Exam 1 Flashcards
MR - Brain
Why are patient studies useful?
They are a major source of knowledge about the brain and mind
MR - Brain
Define agnosia
Loss of ability to recognize objects, people, sounds, shapes, or smells; that is, the inability to attach appropriate meaning to objective sense-data
MR - Brain
Define aphasia
A general term relating to loss of language ability
MR - Brain
Define apraxia
A general term for disorders of action
MR - Brain
Define amnesia
A lack of mnenomic abilities
MR - Brain
Define Ataxia
Poor coordination and unsteadiness due to failure to regulate the body’s posture, and strength and direction of limb movements
MR - Brain (not essential)
There are many subtypes of neurological disorders such as agnosia, give examples and definitions of three subtypes
Form agnosia - patients percieve only parts of details, not the whole object
Finger agnosia - The inability to distinguish the fingers on the hand. Present following lesions to occipital lobe.
Simultanagnosia - Patients can recognize objects or details in their visual field, but only one at a time
Associative agnosia - Patients can describe visual scenes and classes of objects but still fail to recognize them.
Apperceptive agnosia - Patients are unable to distinguish visual shapes and so have trouble recognizing, copying, or discriminating between different visual stimuli.
Prosopagnosia - also known as facial blindness
MR - Brain
What can the existence of selective deficits tell us?
They can tell us something about the way function is organised in the brain
MR - Brain
Define ‘dissociated’ in terms of cognitive functions
Seperated to a degree from each other through selective impairment
MR - Brain
Dissociation studies require what?
A minimum of two groups and two tasks. Comparison between patient/control groups shows deficit.
MR - Brain
What are the limitations of single dissociation?
In this study, its possible that the poor performance of patients was caused by another factor, such as a deficit in concentration, and that their test of declarative memory required more concentration than our test of nondeclarative.
MR - Brain
What is the benefits of testing for double dissociation?
- Provide strong evidence that there are cognitive processes critical for task X that are not critical for task Y, and vice versa, and that brain area A is critical for task X but not for task Y etc.
- Double dissociations provide evidence that the observed differences in performance reflect functional differences between the groups, rather than unequal sensitivity of the two tasks.
- Participants don’t have to be perfectly intact on either task, they just need to be significantly better at one task than the other
MR - Brain
What are the limitations of patient studies? (5)
- Assumption of modularity
- Lesions extensive and varied
- Lesion anatomy inaccurate, connections not considered
- Individual differences in functional anatomy
- Poor temporal resolution
MR - Brain
Limitations of patient studies: Explain ‘Assumption of modularity/modularity of function’
- Assumption that mental processes occur with a high degree of isolation from other mental processes and when one area is damaged other regions do not adapt their function
- Brain plasticity: In reality the brain reorganizes quickly. Intact regions change their behaviour so it is difficult to infer function of damaged region
- Processes/dynamics neglected: It is neurons, not black boxes, that perform the function - but how?
MR - Brain
Limitations of patient studies: Explain ‘lesions extensive and varied’
- Most work done with patients who have large lesions
- Lesions often damage several function centres, so there are few patients with ‘pure’ deficits
- Lesion size and location variable, hard to find a group of similar patients. Inferences from single patients are weak
- Individual differences in recuperative history
