Perceptual and cognitive effects of eye blinks

We blink our eyes more often than necessary to keep our cornea adequately lubricated. Blink rates are known to fluctuate depending on the task at hand. It is known that eye blinks do modulate activity between two large scale brain networks involving the way attention is being directed. This raises the question whether there are perceptual or cognitive consequences of eye blinks that could justify the high blink rates? This research first assessed the perceptual impact of eye blinks using a behavioural paradigm. Visual performance after eye blinks has been measured using a series of rapid serial visual presentation (RSVP) tasks. We found that visual identification performance was enhanced (~15% points increased accuracy) in the first 300 ms immediately after an eye blink. A second, later period with improved performance was also observed in several of these experiments. However, the early boost only occurred for object recognition tasks. Tasks involving parietal function, or non-foveated stimuli, did not enjoy performance boosts at the same scale. In a second study, participants judged the orientations of pairs of gabor gratings that could appear at varying distances from fixation. Detection performance was boosted in one instance after eye blinks but was also better after artificial blinks. This suggests that in the case of distributed spatial attention, just the transient disruption of visual input can be sufficient to induce an attentional boost. Lastly, Magnetoencephalo-graphy (MEG) was used to investigate neural activity time-locked to eye blinks. We found attention related alpha-beta (8-30 Hz) activity stemming from the eye blink-related medial posterior parietal cortex for both voluntary eye blinks (up to ~700 ms from an eye blink) and spontaneous blinks (up to ~500 ms from an eye blink). While the role of attention related alpha-beta activity in the mPPC is unknown in this study, as attention boost was found post-eye blinks in object recognition within similar time windows, there lies the possibility of a relationship between eye blinks and the mPPC with attentional implications.Doctor of Philosoph