effects of brain damage and brain stimulation Flashcards
what is the main limitation about making inferences from brain imaging?
example?
how to resolve this?
examples?
even if a part of the brain is active during a task, it doesn’t mean it is causing the behaviour
e.g might be a ‘back-up’ or involved in the learning of the task
therefore have to examine whether beh. is affected when activity is disrupted and if it is then it is necessary for functioning
e.g in animals produce lesions and in humans, through neurosurgery, stroke, trauma and tumors, degeneration or infection
what is neuropsychology?
and when did it begin?
area of psychology which examines the effects of brain damage on abilties and behaviour
19th century with Broca
decsription of Broca’s work?
through studying of tan who had aphasia (impaired speech) was able to establish that lesion in left inferior frontal lobe results in language impairments
describe split brain research findings?
conducted by Sperry and Gazzaniga on epileptic patients whose corpus callosum had been cut
found localisation of language heavily biased towards left hemisphere as when presented to LVF (connected to right hemisphere) couldn’t say what they saw but could draw it
describe hemispatial neglect?
people can see everything but they only attend to one hemisphere and therefore only one visual field due to damage in right parietal lobe
reveals localisation of attention system as can viw area damaged
what was the result of HM having a temporal lobe resection (removal of a section of it)?
anterograde amnesia - no new episodic memories
partial retrograde amnesia - recalled childhood but not years before surgery
working memory normal
procedural (skills) and lexical (words) memory normal
what are the 2 approaches to neuropschology?
- classical neuropsyhcology - localisation
2. cognitive neuropsychology - dissociations
what does double dissociation mean and name an example?
when two related mental processes are shown to function independently of each other
e.g recognition and writing of vowels and constants is impaired differently in differnt people (some can’t cope with vowels and some can’t cope with consonants)
what is a single dissociation and what is an example of it?
where one cognitive abillity is impaired and the other related one is intact so partially independent
e.g struggle in writing vowels not consonants but could just be due to easier differentiation (not different ways in which they are processed)
what is a strength of neuropsychology?
enables causal inferences to be made
what are 2 limitations of neuropsychology?
lesions due to trauma or degeneration are rarely anatomical (tend to affect multiple brain regions)
brain damage associated with changes effecting cognitive performance so hard to spearate from effects due to damage in specific region
what is the function of TMS and how does it work?
attempts to model effects of brain damage or help treat certain conditions e.g depression and Parkinson’s
current in coil of wire generates magnetic field in the brain which generates currents in neurons
causes disorganised activity in area as neurons randomly fire (either excitatory or inhibitory) so impaired performance
what does TMS over pirmary motor cortex and primary and secondary visual cortex result in?
primary motor cortex - muscle contractions
primary and secondary visual cortex - perception of flashing patterns (phosphenes)
what is TMS often referred to as?
a virtual lesion technique as produces similar effects to that of a brain lesion (impaired performance due to disorganised activity caused by magnetic field)
what are the 3 inferences which can be made from TMS?
functional-anatomical: is area essential for performing a task
chronometric: what time does stimulation of area affect performance
process interaction: if disrupting 1 process improves another, shows they normally compete
