Ways of Studying the Brain (ERP and Post-mortem) Flashcards
1
Q
What do ERPs stand for?
A
Event-related potential
2
Q
What do ERPs measure?
A
- ERPs are small voltage changes in the brain that are triggered by specific events or stimuli. e.g. cognitive processing of a specific stimulus
- ERPs are difficult to pick out from other electrical activity being generated within the brain at a given time
3
Q
How do ERPs measure?
A
- Stimulus is usually presented hundreds of times as it’s difficult to isolate the activity
- Any extraneous neural activity that isn’t related to the stimulus will not occur consistently, but the activity linked to the stimulus will, making the specific response to the stimulus clearer.
4
Q
What are the two categories of ERPs?
A
- Waves occurring within 100ms after presentation of stimulus are termed ‘sensory’ ERPs as they show an initial response to physical characteristics of stimulus.
- ERPs generated after 100ms reflect how the subject evaluates the stimulus and termed ‘cognitive’ ERPs as they show information processing
5
Q
What is latency in ERPs?
A
Interval between presentation of stimulus and response
6
Q
Give advantages of ERPs
A
- Can monitor the processing of stimuli without a behavioural response. ERPs recordings can monitor ‘covertly’ the processing of a particular stimulus without requiring the person to respond to them
- As ERPs provide a continuous measure of processing in response to a particular stimulus, it determines how processing is affected by a specific experimental manipulation, e.g. during presentation of different visual stimuli
- Shows activity every millisecond, recording in nearly real time (great temporal resolution)
7
Q
Give disadvantages of ERPs
A
- Studies using ERPs have been critcised for a lack of standardisation in method
- As ERPs are so small, it’s difficult to pick up other electrical activity in the brain. It requires a large number of trials to gain meaningful data. This limits the types of questions that ERP readings can answer
- Only strong voltage change is recordable. Important electrical activities deep in the brain aren’t recorded, meaning the generation of ERPs tends to be restricted to the neocortex
8
Q
Why are post-mortem examinations used?
A
- To establish the underlying biology of a particular behaviour
- e.g. researchers may study a person who displays a certain behaviour while they’re alive that suggests possible brain damage
9
Q
What are post-mortem examinations?
A
When a person dies, researchers can study the physical brain to look for abnormalities that might explain behaviour.
10
Q
What’s an early example of post-mortem examinations?
A
Broca’s patient (Tan) had a speech problem and was found to have a lesion in the posterior left frontal lobe in a post-mortem examination
11
Q
Give example of a disorder that has been found with post mortems
A
- Iverson found higher levels of dopamine in deceased schizophrenics brains compared to non-schizophrenic
- These allow detailed study of neurochemical and neuroanatomical aspects of the brain
12
Q
Give advantages of post-mortem examination
A
- Allows for a detailed examination as it enables researchers to examine deeper regions of the brain like the hypothalamus and hippocampus.
- Harrison claims post-mortem has played a central part in understanding the origins of schizophrenia. He suggests that due to post-mortem, researchers have discovered structural abnormalities of the brain
13
Q
Give disadvantages of post-mortem examination
A
- There are confounding variables. People die in various ways, at various stages of disease. Similarly, the length of time between death and post-mortem, drug treatments and age at death can influence the post-mortem brain
- It’s limited as it’s retrospective because the person is already dead. As a result, the researcher can’t follow up on anything that rises from the post-mortem concerning a relationship between brain abnormalities and cognitive functioning
