Sleep and consciousness Flashcards
Describe the organisation of neurons in the brain cortex [1]
Organized in layers, or laminas, parallel to the surface of the brain
Which lamina layer predominately generates the current that EEGs detect
Layer 1
Layer 2
Layer 3
Layer 4
Layer 5
Which lamina layer predominately generates the current that EEGs detect
Layer 1
Layer 2
Layer 3
Layer 4
Layer 5
What are EEG recordings detecting when placed on the head? [1]
EEGs detect the summated post synaptic potentials create a field with positive and negative poles (dipole). The dipole vector, or direction of energy flow, is parallel to the orientation of the pyramidal cells generating the activity
EPSP (Excitatory postsynaptic potential; Na+ & K+ entering cell and source of current into extracellular medium)
Versus
IPSP (inhibitory postsynaptic potential; flow of negatively charged chloride ions entering the cell and source of current in the extracellular medium)
Most of the electrical activity recorded in the EEG is generated by pyramidal neurons similarly oriented in space with synchronous firing created from which areas? [2]
created by thalamo-cortical oscillations:
- thalamic input from the sensory systems
- non-specific thalamic input generates rhythmic oscillations
In wakefulness EEG is more [desynchronized / synchronized]?
In sleep the EEG is more [desynchronized / synchronized]?.
In wakefulness EEG is more desynchronized.
In sleep the EEG is more synchronized.
Which area of the brain alters the frequency / desynchronizes the of EEG during wakefulness? [1]
Reticular activating system
Which of the following EEG frequencies are responsbile for ‘active wakefullness & REM sleep’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are responsbile for ‘active wakefullness & REM sleep’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are active during for ‘sleep & meditation’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are active during for ‘sleep & meditation’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are active during ‘active information processing’’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are active during ‘active information processing’’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are occur while resting with the eyes closed’?
Gamma
Beta
Alpha
Theta
Delta
Which of the following EEG frequencies are occur while resting with the eyes closed’?
Gamma
Beta
Alpha
Theta
Delta
Which are the following EEG frequencies?
EEG
Which of the following is eyes closed and eyes open?
A: eyes closed
B: eyes opened
What does it mean physiologically if the EEG shows a ‘desynchronised’ appearance versus ‘synchronised’ appearance? [1]
Desynchronised:
* If individual neurons (eg A,B, C) are firing out of phase with each other
Synchronised:
* If individual neurons (eg A,B, C) are firing in phase with each other
* EEG shows high amplitude ‘slow wave’ appearance
Describe how EEG recordings change from awakefullness to sleep and how these change during sleep. [4]
Awake: high frequency, unsynchronised EEGs
Stage 1: theta waves
Stage 2: sleep spindles
Stage 3 - 4: delta waves
REM: low voltage, random fast sawtooth waves
Then repeats 4 or 5 times per night
Describe EEGs in epilepsy patients during an epileptic attack [1]
Epilepsy – waves are hypersynchronized: very high amplitude: causes patients to lose consciousness.