# Optical measurement of causal functional connectivity in posterior parietal cortex

> **NIH NIH F32** · HARVARD MEDICAL SCHOOL · 2021 · $70,310

## Abstract

Project Summary
The mouse posterior parietal cortex (PPC) has emerged as an essential region for decision-making during
memory-guided decision-making tasks. Neurons in the PPC typically respond selectively at a single point during
a unique behavioral trial type; activity at the population level can be thought of as a choice-specific trajectory
through state space. Many neurons respond selectively for behavioral choice; these responses resemble those
observed in models incorporating winner-take-all dynamics, but the extent to which PPC functions as a winner-
take-all network remains unknown. Key features of winner-take-all neural networks include choice-specific
excitatory connectivity and mutual inhibition between pools of neurons with different choice preferences.
To test models of neural circuit architecture in decision-making areas, we propose to develop a high-speed, high-
throughput two-photon photostimulation approach to optically measure causal functional connectivity between
neurons. We will first develop and characterize this photostimulation approach with in vivo cell-attached
recordings. Next, we will apply this photostimulation approach to measure causal functional connectivity between
excitatory neurons in PPC to test the degree of functional specificity in excitatory networks. These experiments
will relate separately measured activity-behavior relationships to causal functional connectivity measurements
between excitatory neurons and test whether neurons exhibiting similar choice preferences preferentially excite
one another. Finally, we will measure the effect of stimulating GABAergic neurons in PPC while the mouse
performs a memory-guided two-alternative forced choice task to measure causal functional connectivity between
GABAergic neurons and excitatory neurons. If PPC exhibits winner-take-all dynamics, we would expect to find
that GABAergic neurons preferentially inhibit excitatory neurons with opposite choice preferences. As a whole,
we predict that this technique will generate powerful data that provide new insight into the microcircuitry of
decision-making in PPC.

## Key facts

- **NIH application ID:** 10064584
- **Project number:** 5F32MH118698-03
- **Recipient organization:** HARVARD MEDICAL SCHOOL
- **Principal Investigator:** Daniel E Wilson
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $70,310
- **Award type:** 5
- **Project period:** 2018-12-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10064584

## Citation

> US National Institutes of Health, RePORTER application 10064584, Optical measurement of causal functional connectivity in posterior parietal cortex (5F32MH118698-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10064584. Licensed CC0.

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