Symmetric temporal patterns in cortical spike trains during performance of a short-term memory task.
The trion model is a highly structured representation of cortical organization, which predicts families of symmetric spatial-temporal firing patterns inherent in cortical activity. The symmetries of these inherent firing patterns are used by the brain in short-term memory to perform higher level computations. In the present study, symmetric temporal patterns were searched for in spike trains recorded from cells in parietal cortex of a monkey performing a short-term memory task. A new method of analysis was used to map neuronal firing into sequences of integers representing relative levels of firing rate about the mean (i.e. -1, 0 and 1). The results of this analysis show families of patterns related by symmetry operations. These operations are: i. the interchanging of all the +1's and -1's in a given pattern sequence (C symmetry), ii. the inverting of the temporal sequence of the mapping (T symmetry), and iii. the combination of the two previous operations (CT symmetry). Patterns of a given family are found across cells, especially in the memory periods of the task; in most cases they reoccur within a given spike train. The pattern families predicted by the model and reported here should be further investigated in multiple microelectrode and EEG recordings.
Bodner
M
M
Department of Psychiatry and Brain Research Institute, School of Medicine, University of California, Los Angeles, USA.
Zhou
Y D
YD
Shaw
G L
GL
Fuster
J M
JM
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004569:Electroencephalography; D000882:Haplorhini; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology*; D013997:Time Factors