title: Stochastic emergence of repeating cortical motifs in spontaneous membrane potential fluctuations in vivo.
abstract: It was recently discovered that subthreshold membrane potential fluctuations of cortical neurons can precisely repeat during spontaneous activity, seconds to minutes apart, both in brain slices and in anesthetized animals. These repeats, also called cortical motifs, were suggested to reflect a replay of sequential neuronal firing patterns. We searched for motifs in spontaneous activity, recorded from the rat barrel cortex and from the cat striate cortex of anesthetized animals, and found numerous repeating patterns of high similarity and repetition rates. To test their significance, various statistics were compared between physiological data and three different types of stochastic surrogate data that preserve dynamical characteristics of the recorded data. We found no evidence for the existence of deterministically generated cortical motifs. Rather, the stochastic properties of cortical motifs suggest that they appear by chance, as a result of the constraints imposed by the coarse dynamics of subthreshold ongoing activity.
authors.affiliation: Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Alik
authors.initials: A
authors.lastname: Mokeichev
authors.forename: Michael
authors.initials: M
authors.lastname: Okun
authors.forename: Omri
authors.initials: O
authors.lastname: Barak
authors.forename: Yonatan
authors.initials: Y
authors.lastname: Katz
authors.forename: Ohad
authors.initials: O
authors.lastname: Ben-Shahar
authors.forename: Ilan
authors.initials: I
authors.lastname: Lampl
mesh_terms: D000465:Algorithms; D000818:Animals; D002415:Cats; D002452:Cell Count; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D013269:Stochastic Processes; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology