The nature of information #ow from one area of the cerebral cortex to another is poorly understood. Frequency-dependent measures of information #ow, based on multivariate autoregressive modeling of "eld potential time series, have shown promise for understanding information transactions between cortical areas (Liang et al., Neuro Report, 11 (2000) 2875}2880). In the present contribution, a time domain measure of information #ow between two areas, called the directed transinformation (DTI), is described and applied to investigate causal in#uences directly from the "eld potential time series. We show that the DTI, as a generalization of mutual information, can be measured in a rather natural way, such that the interdependence of two time series is the sum of #ow from X to >, #ow from > to X, and instantaneous #ow. We demonstrate the usefulness of this technique on both simulated data and multichannel local "eld potentials from macaque monkeys. Comparison with the frequency-dependent measure is also made. 2001 Elsevier Science B.V. All rights reserved.
['Hualou Liang', 'Mingzhou Ding', 'Steven L. Bressler']
Temporal dynamics of information flow in the cerebral cortex