Lecture 2 - The Lesioned Brain Flashcards
What is Classical Neuropsychology?
Study of brain and behaviour - what cognitive functions are disrupted by damage to X.
What is Cognitive Neuropsychology?
Seeks to understand normal cognitive processes by studying individuals with cognitive impairments from brain damage
What is split brain surgery
Cuts through the fibers (corpus callosum) of the brain’s two hemispheres
What is an Aneurysm
Localised weak spot / enlargement of the wall of an artery that is prone to rupture
What is a stroke?
Damage to the brain from interruption of its blood supply
What is Ischemia?
Blood flow restricted - lack of glucose / oxygen
What is a Haemorrhage?
Bleeding into brain tissue
What is Hemianopia?
Blindness in one half of the visual field
What is single dissociation?
Being impaired in one task (A) but relatively spared on another task (B)
What is classical single dissociation?
Being impaired in one task (A) but completely spared in another (B) (compared with control)
What is strong single dissociation?
Being impaired in both tasks but one task is worse than the other (A and B may use different cog processes OR one is harder than the other)
Patient CF - Classical single dissociation - Cubelli 1991
Suffered an Ischemic stroke - damage to left parietal area. Couldn’t speak but could communicate through gestures. Wrote with left hand but omitted VOWELS
Kay & Hanley 1994 - classical single dissociation
Patient omitted / made errors with consonants
What do these case studies suggest for classical single dissociations?
Brain has separate neural resources for processing of written vowels compared to consonants - same location but different interspersed neurons. FUNCTIONAL DISSOCIATIONS
What is double dissociation
When two different functions are selectively impaired in separate patients - DISTINCT NEURAL SYSTEMS (processing vowels and not consonants)
Speech aphasia - Julia case study
Could not speak after a stroke, but has re-learnt how to.
Cannot name things she is shown (drawing or picture) but can describe what they are.
What brain areas are involved in Julias case study
Frontal lobe (left) = Brocas area intact (language production)
Temporal lobe = Wernickes area = damaged (language comprehension)
Knech et al., 2000 study - lateralisation
Strong lateralisation of language (left hemisphere) less likely to experience language deficits after unilateral brain lesion COMPARED TO weak lateralisation or bilateral language representation
Problems with single case studies
Everyone is different - no guarantee same lesions will have the same cognitive effects
Group studies - what is good about GROUPING BY SYNDROME?
Good for investigating neural correlates of a disease pathology (ALZHEIMERS)
Group studies - what is good about GROUPING BY BEHAVIOURAL SYMPTOMS?
Identify multiple regions impacted - lesion location - can test predictions from functional imaging
