19 Brain Arousal Systems - B

Question 1

What are the 2 parts of conciousness

Answer 1

Arousal and awareness

Question 2

What are examples of arousal

Answer 2

Sleep and wakefulness

Question 3

What is a minimally conscious state

Answer 3

Reproducible evidence of awareness exists but communication is limited

Sleep wake cycles can be seen on EEG

Question 4

What is a persistent vegetative state

Answer 4

• pts eyes open and close
• they can track objects
• they can chew and swallow
• do not respond to auditory stimuli, pain, hunger

Good example of arousal but no awareness

Question 5

What is a coma

Answer 5

Deeply unconscious and displays unresponsiveness to stimuli

May display reflexes

Question 6

What marks irreversible brain death

Answer 6

No EEG activity recorded

Question 7

What is required for arousal and awareness

Answer 7

Cortical function

Question 8

Disruptions in consciousness arise from

Answer 8

Subcortical lesions

• brainstem
• midbrain
• hypothalamus

Question 9

What are the excitatory amino acid arousal systems

Answer 9

• reticular activating system (RAS)

- parabracial nuclei (PBN)

Question 10

What are the cholinergic arousal systems

Answer 10

Pedunculopontine tegmental and laterodorsal nuclei (PPT/LDT)

Question 11

What are the noradrenergic arousal systems

Answer 11

Locus coeruleus (LC)

Question 12

What are the serotonergic arousal systems

Answer 12

Raphe nuclei (RN)

Question 13

What are the dopaminergic arousal systems

Answer 13

Ventral tegmental area (VTA)

Question 14

What does the RAS project to

Answer 14

• hypothalamus
• thalamus
• cortex

Question 15

What tract does the RAS descend to in spinal cord

Answer 15

Reticulospinal tract

Question 16

What is the function of the RAS

Answer 16

• regulates arousal and consciousness
• all ascending (sensory) info goes through it
• modal specificity is lost because all pathways are converged
• USES GLUTAMINE

Question 17

The ascending RAS has 2 outputs. Where do they go and what do they do

Answer 17

Ventral
-goes to cortex or through hypothalamus and then to cortex

Dorsal
-through thalamus and then diffuses to cortex

Question 18

What is the parabrachial nuclei complex

Answer 18

Different neurons that play a role in promoting wakefulness through cortical activation \

Question 19

What does the parabrachial nuclei do

Answer 19

Generates respiration patterns during waking state

• amygdala activation of PBN causes hyperventilation during anxiety
• USES GLUTAMINE

Question 20

What are the PBN outputs

Answer 20

Ventral pathway (like RAS)
-goes straight to cortex or through hypothalamus to cortex

Question 21

How is the PBN and RAS similar

Answer 21

Both use EAA glutamate

-RAS has interneurons that release GABA and ACh

Question 22

Excitable amino acids are crucial to

Answer 22

Baseline excitation of cortical activity

Question 23

What are the outputs of the PPT and LDT

Answer 23

Dorsal (to thalamus then cortex) or Ventral (to cortex or hypothalamus and then cortex)

Question 24

What is the major neurotransmitter over the PPT/LDT

Answer 24

ACh

Question 25

What nuclei are the primary cause wakefulness and REM sleep

Answer 25

Cholinergic nuclei

Question 26

Also involved in wakefulness and REM sleep (beside LDT/PPT)

Answer 26

- noradrenergic neurons of locus ceruleus - serotonergic neurons of raphe nuclei - histaminergic neurons of the tuberomammilary nuclei (of hypothalamus)

Question 27

What does antihistamines inhibit in the brain

Answer 27

TMN network to make you drowsy

Question 28

In addition to sleep, cholinergic neurons also

Answer 28

Provide baseline excitation that is crucial to cortical activity

Question 29

What is the locus coeruleus

Answer 29

Noradrenergic neurons that function in the alerting response Being startled is also associated with this system

Question 30

What are the functions of the locus coeruleus

Answer 30

- startle and alerting responses - sleep-wake cycles - behavioral vigilance

Question 31

What are the ascending outputs of the locus coerulus

Answer 31

Dorsal and ventral pathways used by RAS Becomes the dorsal adrenergic bundle

Question 32

What is the descending output of locus coeruleus

Answer 32

Sensory modulation

Question 33

What are the outputs used by the RAS

Answer 33

Dorsal and ventral (same as RAS)

Question 34

What does the raphe nuclei use

Answer 34

Serotonin (basis of SSRI anti-depressants)

Question 35

What are the functions of the raphe nuclei

Answer 35

- quiet awareness - mood and affect - modulation of pain

Question 36

The ventral tegmental nuclei uses what NT

Answer 36

Dopamine

Question 37

The VTN provides input for

Answer 37

Cognitive functions Motor activity Emotions

Question 38

Intracortical neurons relating to the RAS use GABA to create oscillations seen in the EEG as

Answer 38

Spindle-like discharges

Question 39

Hyperpolarization of dorsal and ventral pathways occurs during

Answer 39

Low activity states like sleeping

Question 40

During PVS (persistent vegetative state) cortical neurons are

Answer 40

Hyperpolarized Levadopa has been shown in some to increase cognitive function

Question 41

During sleep, the thalamocortical neurons are __________ and occasionally show

Answer 41

Hyperpolarized; spindle-like discharges

Question 42

Hyperpolarization of the thalamic arousal system shuts of

Answer 42

Cortex from the excitatory influence during deepest levels of sleep

Question 43

Alertness is primarily done by what NT

Answer 43

Dopamine

Question 44

Awareness is done primarily by what NT

Answer 44

Norepinephrine and serotonin (5HT)

Question 45

Arousal is primarily done by what NT

Answer 45

EAA (glutamate) and ACh