RT Journal Article
SR Electronic
T1 This Is the Rhythm of Your Eyes: The Phase of Ongoing Electroencephalogram Oscillations Modulates Saccadic Reaction Time
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4698
OP 4708
DO 10.1523/JNEUROSCI.4795-10.2011
VO 31
IS 12
A1 Jan Drewes
A1 Rufin VanRullen
YR 2011
UL http://www.jneurosci.org/content/31/12/4698.abstract
AB Motor reaction times in humans are highly variable from one trial to the next, even for simple and automatic tasks, such as shifting your gaze to a suddenly appearing target. Although classic models of reaction time generation consider this variability to reflect intrinsic noise, some portion of it could also be attributed to ongoing neuronal processes. For example, variations of alpha rhythm frequency (8–12 Hz) across individuals, or alpha amplitude across trials, have been related previously to manual reaction time variability. Here we investigate the trial-by-trial influence of oscillatory phase, a dynamic marker of ongoing activity, on saccadic reaction time in three paradigms of increasing cognitive demand (simple reaction time, choice reaction time, and visual discrimination tasks). The phase of ongoing prestimulus activity in the high alpha/low beta range (11–17 Hz) at frontocentral locations was strongly associated with saccadic response latencies. This relation, present in all three paradigms, peaked for phases recorded ∼50 ms before fixation point offset and 250 ms before target onset. Reaction times in the most demanding discrimination task fell into two distinct modes reflecting a fast but inaccurate strategy or a slow and efficient one. The phase effect was markedly stronger in the group of subjects using the faster strategy. We conclude that periodic fluctuations of electrical activity attributable to neuronal oscillations can modulate the efficiency of the oculomotor system on a rapid timescale; however, this relation may be obscured when cognitive load also adds a significant contribution to response time variability.