Adaptation without Plasticity

Maria Del Mar Quiroga,Adam P Morris,Bart Krekelberg

doi:10.1016/j.celrep.2016.08.089

Maria Del Mar Quiroga, Adam P Morris + Show 1 more

Open Access

https://doi.org/10.1016/j.celrep.2016.08.089

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Abstract

Sensory adaptation is a phenomenon in which neurons are affected not only by their immediate input but also by the sequence of preceding inputs. In visual cortex, for example, neurons shift their preferred orientation after exposure to an oriented stimulus. This adaptation is traditionally attributed to plasticity. We show that a recurrent network generates tuning curve shifts observed in cat and macaque visual cortex, even when all synaptic weights and intrinsic properties in the model are fixed. This demonstrates that, in a recurrent network, adaptation on timescales of hundreds of milliseconds does not require plasticity. Given the ubiquity of recurrent connections, this phenomenon likely contributes to responses observed across cortex and shows that plasticity cannot be inferred solely from changes in tuning on these timescales. More broadly, our findings show that recurrent connections can endow a network with a powerful mechanism to store and integrate recent contextual information.

Highlights

Neurons in primary visual cortex (V1) are strongly tuned to the orientation of visual stimuli within their receptive fields (Hubel and Wiesel, 1962)
We studied the dynamics of a recurrent network model of orientation tuning in primary visual cortex (Carandini and Ringach, 1997; Somers et al, 1995; Teich and Qian, 2003)
We found that the Inspired by the substantial difference in magnitude and dynamics between the C- and M-model, we performed a wider parameter exploration and found that the model architecture could generate very large ($10) and long-lasting ($1 s) tuning curve shifts, while still maintaining basic tuning properties for isolated stimuli consistent with recordings in V1

Summary

Introduction

Neurons in primary visual cortex (V1) are strongly tuned to the orientation of visual stimuli within their receptive fields (Hubel and Wiesel, 1962). Several studies have shown that the orientation preference of single neurons is altered by exposure to oriented stimuli (Clifford et al, 2001; Dragoi et al, 2000, 2002; Felsen et al, 2002; Mu€ller et al, 1999; Patterson et al, 2013, 2014; Wissig and Kohn, 2012) These alterations in neural responses have been linked to perceptual phenomena such as the tilt after-effect (TAE), where adaptation produces a ‘‘repulsive’’ shift in orientation perception (i.e., perception of orientation is biased away from that of the adaptor stimulus) (Gibson and Radner, 1937). Analogous adaptation effects are found in all sensory brain areas and are thought to provide a functional benefit by enhancing discriminability of stimuli that are prevalent in the environment (Krekelberg et al, 2006b; Kristjansson, 2011; Mu€ller et al, 1999; Schlack et al, 2007) or by increasing detectability of rare stimuli (Clifford et al, 2001; Dragoi et al, 2002)

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