Learning temporal context shapes the prestimulus alpha oscillations and improves the visual discrimination performance

Time is an inseparable component of every physical event that we perceive, yet it is not clear how the brain processes time or how the neuronal representation of time affects our perception of events. Here, we asked subjects to perform a visual discrimination task, while we changed the temporal context in which the stimuli were presented. We collected electroencephalography (EEG) signals in two temporal contexts. Predictable blocks: stimuli were presented after a constant delay relative to a visual cue, and unpredictable blocks: stimuli were presented after variable delays relative to the visual cue. Four sub-second delays of 83, 150, 400 and 800 ms were used in the predictable and unpredictable blocks. We observed that predictability modulated the power of prestimulus alpha oscillations in the parieto-occipital sites and this modulation only occurred in the longest delay period, 800 ms, in which the predictability also improved the behavioral performance of the subjects. Moreover, learning the temporal context shaped the prestimulus alpha power: modulation of prestimulus alpha power grew during the predictable block and correlated with performance enhancement. These results suggest that the brain is able to learn the sub-second temporal context of stimuli and use this to enhance the sensory processing. Furthermore, the neural correlate of this temporal prediction is reflected in the alpha oscillations.

from Physiology via xlomafota13 on Inoreader http://ift.tt/2quSfXT
via IFTTT