Gamma-phase shifting in awake monkey visual cortex.
Gamma-band synchronization is abundant in nervous systems. Typically, the strength or precision of gamma-band synchronization is studied. However, the precise phase with which individual neurons are synchronized to the gamma-band rhythm might have interesting consequences for their impact on further processing and for spike timing-dependent plasticity. Therefore, we investigated whether the spike times of individual neurons shift systematically in the gamma cycle as a function of the neuronal activation strength. We found that stronger neuronal activation leads to spikes earlier in the gamma cycle, i.e., we observed gamma-phase shifting. Gamma-phase shifting occurred on very rapid timescales. It was particularly pronounced for periods in which gamma-band synchronization was relatively weak and for neurons that were only weakly coupled to the gamma rhythm. We suggest that gamma-phase shifting is brought about by an interplay between overall excitation and gamma-rhythmic synaptic input and has interesting consequences for neuronal coding, competition, and plasticity.
Vinck
Martin
M
Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen, 6525 EN Nijmegen, The Netherlands.
Lima
Bruss
B
Womelsdorf
Thilo
T
Oostenveld
Robert
R
Singer
Wolf
W
Neuenschwander
Sergio
S
Fries
Pascal
P
D000200:Action Potentials / Q000502:physiology*; D000465:Algorithms; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D003344:Cortical Synchronization; D004567:Electrodes, Implanted; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D008253:Macaca mulatta; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010507:Periodicity; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D009435:Synaptic Transmission / Q000502:physiology; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D014851:Wakefulness / Q000502:physiology