Introduction to techniques Flashcards
Which behavioural measures are involved in cognitive and neuropsychological techniques?
Accuracy and reaction time
Define accuracy
How WELL the participant performs in an experiment.
eg how many words can i participant recall in a memory task?
Define reaction time (RT)
A study of mental chronometry. The time taken to respond or complete a task/experiment.
What is the difference between spatial revolution and temporal revolution?
- Spatial revolution = how finely/coarsely a technique samples a spatial location - eg single cell vs 3mm of cortex
- Temporal revolution = how finely/coarsely a technique samples in time - eg 1-3 miliseconds vs 1-2 seconds.
What is the speed-accuracy trade-off?
Mistaking accuracy for speed (RT) or vise versa
Advantages of eye tracking?
- excellent spatial and temporal resolution
- non-invasive
- is becoming more portable and less expensive
Disadvantages of eye tracking?
Just because a participant has fixed on one piece of information, it does not necessarily mean that they have used that information. How do we know that the information is significant?
Why are computer models used?
- They are used to stimulate cognitive processes
- Useful for testing theories of cognition
What is single cell recording?
A micro electrode is inserted into single cells of the brain.
What can single cell recording tell/show us?
- Excellent spatial resolution
- Can show us cells which respond to only colour/motion/size etc.
- can characterize the responses of cells in specific cortical regions
Disadvantages of cell recording in animals?
- damaging parts of an animals brain to determine he regions function - other areas may become damaged too
- There is a limited extent to which animals brains reflect that of a human.
Function and Advantages and disadvantages of ECoG?
Function - measures electrical brain signals
using electrodes implanted on the surface
of the brain of neuropsychology patients.
Adv - great temporal and spatial revolution
Disadv - invasive
What is a single dissociation?
Comparing the performance of a brain damaged patient with a healthy participant.
When a patient perofrms normally on one task but is impaired on another task.
Disadvantage of a single dissociation?
- Participant could simply be finding one of the tasks too difficult.
- there may be an imbalance in the task demands
What is a double dissociation?
The solution to the problem with single dissociation’s
2 patients each perform normally on opposing tasks.
What does Transcranial Magnetic Stimulation (TMS) do?
Temporarily induces a ‘lesion’ in human participants. This is to observe the effects of disrupting neural function on the ability to perform particular cognitive tasks.
Advantages of TMS?
- Good spatial and temporal resolution
- Non-invasive
- Often used in conjunction with other methods such as MRI
Name a couple brain imaging techniques.
- Structure - CT or CAT scanning, MRI
- Functional - Electrical and magnetic: EEG and ERP. MEG - these measure neural events.
Metabolic: PET, fMRI - these measure metabolic changes correlated with neural events
Advantages and disadvantages of EEG’s and ERPs?
ADV - excellent temporal resolution
- inexpensive
DISADV - poor spatial resolution
What is Positron Emission Tomography (PET)?
- measures regional cerebral blood flow (because blood flows to ACTIVE brain areas)
- radioactive positrons follow the blood flow and detect their position, then outputs an image of the brain areas which are active during a particular task.
Advantages and disadvantages of PET?
adv - excellent spatial resolution
disadv - poor temporal resolution, invasive
- correlation does not imply causation
What is Functional Magnetic Resonance Imaging? (fMRI)
- measures blood flow
- blood contains oxygen which has magnetic properties, so a magnet measures the position of blood with high oxygen levels.
Advantages and disadvantages of fMRI?
adv - good spatial resolution, non-invasive
disadv - poor temporal resolution
- expensive
- claustrophobic?
What is Magnetoencephalography (MEG)?
- electric currents measure magnetic brain activity.
- similar to EEG
Advantages and Disadvantages of MEG?
adv - good temporal resolution
disadv - spatial resolution is not as good as fMRI but is better than ERPs.
