psych 220 wakefulness and sleep & internal regulation

polysomnograph

combination of EEG and eye movement records

stage 2 sleep

common characteristics= sleep spindle k-complexes (theta waves)

sleep spindle

consists of 12-14 hz waves during a burst that lasts at least half a second. sleep spindles result from oscillating interactions between cells in the thalamus and the cortex have been correlated with IQ, may be more if you have studied before sleep; may help you sleep longer

reticular formation

decrease in arousal due to damage to the reticular formation. specific part of the reticular formation =pontomesencephalon--their axons release acetylcholine and glutamate into the forebrain

biochemistry of circadian rhythm

genes (per and tim) create proteins PER and TIM. the concentration of these 2 proteins, which promote sleep and inactivity, oscillates over a day, based on feedback interactions among neurons. light--> activates a chemical that breaks down TIM protein, thereby increasing wakefulness

glycogen, so blood sugar levels do not rise too quickly. as time passes after a meal, the blood glucose levels falls, insulin levels drop, glucose enters the cells more slowly and hunger increases.

glucose stored as ____.

stage 1 sleep

irregular, jagged, low voltage waves. brain activity is less than in relaxed wakefulness but higher than other sleep stages. (theta waves)

paradoxical (REM) sleep

it is deep sleep in some ways, but light sleep in others periods of rapid eye movement low-voltage fast waves that indicate increased neuronal activity, in this regard REM sleep is light postural muscles of the body (including those that support the head) are more relaxed during REM sleep than any other stage -erections in males, vaginal moistening in females -intermittent characteristics such as facial twitches and eye movements. similar waves to stage 1, but difference in eye movements. PGO waves

endogenous circadian rhythm

last about a day circadian rhythms affect more than just sleep patterns; circadian rhythms in our eating, drinking, urination, hormone secretion, metabolism, sensitivity to drugs, and other variables.

syndromal obesity

Prader-Willi syndrom=increase ghrelin

when you fall asleep, start in stage 1 and slowly progress through 2, 3, 4 in order. after about an hour of sleep, you being to cycle back from 4 through 3, 2, and then REM. the sequence repeats, which each cycle lasting about 90 minutes.

1, 2, 3, 4 (hour of sleep), 4, 3, 2 REM early in the night stages 3 and 4 dominate. toward morning, REM occupies an increasing percentage of the time. REM depends on time of day rather than how long you have been asleep. REM dreams more likely than nREM dreams to include visual imagery and complicated plots, but not always.

4 water stores in the body

1.intracellular (67%)-->osmotic thirst 2. intravascular (7%) 3. cerebrospinal fluid (<1%) 4. interstitial fluid (26%)

brain mechanisms (areas of brain for controlling appetite) noah's arc

ARCUATE NUCLUES OF HYPOTHALAMUS 2 types of cells hunger motive, satiety motive

inhibition of brain activity due to...

GABA-mediated inhibition

k-complex

a sharp wave associated with temporary inhibition of neuronal firing

retinohypothalamic path

a small branch of the optic nerve, called the ______ ___, from the retina to the SCN, alters the SCN's settings

phenomenon where you are awake but cannot move. what is happening?

during REM sleep, cells in the pons and medulla send inhibitory messages to the spinal neurons that control the movement of large muscles. usually, when we awaken from REM, these cells are shut off, but sometimes they are not.

osmotic thirst

eating salty foods causes ___ ___.

insulin and glucagon feedback systems

eating--> blood glucose levels rise, insulin release increases->glucose enters the cell and hunger decreases--> blood sugar decreases. insulin levels decrease so glucose enters the cells more slowly--> glucagon release increase, glucose enters the blood, slowing the return of hunger-->hunger--> back to eating.

effects on steady high insulin levels on feeding

eating-->blood glucose increases, insulin level is high-->insulin helps glucose enter the cells. hunger temporarily decreases, blood glucose levels decline, but insulin levels do not--> rapid return of hunger-->eating.

people with untreated type 1 diabetes eat much but lose weight

eating-->blood glucose level increases, but insulin levels are low-->glucose does not enter cells; leaves in urine and feces instead. hunger remains high-->blood glucose levels stay high but cells are starving--> hunger-->eating.

stages 3 and 4 (delta waves)

heart rate, breathing rate, and brain activity decrease; slow, large amplitude waves become more common SLOW WAVE SLEEP slow waves indicate that neuronal activity is highly synchronized.

leptin from greek word leptos =slender think of lipton ice tea-skinny (long term satiety signal) insulin (intermediate term satiety signal) CCK (short term satiety signal) --closes sphnicter. (c)lose=cck

limited to vertebrates; in genetically normal vertebrates, the fat cells produce LEPTIN. mice with OBESE gene fail to produce LEPTIN leptin signals to brain about fat reserves, long-term indicator whether you have been overeating or undereating certain threshold of leptin reached in puberty initiates puberty. typically, thinner people enter puberty later

CCK

limits food intake in 2 ways: -constricts sphincter muscle between stomach and the duodenum -stimulates vagus nerve to send signals to hypothalamus, causing cells there to release a neurotransmitter that is a shorter version of CCK

hypovolemic thirst renin-angiotensin-aldosterone system

losing bodily fluids causes_____ ___. if your body loses a lot of fluid--body reacts with releasing hormones that CONSTRICT blood vessels. vasopressin and angiotensin II

process of digestion

mouth (saliva breaks down carbohydrates)-->esophagus-->stomach(HCl) and other acids that digest proteins-->small intestine (digests FATS, proteins, and carbs, bloodstream absorbs digested materials)--> large intestine (absorbs water and minerals and lubricates remaining food)

REM behavior disorder

move around vigorously during REM periods.

obesity

mutated gene for receptors for melanocortin variant form of FTO gene single gene mutations account for 5% of cases of obesity

night terrors/sleepwalking

occur during NREM sleep sleepwalking--more common during slow wave sleep and not accompanied by dreaming. usually does not occur during REM sleep where large muscles are relaxed.

hypothalamus contributions

one pathway releases excitatory neurotransmitter, HISTAMINE. which enhances arousal and alertness throughout the brain. orexin/hypocretin (2 different names) axons releasing orexin extend from hypothalamus to basal forebrain, ENHANCING WAKEFULNESS. not necessary for waking up, but for STAYING AWAKE

output from the arcuate nucleus then goes to...

paraventricular nucleus (PVN) of hypothalamus--> which then inhibits the LATERAL HYPOTHALAMUS (an area important for eating) LAT=LATS GOTTA GET BIG AND EAT MORE

brain areas activated by REM sleep

pons, limbic system (emotional responses)

PGO waves stand for?

pons-geniculate-occipital waves

ghrelin ghrelin--sound like grilling, so INCREASE hunger

potent chemical that increases hunger empty duodenum--> secretes ghrelin

how does the brain detect osmotic thirst? OVLT ,SFO--> PVN, supraoptic nucleus (hypothalamus)-->controls secretion of vasopressin

receptors around the 3rd ventricle, including OVLT and subfornical organ (SFO) OVLT also receives input from receptors in the digestive tract (stomach) allowing it to anticipate possible osmotic thirst. receptors in the SFO, OVLT, and stomach rely their information to several parts of the HYPOTHALAMUS --supraoptic nucleus, paraventricular nucleus (PVN). these areas control the rate at which vasopressin is produced receptors also relay information to the lateral pre optic area which control drinking

satiety mechanism

receptors for swallowing and water content of the stomach and upper part of small intestine--> ACC (anterior cingulate cortex)--> satiation OVLT still active

endogenous circannual rhythm

rhythm from within that prepares for certain seasonal changes

sleep vs. coma vs. vegetative state vs. minimally conscious state

sleep--active state that the brain goes in, decreased response to stimuli coma--little brain activity; person will have little to no response to stimuli vegetative state--alternates between periods of sleep and moderate arousal, although even when an aroused state, the person shows no awareness of surroundings or purposeful behavior. minimally conscious state--one stage higher, with occasional, brief periods of purposeful actions and a limited amount of speech comprehension. a vegetative or minimally conscious state can last for months or years. brain death--no brain activity and no response to any stimulus

zeitgeber

stimuli that reset circadian rhythms (light is the most powerful) circadian rhythm is still in effect even without light.

suprachiasmatic nucleus, hypothalamus

the main driver of rhythms for sleep and body temperature is the ___ ____, part of the ____.

the stomach and intestines, vagus

the stomach signals satiety to the brain via the ____ nerve (signals stretching of the stomach) splanchnic nerves convey information about the nutrient contents of the stomach fat in the duodenum releases a hormone called OEA which stimulates the vagus nerve, sending a message to the hypothalamus that delays the next meal. CCK=

periodic limb movement disorder

usually during NREM sleep

locus coeruleus , pons

usually inactive, especially during sleep, but it emits bursts of impulses in response to meaningful events, especially those that produce emotional arousal. "gain" releases norepinephrine; enhances the response to working neurons and decreases activity to least responsive neurons. small structure in the ____.

when dehydrated.. posterior pituitary releases VASOPRESSIN?

vasopressin--constricts blood vessels. acts as an ADH allowing kidney to reabsorb water. more concentrated urine.

output from the VMH inhibits feeding

ventromedial hypothalamus VMH

osmotic pressure

water moves from areas of low solute concentration to high levels of concentration occurs when solutes are more concentrated on one side of the semipermeable membrane than the other.

angiotensin II

when blood drops in volume, the kidneys release the enzyme RENIN--> angiotensin I--> angiotensin II

sodium specific hunger

when body's salt reserves are low, adrenal glands produce ALDOSTERONE--causing kidneys, salivary glands, and sweat glands to retain salt aldosterone=indicates low sodium angiotensin=low blood volume

POA (preoptic area)/AH (anterior hypothalamus)-->posterior hypothalamus which then stimulates portions of the midbrain that cause involuntary muscle contractions (shivering) increase in NE release to VASOCONSTRICT)

when the body is cold

POA/AH--> inhibits NE receptors to increase VASODILATION increase in cholinergic activity to increase sweating

when the body is warm

beta

which waves are associated with wakefulness?

alpha

which waves are characteristic of relaxed wakefulness?