discuss the methods open to studying the biological bases of behaviour
...lems involving these techniques are that all the regions of the brain are interconnected. Damaging one region may coincidentally damage or affect other regions. Another disadvantage is that this method has several ethical considerations to make regarding welfare of the animals involved. Recent developments in computerised technologies have allowed researchers to examine the human brain whilst alive, which previously has been restricted. Non-invasive techniques enable researchers to view neural structures and functions in the living brain of both humans and animals. It involves regional cerebral blood flow. When an area of the brain becomes more active its blood supply, use of glucose and synthesis of proteins increases. The most commonly used technique is the computerised axial tomography - CAT scan. Radioactive substances used by Andreasen (1988), conveys which area of the brain is most active during which behaviours. A computer plots a two dimensional image of horizontal sections through the brain as X-ray emitters in the circular arrangement pass through the brain. The technique provides the opportunity to successfully study cerebral cortical alterations in disorders such as Alzheimer’s disease, Schizophrenia and dyslexia (Rosenzweig, Leiman & Breedlove, 1999). The advantage of a non-invasive technique is that it doesn’t damage the brain so can be used on living humans. One of the key disadvantages though is that the CAT scan only provides horizontal pictures portraying the structures of the brain. A different type of scanning technique known as the position emission tomography - PET scan provides information on how the brain functions in particular circumstances, which can prove to be more use full. It involves either inhaling oxygen or injecting radioactive substances like glucose or carbon that act as a tracer. The radioactive substance is then taken up by a particular region of the brain, and viewed under ultraviolet light. The location of the tracer is then examined (Smith & Fetz, 1987). The principle advantage is that it informs researchers how the brain functions in particular circumstances. However it is mildly invasive as it can cause slight damage to living cells in the brain, so is used hesitantly. Recording the electrical activity in the brain allows researchers to determine whether a specific region in the brain is related to certain behaviours. There are two types of measures: 1. Microelectrodes 2. Macro electrodes Microelectrodes can record the electrical activity in a single neuron, known as a ‘single unit recording’ (Carlson, 1994). Microelectrodes are implanted chronically into the brain of an animal, and the electrical activity is monitored as the animal responds to particular environmental stimuli. This method is extremely precise however the actual studies can be very time consuming. One can also criticise that it is too focused on one aspect of neural transmission and neglects neural interactions. On the other hand macro electrode allows researchers to record the activity of many neurons. The electroencephalogram gram (EEG) involves placing active electrodes are placed at the site of neural activity. An indifferent electrode is placed at some distance from this site. It measures the potential difference between the active and indifferent electrodes. Caplan (1985) conveyed that changes in electrical activity are obvious in behavioural states such as arousal, wakefulness and sleep. Abnormal electrical activity signals disease states such as epilepsy and coma. Not only are macro electrodes a non-invasive technique but allows researchers to differentiate between neurological conditions and behavioural states. However again the procedure is time consuming and the results can be crude as the averaging activity in many neurons cannot establish the precise activity in a particular region. Chemical and genetic approaches used to study the brain can tell researchers the location of specific neurons that produce and secrete particular neurotransmitters. Methods involve introducing specific drugs, enzymes or antibody’s (that will interact with a specific neurotransmitter) and observing the effects. Researchers can also use biochemical methods to direct a mutation of a particular gene (Joyner & Guillemut, 1994). The gene-knockout approach can for example destroy or alter widespread systems of cells providing information that other methods cannot. Micro dialysis is a method Westerink in 1995 used allows researchers to measure the amounts of neurotransmitters that are released during various behaviours. In schizophrenia, amphetamines increase the production of dopamine transmissions whic...