SLEEP

BIOLOGICAL CLOCKS Circadian rhythms – daily

cycles of ~ 24 hours Pineal gland regulation –

releases melatonin Suprachiasmatic Nucleus

(SCN) acts as a biological clock Found in the hypothalamus Just above the optic chiasm Receives info from the retina

Retinohypothalamic pathway

GABA released from the hypothalamus shuts down arousal systems

RETICULAR ACTIVATING SYSTEM

RAS is responsible for sleep/wake behavior and arousal

Sensory systems RAS Cortex

Cortex can stimulate RAS suggesting wakefulness can be consciously maintained

ANATOMY OF DREAMING During REM Sleep

ACTIVEReticular formationThalamusHypothalamusAmygdala & HippocampusVisual Cortex

INACTIVEParietal CortexPrefrontal Cortex

SLEEP IN ANIMALS

Sleep is risky! Why is sleep

important? Adaptation

Energy conservation Predator vs. prey

WHAT DOES SLEEP DO FOR US? Restoration and repair, maintaining

homeostasisSleep deprivation studies show poor

cognition and physiological consequences MEMORY!!!

Activation during REM sleep