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Flashcards in Brain Arousal Systems Deck (47)
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1
Q

What are the 2 parts to consciousness?

A

Arousal and awareness

2
Q

Neither awake or aware and no sleep cycles

A

Coma

3
Q

No evidence of awareness and physiologically sensed sleep cycles

A

Persistent vegetative state

4
Q

Ability to respond to simple commands and has wake and sleep cycles

A

Minimally conscious state

5
Q

What is the order of things from coma to alertness?

A

Coma
Arousal
Awareness
Alertness

6
Q

What region of the brain is critical for arousing and activating the cortex?

A

Brainstem

7
Q

Can patients in a coma have eye/head movements?

A

Occasionally

8
Q

What are the arousal systems?

A

EAA, cholinergic, noradrenergic, serotonergic, dopaminergic

9
Q

What are the 2 parts to the EAA arousal system?

A

Reticular Activating System (RAS) and Parabrachial nuclei

10
Q

What arousal systems MUST be present to move from a coma to a persistent vegetative state?

A

EAA - Reticular Activating System and Parabrachial nuclei

11
Q

What can aid the EAA in moving a pt from a coma to the persistent vegetative state but cannot excite the cortex enough on its own?

A

Cholinergic arousal system

12
Q

Once the EAA and even the Cholinergic arousal systems are active, what arousal systems move you more and more towards consciousness?

A

Noradrenergic, Serotonergic, and Dopaminergic

13
Q

If all arousal systems are active and functioning correctly what is the result?

A

Fully functional human

14
Q

Describe the Dorsal pathway?

A

Neurons synapse at the thalamus first

Then Neurons from there are sent to the cortex to synapse

15
Q

What are the neurons that travel from the thalamus to the cortex called?

A

Thalamo-cortical neurons

16
Q

What do thalamo-cortical neurons release, regardless of what synapsed at them?

A

EAA

17
Q

Describe the Ventral pathway?

A

Neurons go straight to the cortex to synapse

18
Q

What do neurons that travel using the ventral pathway release at the synapse?

A

Whatever they were carrying - (i.e. EAA, Ach, NE, 5HT..)

19
Q

Where is the Reticular Activating system (RAS) located?

A

Midbrain and medulla

20
Q

What does the RAS system receive?

A

ALL ascending sensory tracts, trigeminal, auditory and visual

21
Q

What pathways does the RAS system use?

A

Dorsal and ventral

22
Q

What does the RAS system release the the synapses?

A

EAA

23
Q

Where is the Parabrachial nuclei located?

A

Pons

24
Q

What does the parabrachial nuclei receive?

A

ALL sensory inputs from body

25
Q

What pathways does the parabrachial nuclei use?

A

ONLY the Ventral pathway

26
Q

What does the parabrachial nuclei release at the synapse?

A

EAA

27
Q

Where is the cholinergic arousal system located?

A

Pons

28
Q

What are the 2 nuclei within the cholinergic system?

A

Pedunculopontine tegmental (PPT) and Laterodorsal (LDT)

29
Q

What pathways does the cholinergic system use?

A

BOTH the dorsal and ventral pathways

30
Q

What NT is released from the cholinergic system synapses?

A

ACETYLCHOLINE

31
Q

What does damage to the cholinergic system produce?

A

Will NOT result in a coma; but will result in progressively decreasing cortical processes and severe cognitive deficits

32
Q

Where is norepinephrine located?

A

Locus Ceruleus (in pons)

33
Q

What does the norepinephrine arousal system receive?

A

Sensory information that has already underdone some neural processing = more specific info

34
Q

What pathways for output does the norepinephrine system use?

A

BOTH dorsal and ventral pathways

35
Q

What does the norepinephrine system do?

A

Responsible for producing the startle/alertness response on an EEG

36
Q

Where is the serotonergic arousal system located?

A

Raphe nuclei

37
Q

What does the serotonergic system receive?

A

Sensory inputs from fine proprioception and trigeminal

38
Q

What pathways does the serotonergic system use?

A

BOTH dorsal and ventral pathways

39
Q

What does the serotonergic pathway do?

A

Contributes to a quiet awareness

40
Q

Where is the dopaminergic arousal system located?

A

Ventral tegmental area

41
Q

Describe how the EEG waves arise using the dorsal pathway?

A
  • Thalamo-cortical neurons can synapse on to -intracortical neurons
  • Intracortical neurons release GABA
  • GABA is an inhibitory AA
  • -First: excitation; Next: inhibtion = AP then no AP!
42
Q

What is the non-specific nuclei of the thalamus where dorsal pathway neurons can synapse called?

A

Intralaminar

43
Q

During sleep, what happens to thalamo-cortical neurons?

A

They are hyperpolarized which cuts cortex off from excitatory influence during sleep!

44
Q

What is needed to move from a coma to an arousal/wakeful state?

A

EAA / Ach - but mostly EAA

45
Q

What is needed to move from an arousal/wakeful state to a state of awareness?

A

NE and 5HT

46
Q

What is needed to move from a state of awareness to a state of alertness?

A

Dopamine

47
Q

Is the information that is relayed to the RAS, parabrachial nuclei or cholinergic systems specific?

A

NO; just know that something is happening