Neuroscience
Twenty minutes of bright white light delays sleepiness, and sends a stimulating wave through the brain, enhancing neural activity even during tasks that have nothing to do with vision.
Gilles Vandewalle and colleagues used an optic fibre to shine bright white light into either the left or right eye of 19 participants, and then left them to sit in the dark. For most of the participants, the light exposure delayed the onset of self-reported sleepiness. Brain imaging showed this sustained alertness was related to altered activity in the thalamus, a structure buried deep in the brain.
Brain imaging also showed the light enhanced the activity of brain regions engaged when the participants subsequently completed an auditory oddball task in the dark (i.e. listen out for odd tones that don’t match all the others). These regions included areas at the front and back of the brain known to be involved in paying attention.
The effects of the light exposure were short-lived, lasting less than 10 minutes beyond the end of the light stimulation. However, the researchers believe their observations are evidence that the brain has a “non-image” forming (NIF) system that responds to light but which is quite separate from vision. They argue the NIF system response outlasts light exposure, in contrast to the classic visual system which only responds during light stimulation. “These findings suggest that light can modulate activity of subcortical structures involved in alertness, thereby dynamically promoting cortical activity in networks involved in ongoing non-visual cognitive processes”, the researchers concluded.
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Vandewalle, G., Balteau, E., Philips, C., Degueldre, C., Moreau, V., Sterpenich, V., Albouy, G., Darsaud, A., Desseilles, M., Dang-Vu, T.T., Peigneux, P., Luxen, A., Dijk, D-J. & Maquet, P. (2006). Daytime light exposure dynamically enhances brain responses. Current Biology, 16, 1616-1621.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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Neuroscience
The brain invigorated by light
Twenty minutes of bright white light delays sleepiness, and sends a stimulating wave through the brain, enhancing neural activity even during tasks that have nothing to do with vision.Gilles Vandewalle and colleagues used an optic fibre to shine bright white light into either the left or right eye of 19 participants, and then left them to sit in the dark. For most of the participants, the light exposure delayed the onset of self-reported sleepiness. Brain imaging showed this sustained alertness was related to altered activity in the thalamus, a structure buried deep in the brain.
Brain imaging also showed the light enhanced the activity of brain regions engaged when the participants subsequently completed an auditory oddball task in the dark (i.e. listen out for odd tones that don’t match all the others). These regions included areas at the front and back of the brain known to be involved in paying attention.
The effects of the light exposure were short-lived, lasting less than 10 minutes beyond the end of the light stimulation. However, the researchers believe their observations are evidence that the brain has a “non-image” forming (NIF) system that responds to light but which is quite separate from vision. They argue the NIF system response outlasts light exposure, in contrast to the classic visual system which only responds during light stimulation. “These findings suggest that light can modulate activity of subcortical structures involved in alertness, thereby dynamically promoting cortical activity in networks involved in ongoing non-visual cognitive processes”, the researchers concluded.
___________________________________
Vandewalle, G., Balteau, E., Philips, C., Degueldre, C., Moreau, V., Sterpenich, V., Albouy, G., Darsaud, A., Desseilles, M., Dang-Vu, T.T., Peigneux, P., Luxen, A., Dijk, D-J. & Maquet, P. (2006). Daytime light exposure dynamically enhances brain responses. Current Biology, 16, 1616-1621.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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Most brain imaging experiments tend to follow a similar pattern - instruct the participant to perform some task, or show them a picture, or play them a sound, and then see which areas of their brain light up. This approach has propagated a misconception...
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In blind people, the part of the brain usually used for vision can be commandeered by other senses, resulting in improved hearing and touch. It’s an amazing testament to the brain’s ability to adapt. But now, Jorg Lewald reports that prolonged blindness...
- How Doing Affects Seeing
Training to perform certain movements, even blindfolded, affects our subsequent ability to perceive those same movements when performed by others. That’s according to Antonino Casile and Martin Giese at the University Clinic Tubingen, who say their...
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