Different techniques and their contributions to our understanding of the human brain
There is a unified system between biology and psychology in that biological and psychological factors interact in important ways.
Technology has a crucial part in understanding the brain and it has helped researchers to relate brain activity to behaviour. Investigating brain activity with different methods and an understanding of how information is transmitted, decoded, sent to the brain and from the brain through cells gives a very good insight into occurring behaviour and mood.
The brain is an extremely complex system. Studies and methods that turn to biology and physiology for support to explain psychological states are useful in trying to understand the brain.
It is possible to record electrical activity and the frequency of it in a neuron when it is stimulated (e.g. needle pierces skin) and also in resting state ( Toates, 2001, cited in Phoenix 2002).
By looking at the activity of neurons in the brain it is also possible to explain a psychological phenomena, a certain behaviour or mental illnesses such as schizophrenia.
Studying the structure of the brain can give good insight into how something as complex as the brain works and underlies cognition, control of behaviour or consciousness.
Neurons combine to form neural systems. The brain itself is composed of about one hundred billion neuron cells and any activity of the brain depends on the communication within and between these cells.
Communication between cells is by chemical means (neurotransmitters) through synapses (junctions), and within a cell it is by electrical activity.
Because our environment effects our behaviour and in turn behaviour effects our environment, and also neural activity effects behaviour and behaviour effects neural activity ( Gottlieb, 1998, cited in Phoenix 2002 ) it is important to look at biology and physiology to find the links with psychological phenomena.
Amongst the different methods there are the so called invasive techniques, in that they invade the nervous system in some ways, and non-invasive techniques.
Invasive techniques include brain surgery and experimental lesions.
Surgery to correct epilepsy was pioneered by R. Sperry (1969). Here
behaviour of patients (e. g. performing memory tasks) is compared before and after surgery. The brain is divided into left and right hemispheres, and
the part that connects the two is called the corpus callosum.
Surgical cutting through the corpus callosum has been shown to cure epilepsy to a great degree but also to disrupt communication between the two hemispheres.
The electrical stimulation of different regions of the brain can result in different manipulations of behaviour in patients ( Penfield and Rasmussen, 1968 , cited in Phoenix 2002 ). For example electrical stimulation of the temporal lobe can conjure up vivid memories from the earlier life of the patient ( episodic memory ). Evidence like this can help theories to be produced on memory.
The best source of evidence for the relationship between brain and behaviour comes from studies of brain damage or accidental brain lesions (e.g. damage caused by stroke or gunshot wounds). Neurons at the damaged area die and the changes in behaviour suggest differences from normal functioning.
One famous case of brain lesions is the story of Phineas Gage. He suffered accidental damage to his brain, mostly to the left frontal lobe. He survived and although his behaviour showed no alteration intellectually nor in linguistic ability there were some changes in his personality : he became egoistic and capricious and started to use bad language which was out of character.
Evidence today about the frontal lobes suggest that this part of the brain is concerned with holding in check emotional expressions. With Gage this part was gone or damaged and he showed some loss of control of behaviour ( Damasio, 1996; Macmillan, 1986, cited in Phoenix 2002 ).
Psychologists can study circumstances when the prefrontal cortex is most active in normal participants. This method helps them to create theories on what this region of the brain does (e.g. if a certain part of the brain is damaged or taken out of action, behaviour changes as a result).
In some cases scientists have inflicted damage to the brain in non-human animals, causing experimental lesions where parts of the brain is damaged deliberately and the effect observed. This is a controversial approach and raises serious ethical issues.
An advancing non-invasive method for studying the brain's activity is brain imaging (e.g. PET scan) where both the brain's structure and the amount of blood flow to different regions are studied. Participants engage in psychological tasks and the activity in a certain area of the brain
associated with the task can be measured (e.g. activity is measured in the
occipital lobe that is responsible for processing visual information in the temporal lobe during a visual task).
To start the technique, a radioactive substance or tracer (e.g. an isotope of oxygen ) is introduced into the body ( Myers, Spinks, Luthra and Brooks 1992, cited in Phoenix, 2002).
The presence and location of the tracer is monitored. The brain regions where neurons are most active accumulate the most tracer.
This technique can reveal relationships between brain functioning, the different regions involved and psychological phenomena.
All of the above evidence shows that there is an important link between biology, physiology and psychology.
Individual neurons form neural systems and this is related to an understanding of the brain. The different methods and techniques allow psychologists to construct theories of brain functioning and also illuminate the relationships between the brain and behaviour.
Studying the structure of the brain and careful description of what is seen (e.g. PET scans ), comparing normal brain activity with damaged brain functioning all can reveal more and more about the brain and also about our behaviour.