Central Nervous System And Drugs

Question 1

Describe synaptic transmission

Answer 1

• a nerve impulse travels along axon of a neuron towards the synaptic terminals on the pre synaptic neuron
• neurotransmitters will then released from vesicles, travel to synapse
• neurotransmitter then binds to complementary receptors on post synaptic neuron
• post- SN be will depolarised once enough receptors have been stimulated=so message been passed on
• left over neurotransmitters will be taken back in re uptake pump to be destroyed by enzymes or store back in vesicles for later use

Question 2

2 ways of how drugs work on transmission process

Answer 2

• block re uptake pump
• mimic neurotransmitters

Question 3

What is the effect of blocking re uptake pump ?

Answer 3

neurotransmitters cannot be re uptake = cause a build up in synapse = post synaptic neuron fire more frequently so message pass more often = INCREASE activity

Question 4

What is the effect of drugs mimic neurotransmitters ?

Answer 4

• they will fit in receptors, leave less receptors site that can be excite by actual neurotransmitters
  = reduce amount of neurotransmitters produced = less firing of neurons = reduce activity

Question 5

How do people become addicted to recreational drug?

Answer 5

• R.D stimulates ‘reward pathway’ of your brain, causes dopamine level increase over optimum level
• this causes euphoric high which mean you feel happier than you normally feel
• the sudden increase of dopamine in the brain causes it to down regulates= so you brain naturally produce less dopamine
• when the drug wears off, your natural dopamine level is too low that is insufficient for regular function so experience dysphoria which results in extreme withdrawal symptoms e.g. shaking and dizziness
• this encourages you to take the drug again in higher dosage to reach to the euphoric state again = addiction

Question 6

How does alcohol work inside the body to change behaviour?

Answer 6

• increases serotonin= makes you feel happier
• increases release of GABA (responsible for generating nerve impulse ), GABA inhibits firing of neurons = causing sedative effect on brain function+ memory less efficient

Question 7

What does cocaine do to affect behaviour ?

Answer 7

• blocks re-uptake pump, leads to dopamine over stimulation = euphoria is reached so you feel happy
• this can reduce memory performance when drug wears off

Question 8

How does caffeine affect behaviour ?

Answer 8

• blocking adenosine receptors in brain = reduce adenosine activity = you don’t feel tired and more alertness and focus

Question 9

Features of using fMRI scan

Answer 9

• shows structure and activity of the brain
• strong magnetic field used= affect protons in hydrogen atoms in the brain = causing it to pull at the same direction as the magnetic field
• pictures are taken when protons go back to original position when M.F turns off
• more H atoms = paler, less H atoms = darker

Question 10

How can fMRI scan detects activity of the brain ?

Answer 10

• blood flow increases when brain is active = means more oxygen is carried through haemoglobin to different parts of the brain
• oxygenated blood = diamagnetic
• deoxygenated blood = paramagnetic

Question 11

Pros of fMRI scan

Answer 11

• high quality images of brain
• can compare structure of brains functioning normally or abnormally
• scientific
• non invasive

Question 12

Cons of fMRI scan

Answer 12

• expensive
• lacks ecological validity
• not suitable for all patients

Question 13

How is fMRI scan not suitable for all patients ?

Answer 13

• high powered magnetic Reid used
• e.g. people with cardiac pacemaker or a metal surgical implant = could cause disruption to the heart, physical harm or tear of metal object
• people with claustrophobia = can cause distress
  = t/f, not accessible for everyone = cause physical and psychological harm = may seen unethical

Question 14

How does PET scan work ?

Answer 14

• provides both structural + activity of brain
• an radioactive tracer bonds with glucose injected into patients blood
• different task done by patients = glucose is broken down when parts of brain uses in tasks = only radioactive material remains with gamma rays produced
• more gamma rays = more activity = red
• blue = less activity

Question 15

Pros of RET scan

Answer 15

• provides structure and activity of brain picture
• can compare structure of brain that function normally and abnormally
• practical application
• scientific

Question 16

Cons of PET scan

Answer 16

• low resolution image produced
• most expensive scanning techniques to use
• lacks ecological validity
• invasive method

Question 17

How is PET scans scientific ?

Answer 17

• high scientific equipment used that can easily be repeated
• scans are interpreted by specialist and peer review to be analysed in unbiased way
  = it can be objectively analysed to see impact of brain that results in certain behaviour = highly valid

Question 18

How does CAT scan work ?

Answer 18

• only shows structure of the brain
• x-rays used that passed around the head at different angles
• pictures shows how different area of brain react with the x ray = show how far x ray is blocked = if area is blocked = indicating abnormalities e.g. tumours

Question 19

Pros of CAT scan

Answer 19

• detailed image of structure of the brain
• non invasive

Question 20

Cons of CAT scan

Answer 20

• only produce structure image of the brain
• exposure of radiation