A neural coding scheme formed by the combined function of gamma and theta oscillations

Schizophr Bull. 2008 Sep;34(5):974-80. doi: 10.1093/schbul/sbn060. Epub 2008 Jun 16.


Brain oscillations are important in controlling the timing of neuronal firing. This process has been extensively analyzed in connection with gamma frequency oscillations and more recently with respect to theta frequency oscillations. Here we review evidence that theta and gamma oscillations work together to form a neural code. This coding scheme provides a way for multiple neural ensembles to represent an ordered sequence of items. In the hippocampus, this coding scheme is utilized during the phase precession, a phenomenon that can be interpreted as the recall of sequences of items (places) from long-term memory. The same coding scheme may be used in certain cortical regions to encode multi-item short-term memory. The possibility that abnormalities in theta/gamma could underlie symptoms of schizophrenia is discussed.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Electroencephalography*
  • Hippocampus / physiopathology*
  • Humans
  • Memory Disorders / epidemiology
  • Memory Disorders / physiopathology
  • Memory, Short-Term
  • Mental Recall
  • Schizophrenia / epidemiology
  • Schizophrenia / physiopathology*