University of Wisconsin–Madison researchers Giulio Tononi and Chiara Cirelli propose quite a different theory of what happens in the sleeping brain.
New Hypothesis Explains Why We Sleep
Watch author Giulio Tononi speak about the function
of sleep at
…
Recently we have even found that prolonged or intense use of certain circuits can make local groups of neurons “fall asleep” even though the rest of the brain (and the organism itself) remains awake. Thus, if a rat stays awake longer than usual, some cortical neurons show brief periods of silence that are basically indistinguishable from the off periods observed during slow-wave sleep. Meanwhile the rat is running around, its eyes open, tending to
its business, as any awake rat would do. This phenomenon is called local sleep, and it is attracting scrutiny from other investigators. Our latest studies indicate that localized off periods also occur in the brains of sleep-deprived humans and that those periods become more frequent after intense learning. It seems that when we
have been awake for too long or have overexerted certain circuits, small chunks of the brain may take quick naps without giving notice. One wonders how many errors of judgment, silly mistakes, irritable responses
and foul moods result from local sleep in the brains of exhausted people who believe they are fully awake and in
complete control.
…from August 2013 Scientific American Magazine.
Reference:
Is Sleep Essential? Chiara Cirelli and Giulio Tononi in
PLOS Biology, Vol. 6, No. 8, pages 1605–1611; August 2008.
The Memory Function of Sleep. Susanne Diekelmann
and Jan Born in Nature Reviews Neuroscience, Vol. 11,
No. 2, pages 114–126; February 2010.
Local Sleep in Awake Rats. Vladyslav V. Vyazovskiy,
Umberto Olcese, Erin C. Hanlon, Yuval Nir, Chiara Cirelli
and Giulio Tononi in Nature, Vol. 472, pages 443–447;
April 28, 2011.
Sleep and Synaptic Homeostasis: Structural Evidence
in Drosophila. Daniel Bushey, Giulio Tononi and Chiara
Cirelli in Science, Vol. 332, pages 1576–1581; June 24, 2011.