Sleep Flashcards
Why do we sleep?
Most common answers: Energy conservation, predator avoidance, body restoration, memory consolidation
What does an EEG do?
measures EPSPS from a population of neurons near the surface of the brain
Describe the patterns seen in an EEG reading with their component frequencies
alpha- 8-12 Hz-occur during relaxed wakefullness
beta-12.5-30Hz
theta-4-7Hz-in children OR during meditative, drowsy, sleepy adults
gamma-greater than 30hz
delta-1-4Hz-deep sleep, coma, anesthesia
describe stage one sleep
slowing of heart rate, reduction of muscle tension, closed eyes may roll around, usually lasts several minutes. characterized by small amplitude eeg waves orf irregular frequency as well as sharp waves called vertex spikes
stage 2 sleep
defined by bursts of sleep spindles (12-14Hz) and k complexes. If awakened most people deny they were asleep
sleep spindle
14-18Hz wave seen in stage 2 sleep
K complex
sharp negative EEg reading. stage 2 sleep
Stage 3 sleep
characterized by large amplitude very slow waves (delta waves). sleep spindles continue as in stage 2. delta waves about once per second
stage 4 (otherwise known as stage three late)
similar to stage 3(early) but with even more delta waves. cortical activity begins to become synchronized. Hard to wake up here
REM sleep
completely relaxed, paralyzed muscles. small amplitude high-frequency acitvity similar to waking. Vivid dreams occur. brain stem inhibits motor neurons. heart rate and respiration is irregular.
What wave forms dominate wakefullness
fast frequency low amplitude 15-20Hz. known as beta activity or desynchronized EEG.
and alpha rhythms which occur during relaxation. oscillate at 8-12Hz
describe a typical nights sleep
7-8 hours, 45-50% stage 2, 20% REM sleep, cycles last 90-110 minutes
When does the majority of SWS and REM sleep occur
SWS-cycles early in the night have more stage 3SWS
REM-later cycles have more REM
What are the functions of slow wave sleep
rest and repair
What is the outcome of sleep deprivatgion in rats
increased metabolic rate, lose weight, die in 19 days. Hinders immune system, most rats died of bacterial infection through sores
fatal familial insomnia
degeneration of thalamus which results in insomnia in mid life. die 7-24 months after inso9mnia begins
The locus coeruleus produces
NE (and its blue)
cholinergic nuclie prodcues _____ which arouses the ___
acetylcholine, cortex
Where is histamine producec and what does it do.
histamine is produced in the tuberomammilary nucleus. There are projections to the cortex which are directly arousing
What is adenosine
a nucleoside neurotransmitter
what doed adenosine do
it has inhibitory effects. Accumulation in one area prmotes increased delta activity in that area during the next night’s sleep
study study picutres of neural conrl
…and shit
during REM slee, acetylcholine neuronal activity increases. where?
peribrachial area
what does ACh in the peribrachial area cause
PGO waves and cortical arousal
activates neurons in the MPRF which in turn… activates neurons
on the basal forebrain
