lecture 6 - neuropsyc intro Flashcards
what is neuropsychology
Study of the link between brain and behaviour
* Fundamentally about studying impairments in
individuals who have suffered brain damage
what are some causes of brain damage
- Traumatic injury (car accidents, falls, projectile)
- Stroke (leading cause on non-traumatic injury)
- Lack of oxygen (hypoxia)
- Tumors
- Brain infections or inflammation (e.g., encephalitis, hydrocephalus)
- Nutritional deficiencies
- Chronic alcohol abuse (e.g., Korsakoff’s syndrome)
- Surgery (e.g., intractable epilepsy)
clinical neuropsychology vs cognitive neuropsychology
Both concern impairments in normal functions in the brain / brain damage
* Clinical neuropsychologists are interested in understanding the
impairment
* Cognitive neuropsychologists are interested in learning about
normal functions from studying the impairment
what do clinical neuropsychologists focus on
Focus on assessment (diagnosis and prognosis),
management and rehabilitation for patients
* Define pathological conditions/characterise deficits considering cognitive, behavioural, emotional and social aspects
focus of cognitive neuropsychology
-the two types of cognitive neuropsyc
Understand normal functions in the brain by
studying patterns of impairment after brain damage
* Map functions to brain regions
* Two types of cognitive neuropsychology:
* Strong: start out with no theory and use patient data to infer / construct theory
* Weak: use patient (damaged brains) data to constrain / refine theory, (could be a theory developed by already studying a healthy brain)
Assumptions in cognitive
neuropsychology
- Universality
- Modularity
- Fractionation
- Transparency
need to understand these if were gonna use damaged brains to understand our brains
assumption of universality
Cognitive processes are the same in all individuals
-the way our brains are organised are roughly the same
-will find same building blocks for the same processes
-Still some scope for individual differences but the average of a group of individuals should be a
good reflection of any individual in the wider population
-the assumption is not that brains are identical, we just have same architecture
assumption of modularity
Complex cognitive processes can be broken down into simpler processing units
-can break individual processes in the brain into a series of steps
assumption of Fractionation
-more important in neuropsyc
Brain damage can result in the selective impairment of a particular cognitive process
-you can selectivley impair one of your cognitive processes in the brain, and if you do that you them removed or impair the behaviour associated with the process
assumption of Transparency (aka subtractivity)
The cognitive system of a brain-damaged patient is fundamentally the same as that of a normal subject except for a “local” modification of the system = all other processes are intact
-the impairment shouldnt impair other functions in the brain
-otherwise healthy and intact brain
are these assumptions justified
fractionation
modularity
these two assumtpions are hard to justify in terms of evidence but can be justified by theory
-hard to show modularity is right or not
-fractionation- do have many patients to show this so cant necessarily argue against
are these assumptions justified
-universality
structure
function
structure
-the way it looks is shown to be similar in images
-the lines (sulci) they key lines are roughly the same but do vary a bit
-all brains have 2 halves (not identical) , tend to have more mass in the left front and more mass in right back.
function
-when you look at activity in the brain, eg fmri studies , group study, showing average activity,
-often find that the most active site across all participants is responsible for that function
-photos show 9 healthy individuals brains doing a word recognition task
-red circle indicates most active location, their is much variation
-shows there is variation of function in brain
are these assumptions justified
transparency
-adapting to brain damage,
Marotta, Genovese &
Behrmann (2001)
*Disruption to the cognitive
processes
-often find that problems are not just in one cognitive process, eg people who struggle to recognise faces sometimes also cant recognise objects well
-brains can adapt to the damage
* Behavioural compensation 9find behavioural solution)
* Neural re-organisation (re organise things in the brain)
adapting to brain damage
-behavioural compensation
-neural re organisation
example of adapting by behavioural compensation
-patient with visual object agnosia
-given picture of apple asked to identify it
-you see in the end he succesfully identifies the apple, but not in the method in the normal we do
-he used a different behavioural strategy, he figured if things have corners and edges etc then they’re likely to be manmade
example adapting by neural re organisation:
-the same brain scanned at differnt times
-one photo shows damage in the inidvidual , have localised damage in right hemispeher, where face recognition tends to happen
-in the other scan its shown that activity is spread out when looking at faces, has learnt to recognise faces still, but activity goes on also in left hemisphere (not normal place thats active when recognising faces)
are these assumptions justified
transparency
-pre surgery brain function
-other surgical damage
-sometimes brain damage is caused by surgery
-the two halves of brain have been researched by looking at split brain patients, patients 2 hemispheres dont communicate (through surgery the corpus callosum is cut maybe bc eoilipsy etc)
-2 halves of brain operate independently - these have been studies
-the assumption here is that once the fibres are cut, the way the brain is organised should be normal (in an individual who has not had normal activation because of uncontrolled firing) is this fair? we dont know.
-after patient died they realised the surgery had caused other brain areas damage , evidence of stroke eg, also found metal clips in his brain, that corroded and damaged the tissue in the brain
