Studying The Brain Flashcards
Post mortem examination
When a person dies the psychologist removes the brain from the body and dissects it and looks for abnormalities, they allowed for more detailed examination of the anatomical and neurochemical which can’t be observed otherwise this also applies for the deeper regions of the brain such the hippocampus system hypothalamus which can also only be observe this way
But the sample size is very small due to the permissions needed, also people die in many different circumstances and the time between death and lost mortem and drug treatments can all affect the brain.
Functional magnetic resonance imaging (FMRI)
This uses magnetic uses magnetic fields and radio waves to monitor the blood flow in the brain, it measures the change in energy released by haemoglobin showing the brains oxygen consumption. It gives a moving picture of the brain and shows dynamic brain activity unlike an MRI or post-mortem.
The temporal resolution of FMRI is not perfect making the interpretation of it difficult, it is also expensive leading to reduce sample size reducing the validity of the research
Electroencephalogram EEG
EEG measures the general electrical activity in the brain linked to states such as sleep and arousal, electrodes are placed on the scalp and detect neuronal activity bellow where they are placed, the number used depends in the research. The electrical signals for the electrodes are graphed over time called an EEG pattern. The EEG patterns of people with epilepsy shows spikes of activity and for those with brain injury there is a slowing of electrical activity.
An EEGi useful in clinical diagnosis as it can determine the cause of seizures wether it is psychological or epileptical, it is also cheaper can be used for research more easily. But they have poor spatial resolution so it is hard to detect small measurements
Event related potentials
Electrodes are placed on the scalp and can detect neuronal activity in response to a specific stimulus introduced by the researcher, the event related potential are difficult to pick out from other brain signals so the stimulus has to presented many times and the responses have to be averaged. ERP waves generated in the first 100 milliseconds after a stimulus is presented are termed sensory ERPs as they reflect the initial response to the stimulus’s physical characteristics while those after reflect how the stimuli is evaluated and are called cognitive ERPs.
It can measure the processing of a stimulus even if there is no behavioural response so it can covertly measure the processes of a stimulus.
However only sufficiently string voltage changes generated across the scalp are recordable, important electrical activity deeper in the brain is nit recorded,so it is constricted to the neo cortex
