Lecture 6: Brain Arousal Systems

Question 1

Injuries to what areas often cause disruptions to consciousness?

Answer 1

Brainstem
Midbrain
Hypothalamus

Question 2

What is the role of serotonin?

Answer 2

Quiet Awareness

Question 3

What does dopamine do?

Answer 3

Cognitive Function
Motor Function
Emotion (pleasure)

Question 4

What NTs take one from a coma to Arousal/Wakefulness?

Answer 4

Acetylcholine and EAA

Question 5

Why is RAS not specific?

Answer 5

All sensory pathways converge at RAS and there is too much input - basically RAS is just an event detector

Question 6

What NTs take one from Arousal/Wakefulness to Awareness?

Answer 6

Norepinephrine

Serotonin

Question 7

What is the role of norepinephrine?

Answer 7

Startle and Alert (EEG Manifestation)

Question 8

What has to be damaged in cerebral cortex to cause comatose state?

Answer 8

Bilateral and massive damage

Question 9

Where can Acetylcholine be found?

Answer 9

Pedunculopontine Tegmental (PPT)
Laterodorsal Nuclei (LDT)

Question 10

What parts of of consciousness is missing in a coma?

Answer 10

Arousal and Awareness

EEG shows nothing

Question 11

Where do the dorsal pathways go?

Answer 11

Go to intralaminar nucleus of thalamus and then diffuse to rest of the brain

Question 12

How are oscillations created on EEG?

Answer 12

Dopamine + EAA release GABA???

Question 13

Where is dopamine found?

Answer 13

Ventral Tegmental Area

Substantia Nigra

Question 14

Between RAS and Parabrachial Nuclei, which one utilizes ventral pathway only?

Answer 14

Parabrachial Nuclei

Question 15

What is affected in patients with Alzheimer’s?

Answer 15

Cholinergic systems: slow mental processes and impaired memory formation

Question 16

Where can EAA be found?

Answer 16

Reticular Activating System (RAS)

Parabrachial Nuclei

Question 17

For arousal, what pathways are used?

Answer 17

Both dorsal and ventral

Question 18

Where do the ventral pathways go?

Answer 18

Skips thalamus via basal forebrain and hypothalamus and then diffuse to rest of the brain

Question 19

What can treat some people in a persistent vegetative state

Answer 19

Levodopa

Question 20

What parts of of consciousness is missing in a persistent vegetative state?

Answer 20

Awareness (Arousal is present on EEG)

Question 21

What NT takes one from Awareness to Alertness?

Answer 21

Dopamine

Question 22

What are the two parts of consciousness?

Answer 22

Arousal (being awake)

Awareness (conscious processing of inputs)

Question 23

What causes spindle-like discharges during sleep?

Answer 23

Thalamocortical neurons are hyperpolarized and show occasional bursts

Question 24

What happens if there is damage to PPT/LDT?

Answer 24

Severe Cognitive Defects

Slowing of Cortical processes

Question 25

What is the status of cortical neurons in a persistent vegetative state?

Answer 25

Hyperpolarized (30 mv below threshold)