Two conditional cross-correlation techniques are described for the analysis of two simultaneously recorded neuronal spike trains. The conditional interspike interval histogram describes the distribution of interspike intervals of a neuron conditioned by a preceding spike in another neuron. The conditional cross-internal histogram describes the distribution of cross-intervals of two neurons conditioned by a preceding spike in one of the neurons. These techniques could be used to reveal the temporal coupling in the discharge of two neurons recorded simultaneously. The techniques augment the description of the correlation obtained with conventional cross-correlation measures. When applied to the simple spike discharge of simultaneously recorded cerebellar Purkinje neurons, the methods reveal temporal interactions between neurons that are not readily apparent from conventional cross-correlograms. The patterns observed suggest a tightly coupled, temporal surround-inhibition among nearby Purkinje neurons.
Bibliographical noteFunding Information:
We wish to thank Dr. Richard Poppele for his comments, and Linda Christensen for the typing of the manuscript. Supported in part by NIH Grant NS-18338, NSF Grant BNS-8318885, the Minnesota Medical Foundation and the Graduate School of the University of Minnesota. Graphics display facilities were made available by the Biomedical Image Processing Laboratory of the University of Minnesota, NIH grant BR02422. The 3D graphics software for the Silicon Graphics IRIS Workstation is available from the authors.
- Cerebellar Purkinje neuron
- Conditional cross-interval correlation
- Conditional interspike interval correlation
- Cross-correlation technique
- Simultaneous/multiple spike train analysis