The Biological Approach

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  • Created by: lauren
  • Created on: 06-05-14 09:17


  • Behaviour can be explained in terms of different areas of the brain;
    • different areas of the brain perform specialised functions, if those areas are damaged from a stroke etc - the person loses the particular function. the ceberal cortex covers the surface of the brain and is responsible for higher cognitive functions, frontal lobe is responsible for fine motor movement and thinking, occiptal lobe is assosciated with vision.
  • Behaviour can be explained in terms of neurotransmitters;
    • neurons are electrically excitable cells that form the basis of the nervous system - responsible for sending messages around the body. junction between neurons is called a synapse - which messages are transmitted across (neurotransmitters) the neurotransmitters are released from presynaptic vesicles in one neuron and will either stimulate of inhibit receptors in the other neuron
  • Behaviour can be explained in terms of horemones;
    • horemones are biochemical substances that are produced in one part of the body and circulate in the blood having an effect on target organs. produced in large quantities but disappear quickly, they have slow but powerful effects. male: testosterone female; oestrogen. horemones like adrenaline are also neurotransmitters.
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The biological approach aims to explain all behaviour and experience in terms of physical bodily processes, when you feel stressed this usually involves your heart pounding, plams sweaty and so on - these are physical symptons cause by the the nervous system.

the nervous system is divided into the central nervous system (CNS) and the automatic nervous system (ANS) and this is further subdivided into sympathetic and parasympathetic branches. the CNS comprises the brain and spinal cord containing 12 billion nerve cells (neurons)

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Selye concluded that when animals are exposed to unpleasent stimuli, they display a universal response to all stressors - general adaptation syndrome - G: same response to all agents, A: it is adaptive - healthiest way to cope with stress S: several symptons in stress response

  • Alarm Reaction; threat of stressor is recognised, the hypothalamus in the brain triggers the production of adrenaline from the adrenal glands. adrenaline causes 'adrenaline rush' - increased heart rate, sweaty palms, fast breathing. leads to fight of flight..
  • Resistance; if stress continues you find means of coping, body is adapting to the demands of the environment, but  at the same time resources are gradually being depleted - body seems to be coping but things are deteriorating.
  • Exhaustion; eventually bodys system can no longer maintain normal functioning - initial symptons reappear, adrenal glands may be damaged and immune system cant cope because production of necessary proteins (cortisol) has been slowed in favour of other needs, result may be sen in stress related illnesses such as ulcers, depression, cardiovascular problems and other mental and physical illnesses.
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    • worked in hospital and noticed all patients shared set of symptoms, later when conducting research on rats (1936) noticed this generalised response. no matter what substance the rats were injected with - all had similar response. the aim was to test the hypothesis
    • rats were exsposed to various noxious agents: cold, surgery injury, spinal shock, excesive muscilar exercise, overdoes of drugs
    • typical syndrome was observed, symptoms were independant of the nature of damaging agent or type of drug - syndrome develops in three stages;
      • all stimuli prodcued same psychological triad: enlargement of adrenal glands, ulcers in digestive system, shrinkage of immune system
      • if treatment was continued, appearance and function of organs returned to normal
      • with continued treatment, after 1-3 months animals lost resistance and displayed psychological triad symptoms.
  • results support doctrine of non specifity' response similar to general defence reactions to ill
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BIOLOGICAL THERAPY - psychosurgery

    •  trepanning - hole cut into skull of living person to releave evil spirits.
    •  In 1940's a new form by Egas Moniz who heard about monkeys with aggressive tendancies were subdues after their frontal lobes were removed. he developed a similar operation for humans,
    • this method was popularised by Walter Freeman who used 'ice pick technique' hammering an ice pick into patients tear duct and wiggling it around to sever connections between the prefrontal cortex and brain.
    • psychosurgery is a surgical procedure that is performed on the brain with the aim of treating mentally disordered behaviour, it involves destroying sections of the brain, or severing fibres  so the target areas of the brain are seperating and functionally removed.
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    • involves selective destruction of nerve fibres, performed on frontal lobe, an area that is involved in impuse control and mood regulation.
    • it is to alleviate some of the severe symptoms of mental illness
    • initally it was performed on patients with affective disorders like depression and OCD and less successfully Schizophrenia
    • Moniz developed a surgical procedure called a prefrontal leucotomy in 1930s - this involved drilling a hole in either side of the head and inserting an insturment that resembles an ice pick to destroy nerve fibres underneath.
    • moniz later refinied this technique by designing a 'leucotome' an instrument with a wire loop that could cut through white matter of the brain and sever nerve fibres it was hoped that cutting into nerve pathways that carried thoughts from one part of the brain to the other, would relieve patients of their distressing thoughts and behaviour
    • the early practice of psychosurgery was inapropriate and ineffective - had a fatality rate of 6% and a range of severe physical side effects such as brain seizures and lack of emotional responsivenes
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    • more developed and precise way to surgically treat mental disorders such as OCD, bipolar, depression and eating disorders
    • instead of removing large sections from frontal lobe, neurosurgens use MRI scans to locate exact points in the brain to sever connections precisly using anaesthetic
    • in OCD for example, a circuit linking the orbital frontal lobe to deeper structures in the brain such as the thalamus, appears to be more active than normal. the bilateral cingulotomy is surgically designed too interrupt this circuit- surgeons either burn away tissue of use a gamma knife to focus beams of radiation onto target
    • in a capsulotomy, surgeons insert probes through top of skull and down into capsule a region of the brain near the hypothalamus that is part of the circuit connecting this area to the cortex - they heat the tip of the probes to burn away tissue
    • Cosgrove and Rauch (2001) reported cingulotomy was effective in 56% of OCD patients and a capsulotomy in 67%. in major effective disorder,cingulotomy was 65% and capsulotmy 55%
    • but authors clamied only 25 patients are treated this way a year  - small study
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    • a possible alternative to psychosurgery is DPS where surgeons thread wires through the skull and no tissue is destroyed
    • the wires remain embedded in the brain and theyre connected to a battery pack implanted in the chest
    • batteries produce an adjustable high frequency current that interrupts the brain circuitry involved in, gor example OCD
    • if it doesnt work it can be turned off
    • Mayberg et al (2005) found that 4/6 patients with severe depression experienced a striking remission after treatment involving stimulation of small areas in the frontal cortex
    • similar techniques include transcranial magnetic stimulation and vagus nerve stimulation
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    • assumptions-behaviour explained by nerotransmitters and horemones, this means biological explanations have clear variables that can be measured, tracked and examined - ebales psychologists to conduct scientific research. psychosurgery and Selye are examples that fufill the scientific aims - well controlled  - support biological explanations
    • we know what predetermines behaviour-more likely to be able to treat people with abnormal behaviour, psychologists want to understand neurotransmitters so they can predict the effects of neurotransmitters on ab/normal behaviour. provides explanations about the causes of behaviour so we can understant to improve peoples lives
    • biological approach las led to many successful applications - Selyes research had a major impact on our understanding of the link between stress and illness. - led to more research findings have been applied to hospitals and is used to treat people
    • psychosurgery  - effectiveness of capsulotomy in the treatment of OCD - 67% effective
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    • reduce complex behaviours to a set of simple explanations - reducing stress to the action of horemone adrenaline - we may lose a real understanding of the thing we are investigating. Laing (1965) claimed such an approach ignores the experience of distress that goes along with any mental illness and therefore at best an incomplete explanation - a simplified explanation may prevent us reaching a true understanding of the target behaviour
    • mental illness has multiple causes, ignores life experiences and emotions. for example Schizophrenia is explained in abnormal levels of neurotransmitters rather than how patients feel about their illness
    • nomothetic- generalises people and tends to ignore individual differences, - some people have higher adrenaline than others=more stressed
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  • BRAIN SCANNING: enables psychologists to measure brain activity-
    • CAT scans take a series of x rays showing brain structure
    • MRI scans detect brain structure using magnetic detectors- provides detail with no radiation
    • fMRI provides a picture of the brain in action
    • PET scans detect chemical and structural information and show the brain in action but are very expensive and expose patients to radiation
  • TWIN STUDIES: enables psychologists to estimate the relative contribution of genetic (nature) and environmental (nurture) factors. high concordance rates for MZ twins demonstate the importance of nature, especially when compared with DZ twins and also twins reared apart
    • strengths: useful information tells us about nature and nurture
    • weaknesses: environments the same, twins reared apart share similar environments
    • Bouchard and McGue studied inheritance of IQ - sompared twins IQ  - (the degree which 2 people are similar is expressed as a concordance rate) so if two have the same IQ they have 100% concordance rate -looked at monozygotic (MZ) twins - share 100% of genes and are therefore identical - a review of more than 30 studies found a mean concordance rate of 86% - suggests a large part of intelligence appears to be inherited
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