Spontaneous Fluctuations and Non-linear Ignitions: Two Dynamic Faces of Cortical Recurrent Loops

Neuron. 2015 Oct 7;88(1):194-206. doi: 10.1016/j.neuron.2015.09.018.


Recent human neurophysiological recordings have uncovered two fundamental modes of cerebral cortex activity with distinct dynamics: an active mode characterized by a rapid and sustained activity ("ignition") and a spontaneous (resting-state) mode, manifesting ultra-slow fluctuations of low amplitude. We propose that both dynamics reflect two faces of the same recurrent loop mechanism: an integration device that accumulates ongoing stochastic activity and, either spontaneously or in a task-driven manner, crosses a dynamic threshold and ignites, leading to content-specific awareness. The hypothesis can explain a rich set of behavioral and neuronal phenomena, such as perceptual threshold, the high non-linearity of visual responses, the subliminal nature of spontaneous activity fluctuations, and the slow activity buildup anticipating spontaneous behavior (e.g., readiness potential). Further elaborations of this unified scheme, such as a cascade of integrators with different ignition thresholds or multi-stable states, can account for additional complexities in the repertoire of human cortical dynamics.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Awareness / physiology*
  • Cerebral Cortex / physiology*
  • Electroencephalography
  • Humans
  • Neurons / physiology*
  • Nonlinear Dynamics
  • Sensory Thresholds / physiology*