Brain and learning (8.8-8.15)

Question 1

Cerebral hemispheres

Answer 1

There is the left and right, made from the cortex

Each contain 4 lobes: Frontal, parietal, occipital and temporal

Question 2

Functions of cerebral hemispheres

Answer 2

Thinking, learning, speech, emotions, memory and ability to see

Question 3

White matter

Answer 3

Myelinated axons below the grey matter

Question 4

Corpus Cellosum

Answer 4

Axons which connect the two hemispheres together

Question 5

Frontal lobe

Answer 5

Located at front of the brain

Associated with decision making, planning and consciousness of emotions

Question 6

Parietal lobe

Answer 6

Behind the frontal lobe

Orientation, movement, sensation and memory

Question 7

Occipital lobe

Answer 7

At the back of the brain

Known as visual cortex, so processes information form the eyes

Question 8

Cerebellum

Answer 8

Bottom of brain

Balance

Question 9

Temporal lobe

Answer 9

In the middle

Processes auditory information

Question 10

Hypothalamus

Answer 10

Thermoregulatory centre and initiates corrective action to restore body temp to optimum level
Also acts as an endocrine gland and connects to the pituitary gland to secrete ADH

Question 11

Hippocampus

Answer 11

Long term memory

Question 12

Medulla oblongata

Answer 12

Regulates autonomic processes like heart rate and breathing

Question 13

Basal ganglia

Answer 13

Initiates stored programmes for movement

Question 14

Reasons why animals (mice) are used for investigating brain function

Answer 14

Similar brain structure to humans and can be easily bred and kept in a lab
The utilitarian approach is that the benefits outweigh the harms

Question 15

Criticisms of animal testing on brain function

Answer 15

Animals can’t give consent, and the process can be harmful

Animal may not behave like a human would

Question 16

CT scans

Answer 16

Narrow x rays produce low resolution 2D image
Less expensive and can identity location of tumours
But low clarity image so can’t look at functions of brain

Question 17

MRI scan

Answer 17

Magnetic field and radio waves cause hydrogen nuclei to emit absorbed energy
Gives high resolution images but is very expensive

Question 18

fMRI scan

Answer 18

Radio waves are reflected by oxyhemoglobin
Identifies brain activity in real time, with white areas containing oxygen ‘lighting up’
Able to delete tumours, as they also appear white

Question 19

PET scans

Answer 19

Radiotracers are used which releases gamma rays
Increased brain function, increase in blood flow, increases energy used, which increases radio tracers
They are 3D and very detailed, but expensive and only used 1-2 times a year for safety reasons

Question 20

PET scans used for Alzheimer’s

Answer 20

Use an amyloid tracer to monitor the position of plaque formations and monitor glucose metabolism in brain. Alzheimer’s causes decline in cerebral glucose metabolism

Question 21

Critical period

Answer 21

The period of time during early development which appropriate and specific stimulus is required for normal development

Question 22

How does the critical period affect the visual cortex

Answer 22

There is lots of overlap between synapses of the visual cortex at birth
Once the baby is exposed to light stimuli, some axons are stimulated and relate neurotransmitters and become stronger, whereas, other don’t and become narrower and die off

Question 23

Habituation

Answer 23

A form of learning whereby there is a change in response to a repeated, harmless stimuli

Question 24

How does habituation occur

Answer 24

• Repeated stimulation leads to high frequency of action potentials down motor neurones
• Ca2+ channels of presynaptic membrane become less responsive to the voltage changes of action potentials
• Fewer vesicles fuse with synaptic membrane, so less neurotransmitters are released across synapse
• Less neurotransmitters binding to receptors on post synaptic membrane
• Less depolarisation of post synaptic neurone so no action potential is triggered in motor neurone
• So no response occurs

Question 25

Dopamine

Answer 25

Neurotransmitter active in neurones of frontal cortex, brain stem and spinal cord
Associated with movement and emotional responses

Question 26

Parkinson’s disease

Answer 26

Death of dopamine secreting neurones in basal ganglia leads to low dopamine levels in brain and motor cortex
Leads to muscle tremors, slow movement and poor balance, accompanied with depression

Question 27

Treatments for Parkinson’s

Answer 27

L-Dopa increases levels of dopamine
MAD inhibitors slow loss of dopamine from brain
Dopamine Antagonists activate dopamine receptors on post synaptic membrane

Question 28

Serotonin

Answer 28

Neurotransmitter secrete by neurones in brain stem whose axons extend to context, cerebellum and spinal cord. It is associated with determining a person’s mood

Question 29

MDMA

Answer 29

Derivative of amphetamines found in ecstasy
It blocks presynaptic transporter proteins, preventing reuptake of serotonin
Leads to high levels of serotonin and more action potentials down these pathways

Question 30

Side effects of MDMA

Answer 30

Increased use leads to depletion of serotonin, leading to depression

Question 31

How does the medulla oblongata control breathing rate

Answer 31

• Inspiratory centre in medulla oblongata sends nerve impulses to intercostal muscles and diaphragm to contract
• Increases volume in lungs, lowers pressure, so air enters
• Lungs inflate, so stretch receptors are stimulated in lungs which send impulses back to medulla oblongata to inhibit the inspiratory centre
• Expiratory centre is no longer inhibited and sends impulses to diaphragm and intercostal muscles to relax