Sleep Stages, Brain Waves, and Circadian Regulation: NREM, REM, and Hypothalamic Pathways

NREM 1

Muscles still somewhat active

Brain waves get lower and lower frequencies

Alpha waves(8-13) to theta waves(4-8)

NREM 2

Theta waves(4-8hz)

Research suggest that the k complex and the sleep spindles may happen because of memory processing and also minimizing perception of distracting sounds

NREM 3(SWS)

Delta waves(0.5-4hz)

Called deep sleep

Heart rate, respiration and blood pressure drop to the lowest point

Slow wave sleep

Large amplitudes , low frequency

Suprachiasmatic neurons

The suprachiasmatic neuron is in the hypothalamus

Excites the pineal gland to release melatonin

Uses visual information about light to either inhibit or excite the pineal gland

Retinohypothalamic tract

An alternate pathway that turns light into signals that go to the Suprachiasmatic neurons

More activity(more light) causes the SCN to inhibit the pineal gland more

VLPO(ventrolateral preoptic neuron)

Produces GABA which inhibits arousal(mainly in NREM)