Blinking Suppresses the Neural Response to Unchanging Retinal Stimulation

Abstract

Blinks profoundly interrupt visual input but are rarely noticed, perhaps because of blink suppression, a visual-sensitivity loss that begins immediately prior to blink onset. Blink suppression is thought to result from an extra-retinal signal that is associated with the blink motor command and may act to attenuate the sensory consequences of the motor action. However, the neural mechanisms underlying this phenomenon remain unclear. They are challenging to study because any brain-activity changes resulting from an extra-retinal signal associated with the blink motor command are potentially masked by profound neural-activity changes caused by the retinal-illumination reduction that results from occlusion of the pupil by the eyelid. Here, we distinguished direct top-down effects of blink-associated motor signals on cortical activity from purely mechanical or optical effects of blinking on visual input by combining pupil-independent retinal stimulation with functional MRI (fMRI) in humans. Even though retinal illumination was kept constant during blinks, we found that blinking nevertheless suppressed activity in visual cortex and in areas of parietal and prefrontal cortex previously associated with awareness of environmental change. Our findings demonstrate active top-down modulation of visual processing during blinking, suggesting a possible mechanism by which blinks go unnoticed.

Signal quality of simultaneously recorded invasive and non-invasive EEG

“…3), i.e. the region where based on previous functional imaging results (Bodis-Wollner et al, 1999;Bristow et al, 2005) blink-related brain response might have been expected (see Discussion).…”

“…We, therefore, conclude that these fronto-anterior ECoG potentials reflect ocular blink artifacts that extend to the intracranial space through mechanisms of electrical volume conduction. This conclusion is supported by the fact that previous neuroimaging studies on the neuronal basis of blinking lend little support for the assumption that the anterior prefrontal region is a major site of blink-related brain activation (Bodis-Wollner et al, 1999;Bristow et al, 2005;Kato and Miyauchi, 2003;Tsubota et al, 1999;van Eimeren et al, 2001 For each electrode position, the Z-score of the blink related artifact at the time point of the artifact peak (see Material and methods for further details) is given. Fig.…”

“…Blink related brain responses in the frontal lobe -the anatomical region of interest of our study -have been addressed in a series of previous neuroimaging studies ( Bodis-Wollner et al, 1999;Bristow et al, 2005;Kato and Miyauchi, 2003;Tsubota et al, 1999;van Eimeren et al, 2001). The regions that were most consistently reported to show blink related responses were the frontal eye field (FEF) (BodisWollner et al, 1999;Bristow et al, 2005) and the supplementary eye field (SEF) (Bodis-Wollner et al, 1999;Bristow et al, 2005;Kato and Miyauchi, 2003). In contrast, Tsubota et al (1999) found blinkrelated responses in the orbitofrontal cortex and proposed that this region might be the primary site of blink control, especially of the blink rate.…”

Catching the mind in flight: Using behavioral indices to detect mindless reading in real time

“…In addition, a recent study by Smilek, Carriere, and Cheyne (2010) showed that mindless reading is associated with increased blinking. This result could help explain the deficit in encoding the lexical features of words, since frequent blinking is associated with deactivation of cortical areas that process the external visual world (Bristow, Haynes, Sylvester, Frith, & Rees, 2005). Consistent with these findings are results indicating that reading comprehension can be compromised when critical regions of the text are poorly encoded (Christianson, Williams, Zacks, & Ferreira, 2006;Sanford & Graesser, 2006;Stine-Morrow, Noh, & Shake, 2010).…”

Human brain activity time-locked to rapid eye movements during REM sleep

“…In most studies that reported activation of the visual cortex accompanying saccades in total darkness, subjects were required to keep their eyes open. On the contrary, our subjects were required to keep their eyes closed in order to avoid misinformed activation by blink (Kato and Miyauchi 2003;Bristow et al 2005) and to equalize the physical condition of the eyes between the saccade experiment and REM sleep experiment. Therefore, saccades with closed eyes might underlie the lack of activation in the visual cortex in the present experiment.…”