Analysis of phase-locked oscillations in multi-channel single-unit spike activity with wavelet cross-spectrum

J Neurosci Methods. 2002 Mar 30;115(1):67-75. doi: 10.1016/s0165-0270(02)00002-x.

Abstract

Electrophysiological measures of neural activity frequently display oscillatory patterns at various frequencies. Furthermore, these oscillatory patterns can become dynamically synchronized across a wide region of the brain in a task-dependent manner. In this study, phase-locked oscillations in simultaneously recorded spike trains were analyzed using the wavelet cross-spectrum. Adaptation of the existent methods of calculating wavelet cross-spectrum to spike train data was straightforward. In contrast, new methods were needed for evaluating the statistical significance of the cross-spectrum. Although a permutation test based on a large number of re-sampled cross-spectra can provide a reliable estimate of statistical significance, this was quite time-consuming. As an alternative, statistical significance was determined with a normal probability density function estimated from a small number of re-sampled cross-spectra. When applied to neuron pairs recorded in the primate supplementary motor area, the re-sampling procedure produced a reliable outcome even when it was based on as few as ten re-sampled cross-spectra. These results suggest that the wavelet analysis in combination with a re-sampling procedure provides a useful tool to examine the dynamic patterns of temporal correlation in cortical spike trains.

Publication types

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

MeSH terms

  • Action Potentials / physiology*
  • Algorithms
  • Animals
  • Biological Clocks / physiology*
  • Electrophysiology / instrumentation
  • Electrophysiology / methods*
  • Macaca mulatta
  • Motor Cortex / physiology*
  • Nerve Net / physiology*
  • Neurons / physiology*
  • Signal Processing, Computer-Assisted / instrumentation*