Brain and learning (8.8–8.15)

Question 1

What is the function of the cerebrum?

Answer 1

Involved in vision, learning, thinking, emotions and movement.

Back is involved in vision and the front is involved in thinking.

Question 2

What is the location of the cerebrum?

Answer 2

The outside top layer of your brain.

Question 3

What is the function of the hypothalamus?

Answer 3

Maintains body temperature and produces hormones that control the pituitary gland.

Question 4

Where is the hypothalamus found?

Answer 4

Just beneath the middle part of the brain.

Question 5

What is the function of the medulla oblongata?

Answer 5

Controls breathing rate and heart rate.

Question 6

What is the location of the medulla oblongata?

Answer 6

Base of the brain at the top of the spinal cord.

Question 7

What is the function of the cerebellum?

Answer 7

Coordinating movement and balance

Question 8

Where is the cerebellum?

Answer 8

Underneath the cerebrum (srivelled thing)

Question 9

How do CT scanners work?

Answer 9

They use radiation to produce cross sectional images of the brain. Dense structures absorb more radiation so show up lighter on the screen.

Question 10

How might a CT scan be used to investigate brain structure and function?

Answer 10

Shows the diseased or damaged brain structure and if patient has lost some function the function of that part of the brain can be worked out.

Question 11

How can CT scans be used in medical diagnosis?

Answer 11

Show damaged or diseased areas of the brain eg the location and extent of a brain bleed. Can then work out which blood vessels have been damaged.

Question 12

How do MRI scans work?

Answer 12

Use strong magnetic field and radio waves to produce cross sectional images of the brain.

Question 13

How can MRI scanners be used in investigating brain structure and function?

Answer 13

Allow see difference between normal and abnormal brain structures in better resolution. However can only be worked out by looking at damaged areas.

Question 14

How can MRI help with medical diagnosis?

Answer 14

Show damaged mass eg tumour. Tumour cells show up differently as they respond differently to magnetic field.

Show the exact size and location.

Question 15

What is an fMRI?

Answer 15

Show changes in brain activity as they happen. More oxygenated blood flows to areas as it happens and oxygenated blood responds differently to deoxygenated blood.

Question 16

How can an fMRI be used to investigate brain structure and function?

Answer 16

Asking to carry out a task then seeing which part of the brain becomes active.

Question 17

How can fMRI be used in medical diagnosis?

Answer 17

Shows diseased or damaged areas and allow study abnormal activity. eg brain before during a seizure allowing to pinpoint exactly what part of the brain isn’t working properly.

Question 18

How does a PET scan work?

Answer 18

Radioactive tracer is injected eg radioactively labelled glucose.

Question 19

How are PET scans used to investigate brain structure and function?

Answer 19

Very detailed and can be used to investigate both the structure and function in real time.

Question 20

How can PET scans help with medical diagnosis?

Answer 20

Show areas that are unusually inactive or active eg Alzheimer’s metabolism in certain areas is reduced.

Question 21

What is habituation?

Answer 21

Animals increase survival by responding to a stimulus.

If the stimulus is unimportant and repeated over a long time the animal learns to ignore it.

Habituation means animals don’t waste energy on unimportant stimuli.

Question 22

How does habituation result in fewer electrical impulses being sent to the effectors

Answer 22

1. Repeated exposure to a stimulus decreases the amount of calcium ions that enter the presynaptic neurone.
   
   1. This decrease in the Ca+ means that less neurotransmitter is released from vesicles into the synaptic cleft, so fewer bind to the receptors in the post synaptic membrane.
   2. Fewer sodium ion channels on the postsynaptic membrane open so there is a reduced chance of the threshold for an action potential being reached.
   3. So fewer signals are sent to the effector.

Question 23

Where is the visual cortex?

Answer 23

Back of the cerebral cortex.

Question 24

What are neurones in the visual cortex grouped into?

Answer 24

Ocular dominance columns.

Question 25

How are ocular dominance columns arranged in the visual cortex?

Answer 25

Same size and arranged in an alternating pattern across the visual cortex.

Question 26

How did Hubel and Wiesel investigate how the visual cortex developed?

Answer 26

1. Stitched one of the eyes of the kitten shut.
2. Left for several months.
3. Eye that had been stitched up was blind.
4. Ocular dominance was much small in the stitched up eye and found ocular dominance for open eye were a lot bigger than normal.

Adult cat

1. stitched shut for several months and found fully recovered their vision adn their ocular dominance remained the same.

Question 27

How did Hubel and Wiesel provide evidence for critical period in humans and what are the implications of that?

Answer 27

There’s an early period in life when its critical that a person is exposed to visual stimuli for the visual cortex to develop properly. Called the critical period.

This means if a baby is born with cataract its important to remove it within the first few months otherwise vision will be damaged for life.

Question 28

Why will the visual cortex not develop properly if its not exposed to proper visual stimuli?

Answer 28

During critical period synapses receive visual stimulation and pass nerve impulses into the visual cortex.

Synapses that don’t receive visual stimulation and don’t pass on any nerve impulses to the visual cortex are removed.

This means that if the eyes are not stimulated with visual information the visual cortex will not develop properly as many of the synapses will be destroyed.

Question 29

Give 4 arguments for the use of animals in medical research

Answer 29

1. Similar to humans so research has lead to medical breakthroughs
2. Only done when necessary and scientists follow strict rules
3. Only way to currently study how a drug effects the whole body.
   
   1. Humans greater right to life due to more complex brains.

Question 30

Give 4 arguments against the use of animals in medical research?

Answer 30

1. Animals different from humans so may have different effects
2. May cause pain and distress
3. Alternatives such as computer models.
4. Animals have the right to not be experimented on.

Question 31

What is Parkinson’s disease?

Answer 31

Brain disorder that effects motor skills.

Question 32

How does Parkinson’s disease work?

Answer 32

Neurones in the parts of the brain that control movement are destroyed.

These normally produce the neurotransmitter dopamine, so losing them causes a lack of dopamine.

Less dopamine is released into the synaptic clefts, so less dopamine is available to bind to the receptors on the post synaptic membranes.

Fewer sodium ion channels on the post synaptic membrane open, so less likely to depolarise.

So fewer action potentials are produced leading to symptoms such as tremors and slow movement.

Question 33

What do scientists think causes depression?

Answer 33

Link between low serotonin and depression.

Serotonin transmits at parts of the brain that control mood.

Question 34

How does L-dopa treat the symptoms of Parkinson’s disease?

Answer 34

Structure is very similar to dopamine.

When given it is absorbed into the brain and converted into dopamine by the enzyme dopa-decarboxylase. Which increases the level of dopamine in the brain.

A higher level of dopamine means that more nerve impulses are transmitted across the synapse in parts of the brain that control movement.

Question 35

How does MDMA work?

Answer 35

Increases the level of serotonin in the brain.

1. MDMA increase the level of serotonin by inhibiting the reuptake of serotonin into presynaptic neurones where it blocks the reuptake proteins.
2. MDMA triggers the release of serotonin from the presynaptic neurones.

This means that serotonin levels stay high in the synapse and cause depolarisation.