Lesson 8 The Biological Approach The Infouence Of Biological Structures And Neurochemistru On Behaviour

Question 1

Biological structures

Answer 1

Neurons and the nervous system
Brain

Question 2

What are neurons and the nervous system

Answer 2

• The CNS (central nervous system) consists of the brain and the spinal cord, and controls breathing, and heart rate
• The PNS (peripheral nervous system) sends and receives messages from the CNS to other parts of the body e.g. limbs using individual cells called neurons
• Neurons transmit nerve impulses in the form of electrical signals

Question 3

Brain

Answer 3

• The brain is made up of the left and right hemisphere, and in total has 4 lobes (see image). Using your iPad name the 4 different lobes of the brain and find out the function of the lobe

Question 4

What are the four lobes in the brain

Answer 4

Parietal lobe, occipital lobe, frontal lobe and temporal lobe

Question 5

Parietal lobe function

Answer 5

Sensation, dealing and reacting to the environment

Question 6

Frontal lobe function

Answer 6

Executive function, emotional contract

Question 7

Temporal lobe function

Answer 7

Language, hearing, memory

Question 8

Occipital lobe function

Answer 8

Vision

Question 9

Advantages of biological structures

Answer 9

1) The biological model has its strengths in that the study of the brain relies on the use of scans, such as PET (Positron Emission Tomography) and MRI (Magnetic Resonance Imaging) and post mortem studies which adds to scientific evidence than can help support the biological approach. It can be viewed as one of the most scientific models/approaches (+)

5) An advantage of looking at brain structures is they can be scientifically and objectively investigated in order to test how they might affect behaviour. For instance the brain can be investigated using FMRI and PET scanning which gives psychologists access to investigating and understanding how the brain functions (+)

Question 10

Disadvantages of biological structures

Answer 10

2) The biological model can be criticised because it is more applicable at explaining the causes of some behaviours, but not others. For instance infection or neuroanatomy of the brain can cause schizophrenia, but there are some behaviours that cannot be well explained by these ideas. For instance the development of phobias is usually learnt (-)

3) Cause and effect is a disadvantage when looking at biological structures and their effect on behaviour. For instance can psychologists be sure that a brain malfunction is causing a behaviour to occur, e.g. a smaller hypothalamus causing schizophrenia? (-)

4) A problem of studying the brain is that psychologists still do not know 100% about the brain and its functions. Therefore there could be problems of trying to identify which part of the brain is responsible for certain behaviours and more investigation might be needed. (-)

Question 11

Brain structure: Neural Correlates: AO1

Answer 11

• Schizophrenia might develop due to structural and functional brain abnormalities.
• Post mortems were used to investigate the structure of the brain in patients who had schizophrenia, but we now use fMRI (Functional Magnetic Resonance Imaging)

Question 12

Brain structure: Neural correlates: A study by Swayze

Answer 12

• Swayze reviewed 50 studies of schizophrenic patients and examined their brain imaging using MRI (Magnetic Resonance Imaging).
• From these brain images, the structure of the brain could be examined and it was found that schizophrenic patients’ have structural abnormalities in their brain including:
• A decrease in brain weight
• Enlarged ventricles (that are filled with water)
• A smaller hypothalamus
• Less grey matter (this is where the intelligence is held and it seems to have deteriorated)
• Structural abnormalities in the pre frontal cortex (where the personality is held)

Question 13

Advantages of the study by Swayze

Answer 13

There is a strong amount of supporting psychological evidence to state that schizophrenia is caused by neural correlates changing in the brain that occur during pre-natal development in the womb. However, this does not explain why schizophrenia occurs in early adulthood (and not straight away during infancy). (+)/ (-)

Question 14

Disadvantages of the study by Swayze

Answer 14

Andreason (1982) has criticised the neural correlates explanation for schizophrenia. He found that the extent to which the ventricles in the brain are enlarged in schizophrenic patients is not significant; and therefore there is actually very little difference between the neural correlates of schizophrenic patients’ and normal people. (-)

2) Cause and effect needs to be established. Is it the fact that abnormal neural correlates actually causes schizophrenia to occur, or does schizophrenia occur first (due to other factors) and then cause the brain structure/neural correlates to alter? (-)

3) There is a strong amount of supporting psychological evidence to state that schizophrenia is caused by neural correlates changing in the brain that occur during pre-natal development in the womb. However, this does not explain why schizophrenia occurs in early adulthood (and not straight away during infancy). (+)/ (-)

4) Davison and Neale (2001) have found contradictory evidence to suggest that enlarged brain ventricles are not only found in schizophrenia patients, but that sufferers of mania also have enlarged ventricles. Therefore enlarged ventricles alone cannot cause schizophrenia, but it could be a vulnerability factor that increases the risk of getting the illness. (-)

Question 15

Neurochemistry/neurotransmitters and it’s effect on behaviour (AO1)

Answer 15

• This looks at the biochemistry of the central nervous system which involves hormones and neurotransmitters
• Hormones such as testosterone travel in the blood stream
• Neurotransmitters defined as, “Brain chemicals that communicate information throughout our brain and body. They relay signals between nerve cells, called neurons”
• In the brain the transmission of chemicals – (neurotransmitters) occurs via cerebral fluid, for instance high levels of dopamine cause schizophrenia

The endocrine system is responsible for producing hormones in the body, for instance high levels of testosterone might increase aggression levels.
• The endocrine system consists of ductless glands that release hormones into the body which will affect behaviour

Question 16

Advantages of Neurochemistry

Answer 16

2) Neurotransmitters can be measured objectively and scientifically which is a strength. For instance dopamine can be measured by inserting a needle in the spine and extracting spinal plasma fluid. This means we can obtain objective and scientific measurements (+)

3) A strength of neurotransmitters is that if we know that a lack/excess of a particular neurotransmitter has an effect on behaviour e.g. low levels of serotonin cause depression, then we can look for relevant treatments that can help solve the issue. For instance giving depressed people SSRI drugs that increase serotonin (+)

Question 17

Disadvantages of Neurochemistry

Answer 17

1) A negative point of neurochemistry is that cause and effect needs to be established. Can we be sure that high/low levels of neurotransmitters actually cause a change in behaviour, e.g. low levels of serotonin cause depression? (-)

4) Neurotransmitters can be viewed as reductionist which can be a disadvantage. To say that complex human behaviour can be affected by neurotransmitters alone is too simplistic and inaccurate, for instance is depression really just caused by low serotonin levels? (-)

5) The idea that neurotransmitters can have an effect on behaviour can be criticised by the cognitive approach. The cognitive approach would state that behaviour is caused by thought patterns and thinking rather than neurochemistry or chemicals, for instance depression could be caused by negative thinking according to the cognitive approach rather than by low levels of serotonin (biological approach) (-)

Question 18

Dopamine Hypothesis by David and Neale (AO1) A study into Neurochemistry and schizophrenia

Answer 18

• Schizophrenic patients’ tend to have high levels of the neurotransmitter dopamine in their brain
• When drugs such as phenothiazines are given to patients’ that block dopamine in the brain; the positive symptoms of schizophrenia seem to reduce (hallucinations and delusions)
• A drug called L-Dopa increases dopamine levels in the brain.
• This drug can induce symptoms of schizophrenia, and it has been tested on healthy non psychotic people.
• Drugs such as LSD and amphetamines (dopamine agonist) also increase dopamine levels in the brain and can induce schizophrenic symptoms.
• Dopamine metabolism in schizophrenic patients’ seems to be abnormal,

Question 19

Advantages of the Dopamine Hypothesis

Answer 19

There is a great deal of research to support the hypothesis that schizophrenic patients have a high level of dopamine in their brain. For instance research by Davidson found that when schizophrenic patients were given the drug L-Dopa their schizophrenic symptoms got worse and intensified. (+)

There is a great deal of scientific evidence and support for the dopamine hypothesis as a cause of schizophrenia. Most of the research has used evidence that have come from brain scans (PET and fMRI) which is highly valid and reliable information. This gives scientific and objective data (+)

Question 20

Disadvantages of Dopamine

Answer 20

Cause and effect is not clear. Could it be that an increase in dopamine causes schizophrenia to develop; or could it be that the illness develops first (due to another cause) and then this causes dopamine levels to increase? (-)

3) Dopamine is a neurotransmitter that is not only associated with the illness of schizophrenia. Dopamine has also been associated with mania (bipolar depression), and this illness is not alleviated by phenothiazine drugs. Therefore is seems that dopamine has a complex role in the brain and might be associated with many psychological illnesses and not schizophrenia alone. (-)

4) The dopamine hypothesis could be viewed as being reductionist. It looks at the complicated phenomenon of the causes of schizophrenia and reduces it down to the component of dopamine alone. (-)