EoN M3 topic 2

Hunger, thirst, sex, brain waves, sleep

Long-term regulation of feeding involves…

• Fat

• Leptin

• Hypothalamus

Short-term feeding involves…

• Ghrelin

• gut distention

• Insulin

Leptin hormone involvement in eating regulation

• released by adipose tissue

• Low Leptin: Increased eating, decreased energy expenditure

• High Leptin: decreased eating, increased energy expenditure

Arcuate nucleus of Hypothalamus role in hunger

• Inhibits neurons that stimulate feeding

• stimulates neurons that inhibit eating

Pituitary role in hunger

Releases thyroid stimulating hormone

Lateral hypothalamus role in hunger

• inhibits neurons that stimulate feeding

• Modulates a subset of neurons that signal to the mesolimbic dopamine system to release dopamine

Ghrelin

• short-term regulation eating

• hormone that’s released when stomach is empty

• Opposite to leptin

What hormones are involved in parental bonding?

Vasopressin and oxytocin - released from posterior pituitary via paraventricular nucleus activity (in hypothalamus)

What hormone is released in females during romantic bonding?

Oxytocin

What hormone is released in males during romantic bonding?

vasopressin

Romantic bonding brain areas

• Ventral tegmental area

Parental bonding brain areas

• anterior cingulate cortex

Gamma rhythms

• 30-80 Hz

• concentrating, problem solving

Beta rhythms

• 13-30 Hz

• Waking state, alert, focused

• 
  

Alpha Rhythms

• 7-13Hz

• quiet, relaxed, calming state

Theta Rhythms

• 4-7Hz

• deep relaxation/light sleep, meditation

Delta Rhythms

• 0.5-4 Hz

• Deep sleep

Sleep Spindles

• Bursts of rapid rhythmic brain activity (8-14 Hz)

• May help inhibit cognitive processes or perceptions to maintain tranquil state

• Stage 2 sleep

K complex

• sharp, high amplitude negative wave followed by smaller, slower positive wave

• may be involved in memory consolidation

• Stage 2 Sleep

Sleep stage 1

• REM

• Hypnagogoic hallucinations

• Hypnic jerks

• lasts a few minutes

• Theta waves

Sleep stage 2

• REM

• Harder to awaken

• 5-15 minutes

• Sleep spindles, K complexes

Sleep stage 3

• REM

• Few eye and body movements

• 5-15 minutes

• Delta waves

Sleep stage 4

• NREM

• deep, slow wave sleep

• sleep talking

• 20-40 minutes

• Delta waves

Neural mechanisms of wakefulness

Reticular formation

Descending projections

Ascending projections

ARAS

Orexin

Released by the lateral hypothalamis, this small peptide helps to excite cells that produce modulatory neurotransmitter systems. Through these actions, it promotes wakefulness and inhibits REM sleep.

ARAS

A set of nuclei in different brain areas that regulate wakefulness and sleep-wake transitions.  Neurons in this system increase the firing rate of key modulatory neurotransmitter and orexin neurons.

Melatonin

Released by the pineal gland when darkness falls, its levels rise when we become sleepy, peak in the early morning and fall back to baseline when we wake.  It helps to initiate and maintain sleep.

Adenosine

Inhibits the modulatory neurotransmitter systems that promote wakefulness; thus high levels promote sleep.