Visual learning linked to deep sleep

Can lack of sleep affect our ability to learn? It appears so as researchers have found that visual learning gets cemented in the brain during the deepest part of sleep, called slow-wave sleep.

When we see something, our retinas transmit that image to the thalamus in the brain, where neurons send very basic visual information to the visual cortex to be processed, said study author Sara Aton, Assistant Professor at University of Michigan in the US.

When the brain is awake, neurons in the thalamus and cortex fire steadily to transmit visual information between them. However, in slow-wave sleep, those neurons will burst and then pause rhythmically and in synchrony, Aton said.

There is also communication in the opposite direction -- between the visual cortex and thalamus -- forming a loop of communication between the two structures, said the study published in the journal Proceedings of the National Academy of Sciences.

What is the significance of these brain waves?

Lead author Jaclyn Durkin, a doctoral student in Aton's lab, made recordings in a part of the thalamus called the lateral geniculate nucleus, which processes visual information, and the visual cortex of mice.

The researchers tracked the activity of these populations of neurons while presenting the mice with patterns of visual stimulation. They did this across many hours of subsequent sleep.

"In these mice, during visual experience, we saw immediate changes in the neurons in the thalamus, but nothing going on in the visual cortex," Aton said.

"These waves during subsequent sleep are apparently able to transfer information from the thalamus to the cortex, and that information reflects what that animal has just been looking at," Aton said.

--IANS

gb/dg