The Dynamical Regime of Sensory Cortex: Stable Dynamics around a Single Stimulus-Tuned Attractor Account for Patterns of Noise Variability

Neuron. 2018 May 16;98(4):846-860.e5. doi: 10.1016/j.neuron.2018.04.017.

Abstract

Correlated variability in cortical activity is ubiquitously quenched following stimulus onset, in a stimulus-dependent manner. These modulations have been attributed to circuit dynamics involving either multiple stable states ("attractors") or chaotic activity. Here we show that a qualitatively different dynamical regime, involving fluctuations about a single, stimulus-driven attractor in a loosely balanced excitatory-inhibitory network (the stochastic "stabilized supralinear network"), best explains these modulations. Given the supralinear input/output functions of cortical neurons, increased stimulus drive strengthens effective network connectivity. This shifts the balance from interactions that amplify variability to suppressive inhibitory feedback, quenching correlated variability around more strongly driven steady states. Comparing to previously published and original data analyses, we show that this mechanism, unlike previous proposals, uniquely accounts for the spatial patterns and fast temporal dynamics of variability suppression. Specifying the cortical operating regime is key to understanding the computations underlying perception.

Keywords: MT; V1; circuit dynamics; cortical variability; noise correlations; theoretical neuroscience; variability quenching.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Macaca
  • Neural Inhibition / physiology
  • Neural Networks, Computer
  • Neurons / physiology*
  • Nonlinear Dynamics
  • Occipital Lobe / cytology
  • Occipital Lobe / physiology
  • Visual Cortex / cytology
  • Visual Cortex / physiology*