Lecture 4 - Food & Drugs Flashcards

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1
Q

Explain the (in)activation of neurotransmitters

A
  1. Blocking release of neurotransmitters
  2. Reuptake by axon terminals or glial cells for reuse
  3. Deactivated by enzymes
  4. Diffusion via blood
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2
Q

What 2 processes are part of ‘Blocking release of neurotransmitters’?

A
  1. Botulinium toxin (ACh) –> muscle paralysis
  2. Clozapine in Schizophrenia (lowers DA/dopamine)
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3
Q

What 3 processes are part of ‘reuptake by axon terminals or gliall cells for reuse’?

A
  1. Cocaine and speed delay reuptake norepinephrine (increases pleasure)
  2. Anti-depressants (prozac) block reuptake of Serotonin
  3. Lithium speeds reuptake (lowers dopamine)
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4
Q

What 2 processes are part of ‘deactivated by enzymes’?

A
  1. COMT-gene encodes an enzyme that modulates DA in the PFC
  2. Nerve gas (VX) destroys AChE
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5
Q

Why are neurotransmitters diffused by the blood?

A

So neurotransmitters can diffuse out of the synaptic cleft

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6
Q

What is dopamine associated with?

A
  1. Reward (ice-cream, promotions)
  2. Goal proximity (to-do lists, video games)
  3. Motivation (trouble in Parkinson’s)
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7
Q

What role does dopamine play in ADHD and Schizophrenia?

A
  1. ADHD: High Dopamine Transporter Density
    * Impulsive, increased cravings
    * Reduced inhibition
  2. Schizophrenia: Overactive dopamine
    * DA-antagonists (blockers) reduce hallucinations
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8
Q

What are the executive functions?

A
  1. Updating/Monitoring
  2. Switching/Shifting
  3. Inhibition
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9
Q

Wisconsin Card Sorting Task

A

A neuropsychological instrument used to measure the executive functions, reportedly sensitive to brain dysfunction affecting the frontal lobes

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10
Q

N-back task

A

Participants are presented with a sequence of stimuli (e.g., letters) one at a time and asked to compare the current stimulus to one presented n items prior in the sequence.

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11
Q

What 5 functions does Updating/Monitoring have

A
  1. Primarily -> Working memory
  2. Encode relevant incoming information
  3. Update/revise existing representations
  4. Manipulate representations
  5. Monitor for changes
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12
Q

Task Switching Paradigm

A

Performance in task switching is an important measure of cognitive flexibility. In task switching, participants randomly alternate between performances of two (or more) tasks, with an advance cue specifying the task to perform on the upcoming trial.

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13
Q

What 3 functions does Switching/Shifting have

A
  1. Engagement of a new/relevant task
  2. Disengagement from an old/irrelevant task
  3. Suppress proactive interference
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14
Q

Stop Signal Task

A

Participants are presented with an imperative stimulus and are asked to respond as fast as possible.

On a subset of trials, the imperative stimulus is followed by a second stimulus (the stop signal) that instructs participants to abort the response already initiated.

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15
Q

What function does Inhibition have

A

Supress irrelevant but dominant actions

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16
Q

What are dominant actions

A
  1. Learned habits
  2. Practiced actions or overlearned skills
  3. Personality traits or tendencies
17
Q

2 traits of the Nigrostriatal pathway

A
  1. Motor control
  2. Death of neurons in this pathway can result in Parkinson’s disease
18
Q

5 functions of the mesolimbic and mesocortical pathways

A
  1. Memory
  2. Motivation & emotional response
  3. Reward and desire
  4. Addiction
  5. Can cause hallucinations and schizophrenia if not functioning properly
19
Q

4 functions of tuberoinfundibular pathway

A
  1. hormonal regulation
  2. Maternal behavior
  3. pregnancy
  4. sensory processes
20
Q

High prefrontal DA leads to:

A

Cognitive stability
* Goal maintenancy
* Focussing
* Suppressing distraction
* Inflexible/insensitive

21
Q

Low prefrontal DA leads to:

A

Cognitive flexibility
* Flexibility - inhibition and switching
* Prone to distraction and interference

22
Q

What is associated with low cognitive performance?

A

High and low DA levels

23
Q

Which two types of medications can optimise our baseline dopamine levels?

A
  1. Stimulants
  2. Depressants
24
Q

What do the effect of drugs depend on?

A
  1. Type and difficulty of task
  2. Genetics predisposition
  3. Type of drug
  4. Dosage, consumption history
  5. Age, gender, disease, infection, immunity
25
Q

How does the COMT gene regulate dopamine in the PFC

A

Enzymes in the COMT gene inactivate released dopamine, thereby regulating its flux in the PFC.

26
Q

What 2 flavors of alleles does the COMT gene have?

A
  1. Val-Val (low DA)
  2. Met-Met (high DA)
27
Q

What are traits of Valine amino acid people

A
  • Warriors
  • Resilient to stress, relax quicker
28
Q

What are traits of Methionine people

A
  • More DA is not necessarily a good thing
  • worriers
  • Neurotic, less resilient to stress
  • Higher IQ, do well at school, creative
29
Q

WCST and Amphetamine

A
  1. Val-carriers are worse in sustained attention task
  2. Val improves with AMP
  3. Met-carriers show decline with AMP
30
Q

N-back task and Amphetamine

A

Val-Val
* No difference in accuracy with AMP
* Better PFC efficiency in AMP vs Placebo at all levels of load

Met-Met
* No difference in accuracy or efficiency with AMP at low load
* Low accuracy and low PFC efficiency in AMP vs Placebo at high load

31
Q

What is said about Inhibition and Dosage of Dopamine

A
  1. “… facilitating effects of stimulant drugs on inhibitory control are limited to a range of intermediate doses, above which improvement is no longer evident and impairing effects could possibly emerge”
  2. “Acute impairments of inhibitory mechanisms could compromise the ability to terminate drug-acquisition behavior leading to continued self-administration”
32
Q

What is Tyrosine?

A
  1. Precursor of Dopamine (and NE - Norepinephrine), naturally produced in body
  2. Source: apples, soy, chicke, fish, milk, spinach
  3. 1 hr after intake, DA levels go up. Half life = 2 hrs
  4. Can reverse mental decline and improve cognition in short-term
  5. Low TyrH expression in Parkinson’s
  6. Very difficult to overdose on TYR due to limited TyrH
  7. Safe to use as compared to performance enhancing supplements like ritalin
33
Q

What is serotonin?

A

‘Happy’ neurotransmitter

Associated with:
* OCD (reduced information processing)
* Sleep and mood
* Agression
* Lowers depression, autism and OCD
* High = serotonin syndrome

34
Q

What happens if you decrease serotonin?

A
  1. Less affiliative behavior (social/emotional bonding)
  2. Increased aggression
  3. Stronger response to unfairness
  4. Bias towards negative stimuli
35
Q

Tryptophan

A
  1. Alternative to serotonin drugs
  2. Precursor to serotonin and melatonin
  3. Not produced naturally in the body
  4. Source: salmon, poultry, eggs, spinach, nuts
  5. Half life = 2 hours
  6. Used for treating depression, anxiety and as a sleep aid
  7. Increase recall of positive material
  8. Decreases recognition of negative faces
36
Q

What does tryptophan induce?

A

A positive emotional bias