Variations in Consciousness (Sleep) Flashcards
What are Eletrocephalogram (EEG), Electrooculogram (EOG) and Electromyogram (EMG) and how do they all measure sleep?
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.
What are the core features of an EEG?
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.
What are the collective stages of patterns of sleep called?
Non-rem sleep.
What are beta waves?
They are waves that show on an EEG when we are awake.
What happens when we become drowsy?
Beta waves slowly turn into alpha ways on the EEG pattern.
What happens in Stage 1 of sleep?
Shift from Beta and Alpha waves into Theta waves.
What happens in stage 2 of sleep?
Rapid bursts of high frequency waves called a sleep spindles.
K complexes - massive jumps in frequencies. (muscular contraction)
What happens at stage 3 of sleep?
The beginning of delta waves.
What happens at stage 4 sleep?
Exclusively delta wave activity.
High amplitude, low frequency, long slow patterns of electrical activity in the brain.
What is slow wave sleep?
This is a combination of stage 3 and 4, reflective of high amplitude low frequency delta wave activity.
What is REM sleep?
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.
What are some neuro-conscious perspectives on dreaming and sleep amnesia?
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.
What are some age-related changes in REM?
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.
What does the superchiasmatic nucleus have to do with circadian rhythm?
As the circadian rhythm is entrained to light and exposure sets it every day, the SN helps this process and entrain our rhythm.
What is the retinohypothalamic pathway?
Light into nucleus - Hits the retina - travels down the optic nerve into the optic chiasm - becomes optic tract from the chiasm to the thalamus.
What happens to circadian rhythm if someone damages their optic nerves?
input to the superchiasmatic nucleus changes the normal cycle, it becomes free running.
What happens to someones circadian rhythm when there is damage to the optic tracts and visual cortex?
There is no problem with circadian rhythm regulation, cycle remains in tact as the retina and optic nerve can still function.
What is important about the superchiasmatic nucleus?
It is critical to circadian rhythm.
What are some neural systems involved in sleep?
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.
What are some theories of functions of sleep?
Restoration and recovery of bodily systems Energy conservation Memory consolidation Protection from predation Brain development
What are some common sleep disorders?
Insomnia Sleep apnoea Somnambulism Night Terrors REM sleep behaviour disorder Narcolepsy
