From perception to action: phase-locked gamma oscillations correlate with reaction times in a speeded response task.
BACKGROUND
Phase-locked gamma oscillations have so far mainly been described in relation to perceptual processes such as sensation, attention or memory matching. Due to its very short latency ( approximately 90 ms) such oscillations are a plausible candidate for very rapid integration of sensory and motor processes.


RESULTS
We measured EEG in 13 healthy participants in a speeded reaction task. Participants had to press a button as fast as possible whenever a visual stimulus was presented. The stimulus was always identical and did not have to be discriminated from other possible stimuli. In trials in which the participants showed a fast response, a slow negative potential over central electrodes starting approximately 800 ms before the response and highly phase-locked gamma oscillations over central and posterior electrodes between 90 and 140 ms after the stimulus were observed. In trials in which the participants showed a slow response, no slow negative potential was observed and phase-locked gamma oscillations were significantly reduced. Furthermore, for slow response trials the phase-locked gamma oscillations were significantly delayed with respect to fast response trials.


CONCLUSIONS
These results indicate the relevance of phase-locked gamma oscillations for very fast (not necessarily detailed) integration processes.
Fründ
Ingo
I
Institute of Psychology, Department of Biological Psychology, Otto-von-Guericke University, Magdeburg, Germany. ingo.fruend@nat.uni-magdeburg.de <ingo.fruend@nat.uni-magdeburg.de>
Busch
Niko A
NA
Schadow
Jeanette
J
Körner
Ursula
U
Herrmann
Christoph S
CS
D000328:Adult; D001683:Biological Clocks / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology; D006801:Humans; D010465:Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*