- Created by: 11v
- Created on: 07-02-19 10:50
Communication within our nervous system. Each neurone communicates with other neurones by sending chemical messengers called neurotransmitters. A signal called an action potential sends an electrical signal down the neuron. The neurotransmitters are released from their vesicles into gap between another neuron, which is called the synapse. They cross from the pre-synaptic membrane, and be collected from receptor sites on the post-synaptic membrane. Neurones recycle any left-over neurotransmitters through a process called reuptake. For example, low levels of the neurotransmitter serotonin causes depression. Addiction reduces the number number of dopamine receptors, meaning addicts need more of the drug to get the same 'high'.
Localisation of brain function
- The brain has two hemispheres, the left and the right. A collection of nerves called the corpus collosum joins the two hemispheres.
- Each hemisphere is divided into 4 lobes, the frontal lobe, parietal, temporal and occipital. The outside is called the cortex. Different areas have different functions and can influence our behaviour. If they are changes or are unusual, it can adversely affect our behaviour.
- Frontal lobe- personality, emotions, judgement, speech intelligence.
- Temporal lobe- language, memory, hearing, organisation
- Parietal lobe- language, senses, perception
- Occipital lobe- interprets vision (depth, colour, light).
- For example, Charles Whitman, who became a mass murderer. On his autopsy, it was found he had a large tumour on his amygdala, which is associated with violence and aggression.
- Theory of evolution, natural selection. Human mind and behaviour adapted over millions of years to meet demandsof individual environments.
- Genetically determined behaviour that enhances survival and reproductionwill be passed onto to the next generation as these genes are most likely to survive. Some offspring enable them to cope better with the demands of the environment, so they are most likely to survive and pass on their genes.
- Evolutionary psychology is about identifying which behaviours and traits have evolved as a result of natural or sexual selection.
- EEA- Environment in which a species has adaptedto the selective pressures that existed at the time. 2 million years ago- forest to savannahs.
- Example- stress hormones- fight or flight.Problems in the modern world.
Formation of relationship- romantic
- Sexual selection- Traits that increase chances of mating success. Mate preferences. Characteristics we are attracted to to enable greatest reproductive success.
- Parental investment- Females have a high parental investment. Physical and biological resources. More likely to be choosier when choosing a mate- they will choose a mate who can provide resources such as food and protection. This will enhance the female's reproductive success. Greater chance of survival. Financial prospects and ambition.
- Reproductive value- Probability of reproducing in the future. Physical characteristics such as smooth skin and muscle tone. Mating with youthful women is more likely to reproduce. They like women to have good looks, they like chastity.
- Buss- 37 cross-cultural study. Investigation into mate preferences. evolution-based, innate means it was prevelant across all cultures.
Drug therapy- link to apprach
One biological psychology assumption is that our feelings and mood are determined through the process of neurotransmission, the method of communication in our nervous system. Biological psychologists believe that mental health problems are caused by an imbalance of neurotransmitters in the brain, which adversely affect mood and behaviour. The aim of drug therapy is to create a balance of neurotransmitters in the brain so that the symptoms of the mental health disorder are alleviated. For example, depression is caused by low levels of serotonin in the brain, and so drug therapy is used to create a balance using a SSRI. This would lead to an improved mood.
Main components of drug therapy
SSRI's- used to treat depression, which is thought to be caused by low levels of serotonin. This works by blocking the reuptake of serotonin in the presynaptic membrane.
Conventional antipsychotics- Schizophrenia is thought to be caused by an oversensitivity to dopamine. This blocks the action of dopamine by binding to but not stimulating dopamine receptors.
Atypical antipsychotics- Schizophrenia is thought to be caused by an oversensitivity to dopamine. Temporily occupying dopamine receptors then rapidly dissociate.
Benzodiazepines- used to treat stress and anxiety- fight and flight response. Slowing down the activity of the central nervous system by enhancing the activity of GABA, the body's natural form of anxiety relief.
Beta blockers- stress and anxiety- fight or flight- binding on adrenaline receptors on the heart, which lowers heart rate and calms the body down.
Effectiveness of drug therapy
Davies- relapse occured in 55% of the patients' whose drug was replaced by a placebo, but was significantly less in those who actually took the drug. Analysed the results of 29 studies. Effective for those who are recovering. Still 19% of people relapsed, not completely effective. Outdated, was done in 1980. 19% improved without taking the drug.
Kirsch- reviewed clinical trials of SSRI's and concluded that only in the cases of severe depression were there any significant advantages to using it. Only for the most depressed group was there any difference between the drug and placebo. Less effective for those with mild depression. However, self-report- what they say may not be accurate.
Cost effective- cheaper, although other therapies may more effective. CBT. Publication bias- "file draw phenonemon"- not publishing reports that showed it to be ineffective.
Hollon- treats the symptoms and not the cause- 31% CBT vs drug therapy 75% relapse.
Drug therapy- ethical considerations
Side effects- SSRI's can cause nausea, headaches and insomnia. Ferguson et al found that those treated with SSRI's were twice as likely to commit suicide. Coventional antipsychotics cause tardive dyskinesia. Benzodiazepins are highly addictive. Cost-benefit? creating more issues. Withdrawal- going back on the drug.
Valid consent- those prescribed with these drugs may be in a vulnerable state- may not be able to understand. Gets them in a place where they are less vulnerable.
Issue of over-prescribing- may not be treating underlying cause of the problem- not improving, can become relaint on the drug. Other therapies may be more beneficial in treating these conditions. Self-help techniques. They're seen as a 'quick fix'.
Evaluation of the approach
Point 1- determinist
Point 2- nomothetic
Point 3- nature
Point 4- scientific
Point 5- reductionist
Methodology of Raine et al
Matched pairs design
DV- brain activity shown in brain scan
Murderers- 41 participants, 39 men and 2 women. Mean age of 34.3 years. All given an NGRI (not guilty by reason of insanity). Head injury, drug use, disorders such as schizophrenia or personality disorder. Not taing regular psychoactive drugs.
Non-murderers- 41 participants, 39 men and 2 women. Mean age of 31.7 years. Matched for age and sex, matched in other areas e.g. 6 people in both groups had schizophrenia. Physical exam and psychiatric history noted.
Procedures of Raine et al
1) Ten minutes before FDG injection, they were given practice trials of Continuous Performance Task (CTP). Simple, tedious task.
2) Full run of task started 30 seconds before injection as to not interfere with PET scan process.
3) FDG (radioactive tracer, Flurodeoxyglucose) injected, task undertaken for 32 minutes.
4) Then the subject was transferred to a PET scan where the brain was scanned in 10mm slices. When a part of brain is active, it uses glucose, radioactive detectors in scan can see the areas that are active.
5) Compared on 14 brain areas. 6 cortical areas including the prefrontal cortex and 8 subcortical areas including amygdala and hippocampus.
6) Brain assessed using two methods using cortical peel and box technique.
Findings of Raine et al
- Reduced glucose metabolism in bilateral prefrontal cortex, the posterior parietal cortex (bilateral superior gyrus and left angular gyrus and corpus collosum.
- Abnormal asymmetries of activity (left hemisphere lower than right) in the amygdala, thalamus and medial temporal gyrus including the hippocampus.
- Reduced glucose metabolism in PREFRONTAL CORTEX, ANGULAR GYRUS and CORPUS COLLOSUM (low corpus collosum activity, negative emotion generated by right side not regulated by left side).
- Left hemisphere activity was lower than the right in the murderers: AMYGDALA, HIPPOCAMPUS and THALAMUS.
- No difference between the groups in CAUDATE, PUTAMEN, GLOBUS PALLIDUS, MIDBRAIN and CEREBELLUM.
Prefrontal cortex linked to impulsivity, loss of control and aggression.
Low activity in Angular Gyrus is associated with low IQ and learning deficits. May predispose.
Amygdala and hippocampus are part of the limbic system, associated with fear, memory and emotion.
Conclusions from Raine et al
- Biology isn't the only thing that can predispose violence; social, psychological, cultural and situational factors can also contribute to violence.
- Responsibility should not be taken from the criminals in response to research.
- Cause and effect could not be established in research nor could a general direction.
- Cannot be generalised to other types of offender who possess a NGRI.
- It cannot be established whether these differences are specific to to violent criminals, no non-violent criminal control group.
- Statistically different in selected brain areas compared to normal. One of many predispositions. More research needed to generalise, as well as replication.
Evaluation of Raine et al
- Population validity- A large group was involved. the Researchers pointed out that this was the largedt group to have ever been part of a PET scan study. However, the plan might lack generalisability, non-violent criminal control group? Criminals without NGRI?
- Internal validity- The researchers used a control group who were matched on variables such as ageand sex and tehy were controlled for effect of medication. The study was a quasi experiement, which gave information on a area that would otherwise be unable to study, however, can't controll all variables. All scans were done after the criminals completed act (C+E), and the change in brain could be due to other factors. Shows relationship but not cause and effect. Coldnn't randomly allocate, leaving study vulnerable to researcher bias.
SI and EI- Raine et al
- Ethical issues- PET scans are a relatively non-intrusive form of investigating the brain. However, the murderers had all been given NGRIs and may not have fully understood the implications of the study. Might not have felt they had a right to withdraw. Study may remove responsibility from murderers for committing the crime.
- Social implications- the scientific nature of the study increases confidence in the research, making it more credible. Treatment possibilities to alter brain structure. May indicate to some that they're 'born and not made', which could have consequences for society.