Experimentally derived model shows that adaptation acts as a powerful spatiotemporal filter of visual responses in the rat collicular neurons

Juntaute Bytautiene,Gytis Baranauskas

doi:10.1038/s41598-018-27331-2

Juntaute Bytautiene, Gytis Baranauskas

Open Access

https://doi.org/10.1038/s41598-018-27331-2

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Journal: Scientific Reports	Publication Date: Jun 12, 2018
Citations: 6	License type: open-access

Affiliation: Lithuanian University of Health Sciences

Abstract

Adaptation of visual responses enhances visual information processing mainly by preserving the full dynamic range of neuronal responses during changing light conditions and is found throughout the whole visual system. Although adaptation in the primate superior colliculus neurons has received much attention little is known about quantitative properties of such adaptation in rodents, an increasingly important model in vision research. By employing single unit recordings, we demonstrate that in the rat collicular neurons visual responses are shaped by at least two forms of adaptation. When visual stimuli were repeatedly presented in the same location, visual responses were reduced in the majority of single units. However, when the adaptor stimulus was outside a small diameter receptive field (RF), responses to stimulus onset but not offset were enhanced in the majority of units. Responses to stimulus offset were reduced less and recovered faster than responses to stimulus onset and the effect was limited to a fraction of RF area. Simulations showed that such adaptation acted as a powerful spatiotemporal filter and could explain several tuning properties of collicular neurons. These results demonstrate that in rodents the adaption of visual responses has a complex spatiotemporal structure and can profoundly shape visual information processing.

Highlights

In early days of vision science the term ‘adaptation’ was usually associated with a decreased amplitude of responses to repeated visual stimulus presentations[1,2,3]
A model based on experimental data demonstrated profound filtering effects of adaptation on visual responses of superior colliculus (SC) neurons
The first form of adaptation occurs when an adaptor and a test stimulus are co-localized inside classical receptive field (RF) resulting in diminished both ON and OFF responses, which occur following bright stimulus onset and offset correspondingly

Summary

Introduction

In early days of vision science the term ‘adaptation’ was usually associated with a decreased amplitude of responses to repeated visual stimulus presentations[1,2,3]. A simple form of adaptation manifested as a decrease in the response magnitude during repeated visual stimulus presentations has been reported in the first studies of the superior colliculus (SC) neurons[1,2,8]. Research in monkey SC revealed that even a small adaptor stimulus, covering only a fraction of the receptive field (RF) of the neuron, affected responses to any subsequent stimulus placed within RF of that neuron[9] Both the onset and the recovery from adaptation in monkey SC is very fast: light flashes lasting only 17 ms could induce a 50% reduction in the number of evoked action potentials and the responses recovered to nearly original magnitude in less than half a second[9,10,11,12]. Our quantitative data on temporal and spatial properties of adaptation allowed us to build a model, which could predict the adaptation effects on complex stimuli such as moving gratings

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