The precision in space and time of interactions among multiple cortical sites was evaluated by examining repeating precise spatio-temporal patterns of instances in which cortical currents showed brief amplitude undulations. The amplitudes of the cortical current dipoles were estimated by applying a variant of synthetic aperture magnometry to MEG recordings of subjects tapping to metric auditory rhythms of drum beats. Brief amplitude undulations were detected in the currents by template matching at a rate of 2-3 per second. Their timing was treated as point-processes and precise spatio-temporal patterns were searched for. By randomly teetering these point processes within a time window W, we estimated the accuracy of the timing of these brief amplitude undulations and compared the results to those obtained by applying the same analysis to traces composed of random numbers. The results demonstrated that the timing accuracy of patterns was better than 3 ms. Successful classification of two different cognitive processes based on these patterns suggests that at least some of the repeating patterns are specific to a cognitive process.
- Cortico-Cortical Interactions
- Temporal Precision
- Copyright © 2015, Journal of Neurophysiology