In other studies, the scientists also observed that caffeine has the same stimulating effects on human and fly sleep, and that similar genes are expressed in both species when they are awake and asleep. Tononi's team also conducted EEGs on the flies and found evidence of the same electrophysiological changes occurring during sleep and wakefulness as in humans.
"The electrical changes in humans look different that they do in flies because our brains are organized differently," Cirelli says. "But the EEGs showed electrophysiological changes signifying that the flies were asleep and awake."
In mammals the changes produce hallmark waves, or oscillations of groups of neurons, easily detected by EEG. The waves are slower during deep sleep and faster during waking times. One way of getting from the faster to the slower state is by opening ion channels, allowing potassium to flow through them.
"Our hypothesis is that if you don't have potassium channels, you won't get slow waves," Cirelli says. "The cell membrane will remain activated, preventing long periods of deep, non-REM sleep."
The researchers say that the fly research translates to humans even more than they thought it would. "Humans have the same kind of genes and potassium channels. And we know that slow waves must be generated by changes in the excitability of neuron cell membranes," Cirelli says.
"Potassium changes may have a huge affect on sleep in humans."
Sleep is a highly complex activity and probably involves many genes, some of which are more influential than others, says Cirelli. "We believe this gene is very powerful because it a
Source:University of Wisconsin-Madison