Ways Of Studying The Brain Flashcards
What are post mortem evaluations
Psychologists may study interesting behaviours of alive yute. When they die, psychologist will look for abnormalities in their brain that might explain their behaviour. Post Mortem studies have found a link between brain abnormalities and psychiatric disorders, e.g. there is evidence of reduced glial cells in the frontal lobe of patients with depression
Strenght post mortem
Allows for more detailed medical examination of anatomical and neurochemical aspects of the brain than would be possible with other methods of studying the brain. It allows for examination of deeper regions like hippocampus and hypothalamus
Weaknesses post mortem
Lack validity - people die in a number of different ways and at varying stages of disease affecting the structure of the brain. Similarly, the length of time between death and post mortem, and drug treatments can all affect the brain
Post mortem studies have very small sample sizes. This means they can’t be representative,of the target population and so it is problematic to generalise findings to wider population
What is Functional Magnetic Resonance Imaging?
Provides an indirect measure if neural activity by using magnetic fields and radio waves to monitor blood flow in the brain. It measures the change in energy released by the haemoglobin, reflecting activity of the brain to give a moving picture of the brain. Activity in regions of interest can be compared during a base line task and then during a specific,activity
Strengths fmri
It captures dynamic brain activity as opposed to a post mortem examination which purely shows the physiology of the brain
They have good spatial resolution
Weakness of fmri
Interpretation of fmri is complex and is affected by poor temporal resolution, bias and by the base line task used
Research is expensive, Leading to reduced sample sizes which negatively impact the validity of the research.
What does electroencephalogram do
Directly measures general neural activity in the brain, usually linked to states such as a sleep and arousal. Electrodes get placed on scalp and detect neuronal activity directly below where they were placed. Different numbers of electrodes can be used depending on focus of research. When the electrical signals from the electrodes get graphed, the final thing is an EEG. EEG patterns of those with epilepsy show spikes in electrical activity. EEG of those with brain injuries show a slowing of electrical activity.
Strengths,EEG
Useful in clinical diagnosis - for instance it can record the neural activity associated with epilepsy so that doctors can confirm the person is experiencing seizures
They are also cheaper than an fmri so can be used more widely in research
Weakness EEG
Poor spatial resolution
Event related potentials
Electrodes are placed on scalp and directly measure neural activity below the electrodes in response to a specific stimulus introduced by the researcher. ERPs are difficult to pick out from all the other electrical activity being generated from the brain. to establish a specific response to a target stimulus requires many presentations of this stimulus and the responses are averaged together. Extraneous neural activity that is not related to stimulus will not occur consistently, whereas activity linked to stimulus will.
Strengths ERP
Cheaper than fmri so used more in research
Good temporal resolution
Weakness ERP
Poor spatial resolution
Only strong voltage changes across scalp are recordable. Important electrical activity occurring deeper in the brain is not recorded. The generation of ERPs tend to be restricted to neocortex
