REM sleep

Let me get real deep real quick before I go into this REM sleep.

A variety of metrics are typically used to measure REM sleep, including eye movement.

Alcohol delays the first episode of REM sleep — and reduces the subsequent amount of REM sleep you get throughout the night.

Women also entered REM sleep, characterised by high levels of brain activity and vivid dreaming, earlier than men.

The neuron density of its forebrain — the region engaged with planning, sensory processing, and emotional responses, and on which REM sleep is largely dependent — is comparable to that of primates.