Brain Rhythms and Sleep 1

Question 1

brain rhythms

what are all brain rhythms characterised by?

think patterns and rates of patterns

Answer 1

by periodic re-occurrence of similar patterns at a relatively constant rate

Question 2

oscillations in the cerebral cortex

what waves are prominent in stage 1 of N-REM sleep

Answer 2

theta waves

Question 3

oscillations in the cerebral cortex

what are found in stage 2 of sleep in an EEG and what are they used for

Answer 3

-sleep spindles

• used to transfer info from short term memory to long term memory

Question 4

oscillations in the cerebral cortex

what waves are prominent in stage 3 and 4 of N-REM sleep

Answer 4

Delta waves

Question 5

oscillations in the cerebral cortex

what waves are prominent in REM sleep

Answer 5

Low-voltage, high frequency waves (similar to beta waves when awake)

Question 6

recording oscillations in cerebral cortex

what are features of the electroencephalogram (EEG)

think cortical activity, how it can effect a patient and neurological conditions

Answer 6

• measurement of generalized cortical activity
• non-invasive and painless
• can diagnose neurological conditions like epilepsy and sleep disorders

Question 7

EEG

what does the EEG record?

think electric fields, synapses and cells in cerebral cortex

Answer 7

records small electric fields generated by synaptic currents in pyramidal cells in cerebral cortex

Question 8

EEG

why do larger EEGs occur when asleep/ in deep sleep?

think type of firing

Answer 8

there is more synchronous firing of neurons (this usually only happens during sleep)

Question 9

what drives brain oscillations

what 2 ways can brain oscillations be driven?

Answer 9

1. rhythms can be led by a pacemaker (synchronous firing)
2. arise from collective behaviour of all participants

Question 10

what drives brain oscillations

what is a powerful pacemaker that can effect the cortex?

Answer 10

the Thalamus

Question 11

what drives brain oscillations

outline how the thalamus acts as a pacemaker for the cortex

think thalmocortical axons, excitation and oscillation of cells

Answer 11

1. Thalamus use thalmocortical axons to communicate with cortex
2. this excites cortical neurons
3. cortical cells will oscillate to the same rhythm as thalamus

Question 12

circadian rhythm

what does circadian rhythm do apart from modulate sleep wake cycle

Answer 12

• schedules thinks like temperature, hormone release, feeding, metabolism, drinking, behaviour

Question 13

circadian rhythms

what is the circadian rhythm regulated by

Answer 13

the Suprachiasmatic nucleus

Question 14

Circadian rhythms

outline the Suprachiasmatic nucleus (SCN) pathway

think light, time and effects

Answer 14

1. light sensitive input pathway
2. Clock (SCN)
3. output pathway

Question 15

circadian rhythm and the sleep wake cycle

define sleep

Answer 15

readily reversible state of reduced responsiveness and interaction with the environment

Question 16

hypnograms of adult sleep

what type of sleep increases in duration during sleep

Answer 16

REM sleep

Question 17

Stages of sleep

outline stage 1 of N-REM sleep

think types of waves involved,how regular and type of eye movement and length of time it lasts

Answer 17

transitional sleep full of alpha rhythms/waves that become less regular as you eyes start to make slow, rolling movement.

only lasts a few mins

Question 18

stages of sleep

outline stage 2 of N-REM sleep

think frequency of sleep spindles in Hz, type of waves and their amplitude and what generates them, effects on eye movement and time it lasts

Answer 18

deeper than stage one, and includes occasional 8-14 Hz sleep spindles and high-amplitude K-complex waves generated by a thalamic pacemaker. eye movements almost cease

lasts 5-15 mins

Question 19

stages of sleep

outline stage 3 of N-REM

think type of waves and eye/body movement

Answer 19

large amplitude, slow delta rhythms/waves. eye and body movement absent.

Question 20

stages of sleep

outline stage 4 of N-REM

think type of EEG rhythm observed, the waves’ frequency in Hz and how long it lasts

Answer 20

deepest stage of sleep. Large EEg delta rhythms of 2Hz or less

lasts between 30-40 mins

Question 21

stages of sleep

Outline REM sleep

think eye movement, type of EEG rhythms and when REM occurs

Answer 21

frequent eye movements, fast EEG rhythms/waves.

sleep will lighten from stage 4 to 2 for about 15 mins before entering brief period of REM

Question 22

stages of sleep

what happens to NREM and REM during the night progresses

Answer 22

general reduction in NREM and sleep and increase in REM

Question 23

physiological changes during N-REM and REM sleep

what are 2 physiological changes during N-REM sleep

think HR, BP, RR and muscles

Answer 23

1. steady HR, BP and Repsiration rate
2. Muscles relaxed

Question 24

physiological changes during N-REM and REM sleep

what are 2 physiological changes in REM sleep

think HR, BP and RR and muscles

Answer 24

1. Fluctuating HR, BP and respiration rate
2. skeletal muscles PROFOUNDLY relaxed

Question 25

Sleep and memory

outline how sleep aids memory before learning

think hippocampus, file-transfer and memory consolidation

Answer 25

1. hippocampus has limited stoage capacity
2. sleep takes info from hippocampus to nearby cortices (file-transfer mechanisms)
3. this frees up short term memory and makes prior memories more permenant (memory consolidation)

Question 26

sleep and memory

what time of sleep is rich in NREM?

Answer 26

early night sleeps

Question 27

sleep and memory

what is NREM useful for

think factual information, forgetting things, information recovery

Answer 27

• useful for consolidating Factual, textbook like information
• useful for forgetting information we no longer need
• useful for recovering information you couldnt retrieve before sleep

Question 28

sleep and memory

what is the main benefit of REM sleep

Answer 28

• helps brain gather disparate sets of knowledge fostering creativity and better problem solving

Question 29

Ended