PT - JOURNAL ARTICLE AU - Daeyeol Lee TI - Coherent Oscillations in Neuronal Activity of the Supplementary Motor Area during a Visuomotor Task AID - 10.1523/JNEUROSCI.23-17-06798.2003 DP - 2003 Jul 30 TA - The Journal of Neuroscience PG - 6798--6809 VI - 23 IP - 17 4099 - http://www.jneurosci.org/content/23/17/6798.short 4100 - http://www.jneurosci.org/content/23/17/6798.full SO - J. Neurosci.2003 Jul 30; 23 AB - Neural activity recorded in behaving animals is nonstationary, making it difficult to determine factors influencing its temporal patterns. In the present study, rhesus monkeys were trained to produce a series of visually guided hand movements according to the changes in target locations, and multichannel single-neuron activity was recorded from the caudal supplementary motor area. Coherent oscillations in neural activity were analyzed using the wavelet cross-spectrum, and its statistical significance was evaluated using various methods based on surrogate spike trains and trial shuffling. A population-averaged wavelet cross-spectrum displayed a strong tendency for oscillatory activity in the γ frequency range (30∼50 Hz) to synchronize immediately before and after the onset of movement target. The duration of synchronized oscillations in the γ frequency range increased when the onset of the next target was delayed. In addition, analysis of individual neuron pairs revealed that many neuron pairs also displayed coherent oscillations in the β frequency range (15-30 Hz). Coherent β frequency oscillations were less likely to be synchronized than γ frequency oscillations, consistent with the fact that coherent β frequency oscillations were not clearly seen in the population-averaged cross-spectrum. For a given neuron pair, the time course and phase of coherent oscillations were often similar across different movements. These results are consistent with the proposal that synchronized oscillations in the γ frequency range might be related to the anticipation of behaviorally relevant events and the contextual control of cortical information flow.