hefnawy - sleep and limbic system Flashcards
structures involved in sleep
suprachiasmatic nucleus (circadian rhythms) and pineal gland (melatonin)
reticular activation system (RAS)
keeps you awake –> role in consciousness and alertness
- habituation - ignores repetitive stimuli
- damage –> coma
nuclei and chemicals that promote wakefullness
- raphe nucleus –> serotonin
- locus cereleus –> NE
- tuberomamillary nucleus –> histamine
- periaquaductal grey –> dopamine
- tegmentum of pons –> ACh
- perifornical area –> orexin (narcolepsy if deficient)
inhibitors initiating sleep
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
coffee/caffeine
prevents adenosine from binding to receptor
-adenosine signal for tired, low energy
orthodox - NREM
- suppress respiration rate, CV, muscles
- more parasympathetic (vagus)
paradoxical/REM
- dreaming, deep sleep, inhibit muscles
- faster respiration and HR
- high eye and brain activity
REM role
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
stage 1 sleep
- wake up easily, light sleep
- eyes roll back in head
- hallucinations
- ALPHA waves
stage 2 sleep
- light sleep, harder to awaken
- K complexes and sleep spindles
- alpha –> THETA waves
- dream fragments
stage 3 sleep
- deeper sleep, harder to wake up
- increase respiration, temp, BP, HR
- relax muscles more
- low frequency THETA; some DELTA appear
stage 4 sleep - slow wave sleep
- 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
REM
- 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
role of EtOH on REM
inhibits the REM –> makes you more tired the next morning
-only activates GABA
insomnia
sleep onset delay
-restless leg syndrome
parasomnia
abnormal patterns of sleep
- during NREM
- night terrors and sleep walking - during REM
- sleep behavior disorder –> acting out dreams
- nightmare disorder
reticular excitatory area = RAS
- signal to thalamus –> brain
- transmission of pain
- suppression of signals
- active recall of memory from cerebral cortex
- inhibitory and excitatory area
hormonal control of brain activity
- NE –> excitatory; role in REM
- serotonin –> excitatory or inhibitory; pain suppression and sleep
- gigantocellular neurons –> secrete ACh; waking up and excitatory
portions of hypothalamus involved in emotions and behavior
- lateral –> fear and rage; very passive with lesion
- ventromedial –> tranquility (calm), satiety; rage with lesion
- periventricular –> fear and punishment
- anterior and posterior –> sex drive
role of NE in hypothalamus regulation during stress
solitary nucleus releases NE to stimulate PVN to release CRH –> + ACTH release –> give cortisol
reward centers in the brain
- medial forebrain bundle
- medial and lateral VMN of thalamus
punishment centers in brain
- central gray matter
- amygdala
- hippocampus
tranquilizers
inhibit reward and punishment centers lowering reactivity
-habituation and facilitation
hippocampus
- consolidation and declarative memory - processes social emotion
- does not store memory but needed to store elsewhere
- anterograde amnesia with damage
amygdala functions
- 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)
frontal cortex role in emotions
- filters emotional response - processing of rewards and punishments
- long term planning of emotions and actions (memory)
Kluver-Bucy syndrome
temporal lobotomy or damage
- aggressive before
- calm but increased sexual desire after
depression
- treat with serotonin uptake inhibitors
- cingulotomy relieves pain and depression
