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r r Abstract: This work represents an attempt to bring together two important themes in neuronal dynamics. The first is the characterization of dynamic correlations in multiunit recordings of spike activity using joint-peri-stimulus time histograms (J-PSTHs) (Aertsen and Preissl, 1991: Non Linear Dynamics and Neural Networks). The second is transient phase-locking at high (gamma) frequencies, either in terms of spiking in separable spike trains (e.g., Eckhorn et al., 1988: Biol Cybern 60:121-130, Gray and Singer, 1989 Proc NatlAcad Sci USA86:1698-1702), or using continuous electrical or biomagnetic signals (e.g., Desmedt and Tomberg, 1994 Neurosci Lett 168:126-129). In this paper we suggest that transient phase-locking is necessary for frequency-specific, dynamic event-related correlations. This point is demonstrated using the gamma-frequency (36 Hz) component of neuromagnetic signals measured in the prefrontal and partial regions of a subject during self-paced movements. A J-PSTH analysis revealed dynamic changes in prefronto-parietal correlations in relation to movement onset. These frequency-specific dynamic correla- tions were associated with changes in the degree of phase-locking, of the sort reported by Desmedt and Tomberg (1994 Neurosci Lett 168:126-129).Hum. Brain Mapping 5:48-57, 1997. r 1997 Wiley-Liss, Inc. |
