Reticular Formation + Consciousness Flashcards

1
Q

What does Arousal mean

A

State of being oriented towards a goal or avoiding a noxious stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does consciousness mean

A

Awareness of internal or external environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Reticular Formation

A

Population of specialised interneurones in brainstem involved in consciousness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the functions of Reticular Formation

A
Sleep 
Cardiorespiratory control 
Autonomic control 
Motor control 
Consciousness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the sources of input of reticular formation

A

Cortex

All sensory systems: special, visceral, somatosensory, nociceptive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the sites of output of reticular formation

A

Hypothalamus
Thalamus
Basal forebrain nuclei
Spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is reticular activating system

A

Part of the reticular formation devoted to arousal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the RAS consist of

A

Ascending stimulatory neurones to cortex:
Cholinergic to hypothalamus, histaminergic to cortex
Cholinergic to basal forebrain nuclei, cholinergic to cortex
Cholinergic to Thalamus, glutamatergic to cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does RAS cause arousal

A

Ascending stimulatory neurones stimulate cortex
Set up positive feedback bw cortex and RF
Arousal occurs in all or nothing phenomenon
Either awake or asleep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of neuronal activity occurs in sleep

Why is this

A

Synchronous neuronal Activity

Neurones fire synchronously when deprived of sensory input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does electroencephalogram measure

A

Combined electrical activity of neurones in given part of cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the trend in EEG patterns during sleep

A

As you go down stages of sleep, increased amplitude and decreased frequency of EEG traces
Neurones go into synchrony

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the EEG show with each stage of sleep

A

Awake/R.E.M - Beta waves (50Hz)
Eyes closed - Alpha waves (10Hz)
Stage 1 - Theta waves (5Hz) in background of alpha waves
Stage 2/3 - K complexes in background of theta waves
Stage 4 - Gamma waves (1Hz) (intrinsic rate of cortex when all sensory input removed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the mechanism of sleep

A

Inhibition of RAS by inhibitory GABAergic neurones
Loss of cortical stimulation
Loss of positive feedback
Assisted by removal of sensory inputs (e.g. close eyes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is R.E.M. sleep

A

Rapid eye movement sleep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens in R.E.M. sleep

A

High cortical activity - dreams
Muscle paralysis - strong inhibition of thalamus
Eye movements and cranial nerve spared - bruxism
Autonomic effects - direction, loss of thermoregulation

17
Q

What are the functions of sleep

A

Bodily repair
Memory: short term to long term consolidation
Clear extracellular debris (Alzheimers and amyloid)

18
Q

What are the types disorders of sleep

A

Insomnia
Narcolepsy
Sleep apnoea

19
Q

What is insomnia

A

Difficulty sleeping/unsatisfactory sleep which may lead to daytime symptoms
Most often due to mental health issues/anxiety

20
Q

What is narcolepsy

A

Neurological condition; impaired regulation of sleep-wake cycle
Patient experiences extreme daytime tiredness, Sleep attacks, cataplexy (Muscle paralysis in response to strong emotion)

21
Q

What is sleep apnoea

A

Intermittent and repeated upper respiratory tract muscle relaxation during sleep
This causes arousal or lighter stages of sleep
Patient experiences unsatisfactory sleep and daytime tiredness

22
Q

What are disorders of consciousness

A

Brain death
Coma
Persistent vegetative state

23
Q

What is brain death

A

Widespread cortical and brainstem damage

Flat EEG

24
Q

What is coma

A

Widespread cortical and brainstem damage
Various EEG patterns
Not arousable to psychologically meaningful stimuli
No sleep wake cycle

25
Q

What is persistent vegetative state

A

Widespread cortex and brainstem damage
Various EEG patterns
Responsive to stimuli by brainstem reflexes, spontaneous eye opening
Sleep wake cycle detectable

26
Q

Is Locked-in syndrome a disorder of consciousness

A

No - it is a motor syndrome
Loss of somatic motor function from pons down, due to pontine/basilar artery occlusion
Consciousness preserved
Eye movement preserved

27
Q

How can you assess consciousness

A

Glasgow Coma Scale

28
Q

How is the Glasgow coma scale scored

A

Score out of 15, 3 being minimum, based on:
Eye opening
Motor response
Verbal response

29
Q

What are the levels of eye opening

A

Spontaneous
To speech
To pain
No response

30
Q

What are the levels of motor response

A
Follow instructions
Localises to pain
Withdraws to pain
Abnormal flexor response
Abnormal extensor response
No response
31
Q

What are the levels of verbal response

A
Oriented (appropriate + correct) 
Confused (appropriate + incorrect) 
Inappropriate words
Incomprehensible sounds 
No response