- Non-Rapid Eye Movement (NREM) Sleep also known as quiet sleep
- Rapid Eye Movement (REM) Sleep also known as active sleep or paradoxical sleep
Research suggest that the reason we forget may be because Brain falls asleep 'in stages'. This research not only explains 'amnesia' before you go to sleep, but also addresses insomnia.
The brain does not fall asleep all at once, but in stages, and this would explain why we forget the last things we do, say or read a little before falling asleep. It was discovered by researchers at the ' Niguarda and ' Sacco Hospital in Milan . The study was recently published in the journal Neuroimage. According to scientists this discovery, in which they collaborated with Departments of Psychology, University of L'Aquila and Rome, would also explain some types of sleepwalking and insomnia.
Results of the research add to increasing evidence showing that wakefulness and sleep are not mutually exclusive states, but rather part of a continuum in which different areas of the brain takes part in a progressive manner, thus allowing for the occurrence of dissociated activity patterns in different cortical and subcortical structures characterizing different conditions like insomnia as well as other physiological and pathological condition
The study showed the weak currents of some portions of the brain, particularly the hippocampus, "structure crucial for the preservation of the memories in our brain, showing that this goes into a sleep state before the cerebral cortex, which presides over the cognitive, sensory, motor, and language." In other words, the part of the brain that deals with memory falls asleep before that of language, and this explains the 'amnesia' of what we say or read before falling asleep.
To read the complete research work please read latest publication of the journal Neuroimage.