# Visuomotor Prosthetic for Paralysis

> **NIH NIH UG1** · CALIFORNIA INSTITUTE OF TECHNOLOGY · 2024 · $658,011

## Abstract

The objective of the proposed research is to obtain scientific knowledge of visuomotor transformations
in posterior parietal cortex (PPC) and primary motor cortex (M1) from tetraplegic subjects in a clinical
trial to advance the development of neural prosthetics. We have shown in clinical trials conducted over
the past 6 years that PPC can control neural prosthetics for assisting tetraplegic subjects. Other groups
have concentrated on M1 and likewise find control for neural prosthetics. In our studies of PPC we have
found that besides trajectory signals to move robotic limbs or control computer cursors, there are a
plethora of visuomotor signals that represent intended movements of most of the body, movement
goals, cognitive strategies, and even memory signals. Our central hypothesis is that PPC and M1 will
encode visuomotor parameters in both similar and different ways, and that algorithms can be
developed to leverage those signals from the two areas that are complimentary to improve prosthetic
range and performance. Implants will be made in both M1 and PPC, enabling simultaneous recording in
the same subjects, elevating concerns of comparing data from different labs collected in different
individuals with different implants and different tasks.
This central hypothesis will be tested in two broad aims, for which we have substantial preliminary data.
Aim 1 will examine the control of the body by the two areas. It is hypothesized that M1 will
demonstrate strong specificity for the contralateral limb (implants will be made in the hand knob)
whereas PPC will code movements for most of the body and on both contra and ipsilateral sides by
leveraging its partially mixed encoding of parameters (subaim 1a). Whereas M1 is hypothesized to code
spatial variables exclusively during attempted or imagined actions, it is hypothesized that PPC also
encodes cognitive spatial variables in task appropriate reference frames (subaim 1b). In subaim 1c we
will examine how multiple body parts are combined in movement representations, hypothesizing that
M1 and PPC will employ a diverse set of mechanisms including linear summation, non-linear
combinations, and movement suppression expressed in different ways as a function of brain area and
the specific movement set.
Aim 2 will examine the temporal aspects of encoding in the two areas. In subaim 2a we will test the
hypothesis that the neural dynamics during sustained periods of movement are largely unchanging in
both areas. In subaim 2b we hypothesize that, during sequential movements, M1 codes only the
ongoing movement whereas PPC codes both the current and subsequent movements. Finally, in subaim
2c we will examine the coding of movement speed, with the hypothesis that there are separate
subspaces in both M1 and PPC for direction and speed of movement.

## Key facts

- **NIH application ID:** 10848218
- **Project number:** 5UG1EY032039-04
- **Recipient organization:** CALIFORNIA INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** RICHARD A ANDERSEN
- **Activity code:** UG1 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $658,011
- **Award type:** 5
- **Project period:** 2021-05-01 → 2026-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10848218

## Citation

> US National Institutes of Health, RePORTER application 10848218, Visuomotor Prosthetic for Paralysis (5UG1EY032039-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10848218. Licensed CC0.

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