title: Robust gamma coherence between macaque V1 and V2 by dynamic frequency matching.
abstract: Current theories propose that coherence of oscillatory brain activity in the gamma band (30-80 Hz) constitutes an avenue for communication among remote neural populations. However, reports documenting stimulus dependency and time variability of gamma frequency suggest that distant neuronal populations may, at any one time, operate at different frequencies precluding synchronization. To test this idea, we recorded from macaque V1 and V2 simultaneously while presenting gratings of varying contrast. Although gamma frequency increased with stimulus contrast in V1 and V2 (by ∼25 Hz), V1-V2 gamma coherence was maintained for all contrasts. Moreover, while gamma frequency fluctuated by ∼15 Hz during constant contrast stimulation, this fluctuation was highly correlated between V1 and V2. The strongest coherence connections showed a layer-specific pattern, matching feedforward anatomical connectivity. Hence, gamma coherence among remote populations can occur despite large stimulus-induced and time-dependent changes in gamma frequency, allowing communication through coherence to operate without a stimulus independent, fixed-frequency gamma channel.
authors.affiliation: Donders Institute for Brain, Behavior and Cognition, Radboud University, 6500 HC Nijmegen, the Netherlands. mark.roberts@maastrichtuniversity.nl
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Roberts
authors.forename: Eric
authors.initials: E
authors.lastname: Lowet
authors.forename: Nicolas M
authors.initials: NM
authors.lastname: Brunet
authors.forename: Marije
authors.initials: M
authors.lastname: Ter Wal
authors.forename: Paul
authors.initials: P
authors.lastname: Tiesinga
authors.forename: Pascal
authors.initials: P
authors.lastname: Fries
authors.forename: Peter
authors.initials: P
authors.lastname: De Weerd
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D015350:Contrast Sensitivity / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*