Context‐dependent coding and gain control in the auditory system of crickets

Abstract

Sensory systems process stimuli that greatly vary in intensity and complexity. To maintain efficient information transmission, neural systems need to adjust their properties to these different sensory contexts, yielding adaptive or stimulus-dependent codes. Here, we demonstrated adaptive spectrotemporal tuning in a small neural network, i.e. the peripheral auditory system of the cricket. We found that tuning of cricket auditory neurons was sharper for complex multi-band than for simple single-band stimuli. Information theoretical considerations revealed that this sharpening improved information transmission by separating the neural representations of individual stimulus components. A network model inspired by the structure of the cricket auditory system suggested two putative mechanisms underlying this adaptive tuning: a saturating peripheral nonlinearity could change the spectral tuning, whereas broad feed-forward inhibition was able to reproduce the observed adaptive sharpening of temporal tuning. Our study revealed a surprisingly dynamic code usually found in more complex nervous systems and suggested that stimulus-dependent codes could be implemented using common neural computations.

The use of computational modeling to link sensory processing with behavior in Drosophila

“…Separating input-output transformations thus helps to discriminate changes in overall response gain from changes in stimulus selectivity. For example, motivation, context, or attention can change the overall gain of responses -and therefore affect the nonlinearity -without changing the feature selectivity of the response represented by the filter (Baccus and Meister 2002;Rabinowitz et al 2011;Clemens et al 2015b). …”