Multiplicative and additive modulation of neuronal tuning with population activity affects encoded information

TL;DR

This study reveals how fluctuations in population activity modulate neuronal tuning in primate visual cortex through multiplicative and additive effects, influencing the information encoding capacity of neurons.

Contribution

It demonstrates that population activity fluctuations modulate neuronal tuning via multiplicative and additive effects, affecting information encoding in a nuanced manner.

Findings

Multiplicative modulation increases with population activity.

Additive modulation decreases with population activity.

Total information remains relatively unaffected by these modulations.

Abstract

Numerous studies have shown that neuronal responses are modulated by stimulus properties, and also by the state of the local network. However, little is known about how activity fluctuations of neuronal populations modulate the sensory tuning of cells and affect their encoded information. We found that fluctuations in ongoing and stimulus-evoked population activity in primate visual cortex modulate the tuning of neurons in a multiplicative and additive manner. While distributed on a continuum, neurons with stronger multiplicative effects tended to have less additive modulation, and vice versa. The information encoded by multiplicatively-modulated neurons increased with greater population activity, while that of additively-modulated neurons decreased. These effects offset each other, so that population activity had little effect on total information. Our results thus suggest that intrinsic activity fluctuations may act as a "traffic light" that determines which subset of neurons are most informative.