Cognitive Neuroscience Flashcards
how do we use the damaged brain to learn about the healthy brain?
we study people with brain damage in certain areas and compare them to people without damage in order to draw conclusions about what the damaged area of the brain does e.g. Phineas Guage
why should we study the brain?
studying the brain at a neural level allows us to understand cognitive processes and help when disorders arise
how do brain scans allow for communication?
EEG and fMRIs have allowed (some) communication with people in vegetative states as they can compare the ‘yes’ and ‘no’ brain activity to that of a healthy subject
how do we research cognitive function and neural activity?
to measure their relation to each other, we can either:
- change behaviour and see its effect on the brain
- or change the state of the brain and see its effect on behaviour.
recording methods
manipulating behaviour and measuring brain activity = correlation technique
inference methods
manipulating brain state (testing people with lesions) and measuring the effect on behaviour = causal technique
are inference or recording studies better?
inference studies allow stronger inference about necessity of a brain region but recording studies allow for greater flexibility in experimental design and are often a richer data source
why do we need different techniques of measuring the brain?
each technique is good for something but poor in something else - sometimes combining multiple brain measuring techniques yields the best result = converging evidence
classical neuropsychology
an approach that involves mapping brain areas to cognitive functions
- typically performed at a group level
- good at answering clinical questions
cognitive neuropsychology
an approach that involves determining whether functions dissociate under damage
- often relies heavily on case studies
- focuses on cognitive processes
- doesn’t require information on where the damage is
what is a single dissociation
we find a patient with a impairment in on aspect of cognition e.g. they can read easy made-up words but struggle difficult regular words.
this does not allow us to conclude anything as reading irregular words might just eb harder than non-words. we need a double dissociation to make conclusions
what is a double dissociation
if we want to rule out the difficulty of a task as a factor influencing a patients performance, we need to find another patient who displays the opposite deficit to the original.
for example, if patient X can read non-words but struggles with irregular words, we need to compare them to a patient Y who struggles with non-words but can read irregular words.
this would allow us to conclude that the systems that deal with irregular words and non-words are separate in the brain.
assumptions in single case research
fractional assumption = brain damage can selectively affect different cognitive/neural systems
transparency assumption = brain lesions can affect existing cognitive systems but do not create new systems
universality assumption = all cognitive systems are the same
dual route model of reading
- connectionist ‘triangle’ model suggests we read semantically (we have to activate the meaning of irregular words in order to read them)
dual-route cascaded model suggests we use lexical representations to read irregular words
neuropsychology could help solve this debate
neuropsychology and reading in people with dementia
100 observations in semantic dementia:
- Impaired semantic knowledge of word meanings
- Poor irregular word reading
Suggests that semantic knowledge is necessary to pronounce irregular words correctly
BUT what if patients have damage to separate semantic and lexical systems that are close to each other in the brain?
this is where single case studies come in (EM)
