Sleep disorders in its deepest phase, the so-called. slow wave sleep negatively affects memory and reduces hippocampus activation, brain region responsible for remembering – according to scientists from the Netherlands in the magazine “Nature Neuroscience”. Slow-wave sleep is also called sleep without rapid eye movements (NREM), it is the period of the deepest sleep and synchronization of the biolelectric activity of the brain. You know, that sleep after studying improves the results on memory tests – helps to consolidate the acquired information. Ysbrand Van Der Werf together with colleagues from the Netherlands Institute of Neuroscience in Amsterdam showed, that the type of sleep is also important for the process of remembering, what's its quantity. Scientists conducted an experiment, in which they studied the electrical activity of the brains of sleeping participants using the EEG method (electroencephalogram). When the subjects reached the slow-wave sleep phase (visible in the EEG) a type of alarm clock emitting short beeps was activated automatically. Although the sound did not wake the participants, it did, that they were going into a different, shallower form of sleep. As a result, the length of sleep of the respondents did not change, only its depth was modified. Turned out, that upon awakening, these participants had less memory of the scenes during the test, than people who have not had a sleep disturbance. The final stage of the experiment was to analyze the participants' brain activity, whose sleep was disturbed, while watching scenes to remember (by means of functional magnetic resonance – fMRI).
The results showed, that they have reduced activity in the hippocampus – the region of the brain responsible for preserving and recalling memories. The authors conclude that, that their discovery proves, that too little sleep can disturb, in particular, hippocampal-dependent memory.
