Principles Of Neuroscience Lecture 33 Drugs And The Brain

Question 0

What are some common psychoactive drugs?

Answer 0

Ethanol
Caffeine
Nicotine
Heroine
Cocaine
LSD
Valium
Prozac

Question 1

What are the general features of psychoactive drugs?

Answer 1

Small
Lipophilic
Resemble endogenous chemicals

Question 2

What are the two reasons that psychoactive drugs are used?

Answer 2

1. Pleasure - Hedonic drugs

2. Novelty - Psychadelic drugs

Question 3

What are the features of hedonic drugs?

Answer 3

• addictive

- tolerance exhibited by the users

Question 4

What are the features of psychedelic drugs?

Answer 4

• not as addictive as hedonic drugs

- not associated with tolerance

Question 5

What is interesting about tobacco?

Answer 5

It is highly addictive, however, the users do not show tolerance

Question 6

What aspects of brain function are affected by psychoactive drugs?

Answer 6

1. Behaviour
   - psychomotor agitations
2. Mental function

Question 7

Which functions of the PFC are altered by drugs?

Answer 7

• Motivation
• Perceived salience
• Emotional state
• Meaning and significance
• and vigilance
• Hedonic experience

Question 8

How do psychoactive drugs act?

Answer 8

Since they are small and lipophilic, they can cross the blood brain barrier

There are chemical homologous in the brain with their own receptors. Drugs bind to see receptors and alter the kinetics of neurons

Question 9

Describe what the research of opiate receptors lead to

Answer 9

Researchers were looking for the opioid receptor

Once they found it, they discovered the endogenous compound; endorphins

Question 10

What are the different classes of neurotransmitters?

Answer 10

Amino acids: glutamate, glycine, GABA
Small amines: noradrenaline, acetylcholine
Peptides

Question 11

What systems in the brain do psychoactive drugs work on?

Answer 11

The neuromodulatory systems

Question 12

What is the effect of LSD?

How does it act in the brain?

Answer 12

LSD causes hallucinations, “mind expanding” experiences

Serotonin agonist

Question 13

How do amphetamines and cocaine act in the brain?

Answer 13

These hijack the dopamine and noradrenaline systems

Question 14

Which general features seems to be always seen in addictive drugs?

Give an example

Answer 14

Enhancement of the dopaminergic signal transduction

Eg. nicotine acts on nAChR, leading to increased dopamine

Question 15

What are the four different types of connections between neurons?

Which does the neuromodulatory system use?

Answer 15

a. Simple - vision and motor control
b. Endocrine (big effect)
c. Amplification - ANS, preganglionic neurons controlling blood flow
d. Highly divergent (en passant) - the neuromodulatory systems

Question 16

Describe the subtle action of drugs

Answer 16

The drugs bind to the metabotropic receptors in the neuromodulatory systems and subtle alter the kinetics and excitability of the neuron

They do not vastly change the activity of the neurons

Question 17

Which sort of things does the serotonin system affect?

Answer 17

Mood
Appetite
Sleep

Question 18

What is the nucleus in the serotonin neuromodulatory system?

Answer 18

Raphe nucleus in the brain stem

Question 19

What is the nucleus in the dopamine neuromodulatory system?

Answer 19

Substantia nigra and Ventral tegmental area in the brain stem

Question 20

Describe the action of cocaine on one of the neuromodulatory systems

Answer 20

Cocaine increases the concentration of dopamine at the synapse in the nucleus accumbens

Question 21

Describe the action of heroin and nicotine on one of the neuromodulatory systems

Answer 21

Heroin and nicotine increase the action of the dopamine neurons in the VTA

Question 22

What are the different causes of hallucinations?

Answer 22

• Schizophrenia
• Side effect of medication
• Marajuana
• Crack cocaine

Question 23

Describe how seemingly different drugs can have similar effects

Answer 23

Marajuana and crack cocaine both cause hallucinations, even thought they are very different in function

Question 24

Why is alcohol the biggest drugs problem?

Answer 24

It accounts for the most reduction in life span and deaths as well as it costs 4.5 billion dollars, over twice the cost of all illicit drugs

Question 25

Describe the model of the effect of alcohol

Answer 25

Cause: volume drunk and patterns of drinking Acute effects: intoxication -> injury, acute social and psychological problems Chronic effects: dependence and toxicity -> chronic injury and social and psychological problems

Question 26

What are some chronic diseases caused by alcohol?

Answer 26

Liver disease Cancer Diabetes Neuro psychotic diseases (epilepsy, unipolar depression, PTSD, schizophrenia) Diseases associated with drinking during pregnancy

Question 27

What is the aetiology of FAS?

Answer 27

Alcohol crosses the blood brain barrier of the barrier; causing damage

Question 28

What are the external features of FAS?

Answer 28

``` Simian crease Flattened mid face Low nose arch Smooth upper lip Small eye openings Underdeveloped jaw ```

Question 29

What are the internal features of FAS?

Answer 29

Small brain, large gap between the hemispheres The prefrontal cortex is the most affected

Question 30

How is FAS diagnosed?

Answer 30

1. Decreased cognitive function: - academic - concentration, impulsiveness - learning disabilities - memory - maths skills - social perception - IQ below the 3rd pcentile 2. Anatomical features of the brain - microcephaly - hydrocephaly - callosal dysgenesis - migration abnormalities

Question 31

Where does alcohol act in the brain?

Answer 31

On GABA receptors (different site to benzodiazepine)

Question 32

What are the acute effects of alcohol acting in the brain? (4)

Answer 32

1. Potentiate as well as antagonise GABA's effects 2. Decrease GABA receptor density in the brain -> anxiety 3. Increases glutamate receptors in the hippocampus -> memory affected 4. Stimulates the release of serotonin (mood), endorphins (cravings) and dopamine (addiction)

Question 33

What are the chronic effects of alcohol on the brain?

Answer 33

- Reduced brain volume, especially the white matter and PFC - Thiamine deficiency - Liver disease (hallmark of complicated alcoholics)

Question 34

Describe what is meant by the coherent effects of psychoactive drugs

Answer 34

These drugs somehow do not cause massive disorganisation of brain activity, but have coherent, subtle effects on the brain

Question 35

Give examples of why neurotransmitters are not solely responsible for functions of the brain

Answer 35

Serotonin not solely responsible for mood | Dopamine not solely a molecule that produces reward and pleasure

Question 36

What are some Psychadelic drugs?

Answer 36

Marajuana, LSD