AP PSYCHOLOGY

Detailed explanation-1: -Motor responses were evoked during sleep using stimuli identical to those used in wakefulness. Response amplitudes were depressed during slow wave sleep (SWS) and enhanced or the same during REM sleep. These findings suggest that the susceptibility of the human motor cortex to stimulation is enhanced during REM sleep.

Detailed explanation-2: -The brain stem (especially the pons and medulla) also plays a special role in REM sleep; it sends signals to relax muscles essential for body posture and limb movements, so that we don’t act out our dreams.

Detailed explanation-3: -Rapid eye movement (REM) sleep is generated and maintained by the interaction of a variety of neurotransmitter systems in the brainstem, forebrain, and hypothalamus. Within these circuits lies a core region that is active during REM sleep, known as the subcoeruleus nucleus (SubC) or sublaterodorsal nucleus.

Detailed explanation-4: -Altogether, inhibitory REM-on neurons have been discovered in multiple brain areas including medulla, pons, midbrain, and hypothalamus. A common mechanism by which these different areas promote REM sleep is inhibition of REM-off neurons in the vlPAG resulting in disinhibition of the SLD (Figure 2).