Effects of spike-triggered negative feedback on receptive-field properties

TL;DR

This paper investigates how spike-triggered negative feedback alters the receptive field properties of sensory neurons, transforming their filtering characteristics and potentially inducing resonance, with implications for understanding neural processing.

Contribution

It introduces a unified framework analyzing the impact of feedback on receptive fields, distinguishing between intrinsic and effective receptive fields, and demonstrates feedback-induced shifts from low-pass to band-pass filtering.

Findings

Feedback shifts low-pass to band-pass filtering

Strong feedback can induce spectral resonance

Receptive field properties are modulated by feedback mechanisms

Abstract

Sensory neurons are often described in terms of a receptive field, that is, a linear kernel through which stimuli are filtered before they are further processed. If information transmission is assumed to proceed in a feedforward cascade, the receptive field may be interpreted as the external stimulus' profile maximizing neuronal output. The nervous system, however, contains many feedback loops, and sensory neurons filter more currents than the ones representing the transduced external stimulus. Some of the additional currents are generated by the output activity of the neuron itself, and therefore constitute feedback signals. By means of a time-frequency analysis of the input/output transformation, here we show how feedback modifies the receptive field. The model is applicable to various types of feedback processes, from spike triggered intrinsic conductances to inhibitory synaptic inputs from nearby neurons. We distinguish between the intrinsic receptive field (filtering all input currents) and the effective receptive field (filtering only external stimuli). Whereas the intrinsic receptive field summarizes the biophysical properties of the neuron associated to subthreshold integration and spike generation, only the effective receptive field can be interpreted as the external stimulus' profile maximizing neuronal output. We demonstrate that spike-triggered feedback shifts low-pass filtering towards band-pass processing, transforming integrator neurons into resonators. For strong feedback, a sharp resonance in the spectral neuronal selectivity may appear. Our results provide a unified framework to interpret a collection of previous experimental studies where specific feedback mechanisms were shown to modify the filtering properties of neurons.