Category: memory

>Sleep is good for you


Sunday is one of my favourite days as I tend to have time to do some reading. I like to read everything, but today i particularly enjoyed something recently published on sleep using an interesting animal model.

The benefits of sleep seem obvious. However, scientists have long debated precisely how it improves brain performance at the cellular level. One theory argues that sleep reduces the unimportant connections between neurons, preventing brain overload. Another theory maintains that sleep consolidates memories from the previous day.

I have previously discussed in this blog the importance of sleep for athletes with particular reference to the possibility of videogames altering the normal sleep-wake cycle.

Recent work published on Neuron shows how the circadian clock and sleep affect the scope of neuron-to-neuron connections in a particular region of the brain. The authors also identified a gene that appears to regulate the number of these connections.

The study was conduced studying the larvae of a common see-through aquarium pet, the zebrafish. Like humans, zebrafish are active during the day and sleep at night.

The researchers, led by Lior Appelbaum and Philippe Mourrain of Stanford University, tagged the larvae neurons with a dye (Synaptophysin,  pre-synaptic marker) so that active neuron connections, or synapses, appeared green, whereas inactive ones appeared black.

High-quality image (930K) - Opens new window

After following the fluctuations of these synapses over the course of a day, the team found that the zebrafish did indeed have lower overall synapse activity during sleep.

The scientist are pretty much of the impression that sleep is an active process that reduces the activity in the brain. This reduction in brain activity allows the brain to recover from past experiences.

Without the synapse reduction that happens during sleep the brain would not have the ability to continually take in and store new information. So the importance of sleep i an athletic population is not relevant only for physical recovery, but possibly to facilitate learning and memory all activities incredibly important in sports where tactical aspects are crucial.

More studies are needed but this particular study provides the first insights on NPTX2, a protein implicated in AMPA receptor clustering which modulates circadian synaptic changes. Overexpression of NPTX2b in hypocretin/orexin (HCRT) neurons induces melatonin resistance, so for sure there is a need for more studies in this field to understand the links between sleep and brain function.