Function and Brain Structure

Question 0

What is fMRI? How and what is it used for?

Answer 0

Modified version of (functional) MRI that can allow you to see brain in action this is because more oxygenated blood flows to active areas of the brain (to supply neurones with O2 and glucose).
Active areas can be identified.

Question 1

What does MRI stand for?

What is it used for?

Answer 1

MAGNETIC RESONANCE IMAGING.
Scans use MAGNETIC field and RADIO waves to make images of soft tissue like the brain. Can be used to diagnose tumours, strokes, brain injuries and infections. Can track degenerative diseases by comparing scans over time period.

Question 2

What is the benefit of using fMRI in medical diagnosis?

Answer 2

• Show damaged or diseased areas of brain and allow study of abnormal brain activity.
• E.g. can scan seizure before and during seizure to see which area not working properly and find app. treatment.

Question 3

What is ‘CT/CAT’? How does it work?

Answer 3

COMPUTERISED AXIAL TOMOGRAPHY
• Uses 1000’s narrow beam x-rays rotated around patient.
• Only captures at 1 moment in time and is used to look at structures and damage rather than functions.
• Poor pic. quality & x-rays ionizing.

Question 4

What are the medical uses of CT scans?

Answer 4

DIAGNOSTICS: shows damaged/diseased areas of brain.
• Blood diff. density from brain so shows up LIGHTER on CT.
• Scan will show extent of bleeding & location.
• Can work out which blood vessel damaged and what functions could be affected.

Question 5

What are the medical uses of MRI?

Answer 5

• Tumour cells respond diff. to magnetic field than healthy cells and show up as lighter colour.
• Scan will show exact size and location of tumour. Used to decide most effective treatment.
• Can see what brain funct. may be affected by tumour.

Question 6

What is Parkinson’s disease and what is it caused by?

Answer 6

Brain disorder that affects motor skills. Neurones that control movement destroyed and are usually produce by dopamine so losing them causes reduced dopamine levels.

Question 7

How does L-Dopa work?

Answer 7

Structure v. similar to dopamine. It is absorbed into brain and is converted into dopamine by enzyme dopa-decarboxylase. This incr. dopamine levels in brain. Higher level of dopamine means more nerve impulses transmitted across synapse to parts of brain that control movement so suffer has better move. control.

Question 8

How does MDMA (ecstasy) work?

Answer 8

Increases serotonin in the brain. It inhibits reuptake of serotonin neurotransmitters into presynaptic neurones. This means nerve impulses are constantly triggered in postsynaptic neurones.

Question 9

What is depression believed to be caused by?

Answer 9

Low levels of serotonin which is a neurotransmitter linked to reward and pleasure.

Question 10

DA fuq does dis PROZAC shit do? tELL ME!

Answer 10

Prozac is a SELECTIVE SEROTONIN UPTAKE INHIBITOR (SSRI) that blocks the process which removes serotonin from the synapse.

Question 11

What do dopamine agonists do?

Answer 11

They mimic dopamine due to similar structure and bind to dopamine receptors which trigger action potentials.

Question 12

What do inhibitory drugs do?

Answer 12

They block receptors on the post synaptic membranes and prevent neurotransmitters from binding.

Question 13

What is learning?

Answer 13

Process that results in a changed behaviour (or knowledge) as a result of experience. For learning to be effective, you must remember what you have learnt.

Question 14

How are memories (conscious and sub-concious) formed?

Answer 14

By changing or making new synapses in the nervous system.

Question 15

What is habituation?

Answer 15

A very simple type of learning that involves the loss of response to a repeated stimulus which fails to provide any form of reinforcement. It allows animals to ignore unimportant stimuli so that they can concentrate on more rewarding or threatening stimuli.

Question 16

How is habituation achieved?

Answer 16

With repeated stim., Ca2+ channels become less responsive so less Ca2+ crosses presynaptic membrane. Less neurotransmitter released. There is less depolarisation of the post synaptic membrane so no action potential is triggered in the motor neurone.

Question 17

What is nature and what is nurture. Provide examples for both.

Answer 17

• Nature: characteristics caused by genes and little by environment e.g. blood type.
• Nurture: characteristics mainly influenced by environment e.g. length of hair.

Question 18

Why is it hard to investigate effects of nature and nurture?

Answer 18

• Gene-envirn. interaction
• Many genetic and environ. factors to investigate.
• Can’t remove nature or nurture to test for influence of each.

Question 19

What evidence is there from newborn babies that show support for nature?

Answer 19

Newborn babies not really affected by environment and have some innate capabilities which suggests that genes help to form the brain and some behaviours before baby is born. e.g. cry, feed.
• Can’t speak - suggests role of nurture.

Question 20

How can twin studies show the role of nature and nurture in brain development?

Answer 20

M/Z genetically identical and D/Z share same genes as siblings. Can help est. contribution of genes and environment. Higher degree of similarity = genetic, lower = nurture. e.g. twins raised apart - greater difference suggests environmental role.