Lecture 4 Noradrenaline Arousal, Anxiety, and Decision-Making/ADHD

Question 1

What is noradrenaline (NA) synthesized from?

Answer 1

Tyrosine, an amino acid found in food.

Question 2

Where is noradrenaline released from in the brain?

Answer 2

Neurons in the Locus Coeruleus (LC) in pons

Question 3

What events does NA increase arousal for?

Answer 3

Evolutionarily important events (4 F’s: Fight, Flight, Freeze, Fornicate).

Question 4

What happens with high levels of NA/LC activity?

Answer 4

Associated with stress, anxiety, and panic attacks.

Question 5

What role does NA play in decision-making?

Answer 5

Helps consolidate decisions and balance between exploitation and exploration.

Question 6

What bodily indicator can reflect NA release?

Answer 6

Pupil dilation.

Question 7

How is adrenaline synthesized from noradrenaline?

Answer 7

One extra synthesis step in the adrenal gland (medulla).

Question 8

How is noradrenaline broken down?

Answer 8

Adrenaline: a single synthesis step in the medulla (inner part) of the adrenal gland
Inactive metabolite: the breakdown enzyme monoamine oxidase (MAO) converts active noradrenaline (as well as other monoamines) into inactive metabolite.

Question 9

What nervous system is NA a part of?

Answer 9

Sympathetic nervous system 交感神经系统
(fight or flight response).

Question 10

What are the main roles of noradrenaline?

Answer 10

• Arousal,
• vigilance,
• anxiety,
• reward,
• memory consolidation,
• exploitation vs exploration.

Question 11

How many neurons does the Locus Coeruleus have approximately?

Answer 11

Around 30,000 neurons.

Question 12

What is the Locus Coeruleus (LC)?

Answer 12

A small nucleus in the brainstem that releases noradrenaline.

Question 13

When do LC neurons fire most rapidly?

Answer 13

After a transient noxious or extremely positive stimulus.

Question 14

When are LC neurons mostly silent?

Answer 14

During REM sleep.

Question 15

What are the 4F’s triggered by high LC/NA activity?

Answer 15

Fight, Flight, Freeze, Fornicate.

Question 16

What is stress in terms of LC/NA activity?

Answer 16

Sustained LC/NA activity due to ongoing environmental factors (social, emotional, physical etc).

Question 17

What is anxiety in terms of LC/NA activity?

Answer 17

Excessive, irrational worry lasting for over 6 months.

Question 18

What are panic attacks believed to reflect?

Answer 18

Sudden spikes of LC/NA activity.

Question 19

What are possible triggers for panic attacks?

Answer 19

• Random events,
• internal thoughts
• learned associations (e.g., PTSD).

Question 20

What is the stress-performance relationship shaped like?

Answer 20

An inverted U: too little or too much stress impairs function.

Question 21

What concept aligns with the stress-performance curve?

Answer 21

Flow Psychology (Mihaly Csikszentmihalyi).

Question 22

What does NA do at moderate levels of LC activity?

Answer 22

Acts to consolidate decisions.

Question 23

What is exploitation vs. exploration in decision making?

Answer 23

Balancing using known rewards vs. searching for alternatives.

Question 24

When do LC neurons fire?

Answer 24

When a behavioral response is selected and executed.

Question 25

What happens after LC neurons fire?

Answer 25

They are temporarily inhibited to allow exploitation of the behavior.

Question 26

What does increased baseline LC firing cause?

Answer 26

Switching to new decisions (exploration).

Question 27

What is the result of low LC/NA activity?

Answer 27

Tiredness, vagueness, and poor performance.

Question 28

What is the result of high LC/NA activity?

Answer 28

Restlessness, stress, and poor performance.

Question 29

What LC/NA activity pattern is optimal for performance?

Answer 29

Moderate activity with large intermittent bursts.

Question 30

What determines the magnitude of LC neuron burst?

Answer 30

The salience or arousal level of a chosen behavioral alternative.

Question 31

What happens with larger LC neuron responses during high arousal?

Answer 31

More NA is released and distracting alternatives are suppressed.

Question 32

What can pupil dilation indicate?

Answer 32

Levels of noradrenaline release in the brain.

Question 33

When is pupil dilation unrelated to NA?

Answer 33

In response to light, which involves acetylcholine (ACh), not NA.

Question 34

What blocks ACh muscarinic receptors and causes dilation?

Answer 34

Atropine and belladonna.

Question 35

What does pupil dilation during perceptual rivalry suggest?

Answer 35

Switching and decision-making processes are linked to NA.

Question 36

What theoretical role does NA play in decision-making?

Answer 36

Balancing stability/exploitation and flexibility/exploration.

Question 37

Summarize NA's main functions.

Answer 37

Arousal, stress response, anxiety regulation, decision-making, pupil dilation, memory, attention.