NIH NIH R01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $380,926

## Abstract

PROJECT SUMMARY
A high-velocity eye movement or saccade is typically the first motor action we make to orient to an object of
interest. While the neural mechanisms of saccade generation to stationary targets have been thoroughly
investigated, very little is known about the neural control of interceptive saccades that acquire moving targets.
Current dogma based on studies of saccades to stationary targets states that the visual and motor bursts in the
superior colliculus (SC), a major hub in the oculomotor neuraxis, are represented as Gaussians; that the
population activity is centered at the site encoding the target location and, equivalently, desired saccade
vector; that its width remains invariant across different target locations and saccade vectors; and that these
spatial features emerge from a balance of excitation and inhibition mediated through intrinsic, intra-laminar
connectivity. Fundamentally non-overlapping mechanisms must be involved when the target is moving,
because accurate interception can only occur if target velocity information is incorporated in the saccade
command. We reason that as a moving target’s image streaks across the retina, activity sweeps across the SC
too. We hypothesize that the population activity, which starts as a Gaussian to represent the initial visual
response, becomes skewed as it sweeps across the SC; that the extent to which SC population activity is
modified depends on the intra-laminar connectivity weights, the logarithmic map of visual space in SC, and
target speed; that the altered spatial distribution persists during the peri-movement burst; and that an
appropriate computational algorithm must be able to decode the saccade goal from the skewed population
response. We propose to test these hypotheses using a combination of experimental and computational
approaches. Specific Aim 1 will employ an innovative method for simultaneously recording neural activity of
many SC neurons within a functional layer in nonhuman primates performing oculomotor tasks and compare
the spatiotemporal properties of population activity during saccades to stationary and moving targets (different
speeds and directions). Specific Aim 2 will construct a computational model that simulates population activity
in SC and associated saccades to stationary and moving targets. We will employ a distributed architecture for
the superficial and deeper layers of the SC and a lumped block-diagram circuit for the brainstem burst
generator elements, like that done by Arai and colleagues (Neural Networks, 7:1115-1135, 1994). Collectively,
these projects will provide an in-depth insight into the mechanisms for generation of interceptive saccades and
enable a comparison with mechanisms of saccades to stationary targets.

## Key facts

- **NIH application ID:** 9910402
- **Project number:** 5R01EY022854-07
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Neeraj J Gandhi
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $380,926
- **Award type:** 5
- **Project period:** 2013-05-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9910402

## Citation

> US National Institutes of Health, RePORTER application 9910402, Neural Control of Interceptive Movements (5R01EY022854-07). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9910402. Licensed CC0.

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