Human intracranial high-frequency activity during memory processing: neural oscillations or stochastic volatility?

Curr Opin Neurobiol. 2015 Apr:31:104-10. doi: 10.1016/j.conb.2014.09.003. Epub 2014 Sep 30.

Abstract

Intracranial high-frequency activity (HFA), which refers to fast fluctuations in electrophysiological recordings, increases during memory processing. Two views have emerged to explain this effect: (1) HFA reflects a synchronous signal, related to underlying gamma oscillations, that plays a mechanistic role in human memory and (2) HFA reflects an asynchronous signal that is a non-specific marker of brain activation. We review recent data supporting each of these views and conclude that HFA during memory processing is more consistent with an asynchronous signal. Memory-related HFA is therefore best conceptualized as a biomarker of neural activation that can functionally map memory with high spatial and temporal precision.

Publication types

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

MeSH terms

  • Biological Clocks*
  • Brain / physiology*
  • Brain Mapping
  • Electroencephalography
  • Gamma Rhythm / physiology*
  • Humans
  • Memory / physiology*
  • Neurons / physiology
  • Stochastic Processes*