Variations in Consciousness (Sleep)

Question 1

What are Eletrocephalogram (EEG), Electrooculogram (EOG) and Electromyogram (EMG) and how do they all measure sleep?

Answer 1

EEG = Brain waves, measures activity on the surface of the cerebral hemispheres.

EOG = Eye movements

EMG = Muscle tension, placed on the chin, showing voluntary movement.

Question 2

What are the core features of an EEG?

Answer 2

electrodes placed on the scalp to detect and measure patterns of electrical activity in the brain.

Amplifies electric potentials occurring in many thousands of neurons.

Question 3

What are the collective stages of patterns of sleep called?

Answer 3

Non-rem sleep.

Question 4

What are beta waves?

Answer 4

They are waves that show on an EEG when we are awake.

Question 5

What happens when we become drowsy?

Answer 5

Beta waves slowly turn into alpha ways on the EEG pattern.

Question 6

What happens in Stage 1 of sleep?

Answer 6

Shift from Beta and Alpha waves into Theta waves.

Question 7

What happens in stage 2 of sleep?

Answer 7

Rapid bursts of high frequency waves called a sleep spindles.

K complexes - massive jumps in frequencies. (muscular contraction)

Question 8

What happens at stage 3 of sleep?

Answer 8

The beginning of delta waves.

Question 9

What happens at stage 4 sleep?

Answer 9

Exclusively delta wave activity.

High amplitude, low frequency, long slow patterns of electrical activity in the brain.

Question 10

What is slow wave sleep?

Answer 10

This is a combination of stage 3 and 4, reflective of high amplitude low frequency delta wave activity.

Question 11

What is REM sleep?

Answer 11

Paradoxical sleep.
A period of sleep where EEG is emitting similar tomography of awake frequencies.

Huge shifts on the EMG and EOG (rapid eye).

Almost a complete absence of muscular movement, almost paralysed during REM sleep.

We collectively spend 1 1/2 to 2 hours a night in REM.

Question 12

What are some neuro-conscious perspectives on dreaming and sleep amnesia?

Answer 12

Our brain try’s to sustain reality, so doesn’t store dreams, meaning memories aren’t consolidated after dreams.

During rem we have dreaming traits of colours, visual patterns and distortions.

Question 13

What are some age-related changes in REM?

Answer 13

Percentage of time in REM differs depending on age. Infants spend a lot of time in REM.

Hypothesis that REM forms a particular developmental function in the brain, possible synapse growth.

Question 14

What does the superchiasmatic nucleus have to do with circadian rhythm?

Answer 14

As the circadian rhythm is entrained to light and exposure sets it every day, the SN helps this process and entrain our rhythm.

Question 15

What is the retinohypothalamic pathway?

Answer 15

Light into nucleus - Hits the retina - travels down the optic nerve into the optic chiasm - becomes optic tract from the chiasm to the thalamus.

Question 16

What happens to circadian rhythm if someone damages their optic nerves?

Answer 16

input to the superchiasmatic nucleus changes the normal cycle, it becomes free running.

Question 17

What happens to someones circadian rhythm when there is damage to the optic tracts and visual cortex?

Answer 17

There is no problem with circadian rhythm regulation, cycle remains in tact as the retina and optic nerve can still function.

Question 18

What is important about the superchiasmatic nucleus?

Answer 18

It is critical to circadian rhythm.

Question 19

What are some neural systems involved in sleep?

Answer 19

Basal forebrain region in ventral frontal lobe may be responsible for inducing SWS

The reticular formation in the brain stem may be responsible for activation / waking the brain from sleep

The pons (REM)
Send a signal up via the thalamus to the cortex
Potential activation in those areas due to dreaming
Sends a signal down to the spinal cord which creates muscle paralysis.

Question 20

What are some theories of functions of sleep?

Answer 20

Restoration and recovery of bodily systems 
Energy conservation 
Memory consolidation 
Protection from predation
Brain development

Question 21

What are some common sleep disorders?

Answer 21

Insomnia 
Sleep apnoea 
Somnambulism
Night Terrors 
REM sleep behaviour disorder 
Narcolepsy