hefnawy - sleep and limbic system

Question 1

structures involved in sleep

Answer 1

suprachiasmatic nucleus (circadian rhythms) and pineal gland (melatonin)

Question 2

reticular activation system (RAS)

Answer 2

keeps you awake –> role in consciousness and alertness

• habituation - ignores repetitive stimuli
• damage –> coma

Question 3

nuclei and chemicals that promote wakefullness

Answer 3

• raphe nucleus –> serotonin
• locus cereleus –> NE
• tuberomamillary nucleus –> histamine
• periaquaductal grey –> dopamine
• tegmentum of pons –> ACh
• perifornical area –> orexin (narcolepsy if deficient)

Question 4

inhibitors initiating sleep

Answer 4

VLPO –> inhibitory feed; major player

• adenosine trigger VLPO
• muramyl, IL1
• prostaglandin D2 triggers VLPO
• delta sleep inducing peptide (not in body)
• protein/carb (high insulin, low orexin)
• excess Trp –> sleep disorders

Question 5

coffee/caffeine

Answer 5

prevents adenosine from binding to receptor

-adenosine signal for tired, low energy

Question 6

orthodox - NREM

Answer 6

• suppress respiration rate, CV, muscles

- more parasympathetic (vagus)

Question 7

paradoxical/REM

Answer 7

• dreaming, deep sleep, inhibit muscles
• faster respiration and HR
• high eye and brain activity

Question 8

REM role

Answer 8

increasing consolidation of memories

• higher with longer hr. of sleep
• more REM as child –> imagination and night terrors
• less REM with aging –> lose memory, awake easier with external stimuli

Question 9

stage 1 sleep

Answer 9

• wake up easily, light sleep
• eyes roll back in head
• hallucinations
• ALPHA waves

Question 10

stage 2 sleep

Answer 10

• light sleep, harder to awaken
• K complexes and sleep spindles
• alpha –> THETA waves
• dream fragments

Question 11

stage 3 sleep

Answer 11

• deeper sleep, harder to wake up
• increase respiration, temp, BP, HR
• relax muscles more
• low frequency THETA; some DELTA appear

Question 12

stage 4 sleep - slow wave sleep

Answer 12

• dreaming (night terrors) with REM
• sleep walk, talk, snore
• hard to awaken, muscles very relaxed
• vital signs low
• involves solitary nucleus
• high amplitude DELTA waves

Question 13

REM

Answer 13

• oscillation of eyes
• sawtooth THETA waves
• increase HR and respiration rate
• muscles still paralyzed
• hard to awaken with external stimuli, easier to awaken on own
• dreams common

Question 14

role of EtOH on REM

Answer 14

inhibits the REM –> makes you more tired the next morning

-only activates GABA

Question 15

insomnia

Answer 15

sleep onset delay

-restless leg syndrome

Question 16

parasomnia

Answer 16

abnormal patterns of sleep

1. during NREM
   - night terrors and sleep walking
2. during REM
   - sleep behavior disorder –> acting out dreams
   - nightmare disorder

Question 17

reticular excitatory area = RAS

Answer 17

• signal to thalamus –> brain
• transmission of pain
• suppression of signals
• active recall of memory from cerebral cortex
• inhibitory and excitatory area

Question 18

hormonal control of brain activity

Answer 18

• NE –> excitatory; role in REM
• serotonin –> excitatory or inhibitory; pain suppression and sleep
• gigantocellular neurons –> secrete ACh; waking up and excitatory

Question 19

portions of hypothalamus involved in emotions and behavior

Answer 19

• lateral –> fear and rage; very passive with lesion
• ventromedial –> tranquility (calm), satiety; rage with lesion
• periventricular –> fear and punishment
• anterior and posterior –> sex drive

Question 20

role of NE in hypothalamus regulation during stress

Answer 20

solitary nucleus releases NE to stimulate PVN to release CRH –> + ACTH release –> give cortisol

Question 21

reward centers in the brain

Answer 21

• medial forebrain bundle

- medial and lateral VMN of thalamus

Question 22

punishment centers in brain

Answer 22

• central gray matter
• amygdala
• hippocampus

Question 23

tranquilizers

Answer 23

inhibit reward and punishment centers lowering reactivity

-habituation and facilitation

Question 24

hippocampus

Answer 24

• consolidation and declarative memory - processes social emotion
• does not store memory but needed to store elsewhere
• anterograde amnesia with damage

Question 25

amygdala functions

Answer 25

• link b/w stimuli and response
• conditioned fear (no stimuli present)
• many outputs and inputs
• outputs to cortex (experience and instruction), hippocampus (consolidate memory), hypothalamus (autonomic response and rage)
• cut amygdala nucleus or inhibit NMDA –> prevent fear memory
• sexual functions/changes
• fear (most common) –> different responses
• associated with basal ganglia –> either stimulatory (ballistic) or inhibitory (freezing)

Question 26

frontal cortex role in emotions

Answer 26

• filters emotional response - processing of rewards and punishments
• long term planning of emotions and actions (memory)

Question 27

Kluver-Bucy syndrome

Answer 27

temporal lobotomy or damage

• aggressive before
• calm but increased sexual desire after

Question 28

depression

Answer 28

• treat with serotonin uptake inhibitors

- cingulotomy relieves pain and depression