Impact of correlated neural activity on decision making performance

TL;DR

This paper investigates how correlations among neural firing rates affect decision-making accuracy, revealing that higher-order interactions can either impair or preserve performance, and that nonlinear computations may be necessary for optimal decisions.

Contribution

It demonstrates that the impact of neural correlations on decision performance depends on higher-order statistics and that nonlinear processing can be essential for optimal decision-making.

Findings

Correlations can reduce decision accuracy depending on higher-order interactions.

Standard integration may suffice in some cases, but nonlinear computations are needed in others.

Pairwise correlations do not always imply redundancy or diminished performance.

Abstract

Stimulus from the environment that guides behavior and informs decisions is encoded in the firing rates of neural populations. Each neuron in the populations, however, does not spike independently: spike events are correlated from cell to cell. To what degree does this apparent redundancy impact the accuracy with which decisions can be made, and the computations that are required to optimally decide? We explore these questions for two illustrative models of correlation among cells. Each model is statistically identical at the level of pairs cells, but differs in higher-order statistics that describe the simultaneous activity of larger cell groups. We find that the presence of correlations can diminish the performance attained by an ideal decision maker to either a small or large extent, depending on the nature of the higher-order interactions. Moreover, while this optimal performance can in some cases be obtained via the standard integration-to-bound operation, in others it requires a nonlinear computation on incoming spikes. Overall, we conclude that a given level of pairwise correlations--even when restricted to identical neural populations--may not always indicate redundancies that diminish decision making performance.