History + Methods Flashcards
Different kinds of neuro based professions (4)
- -Psychologist: Brain behavior relationship
- -ologist: Disorders of the nervous system, anatomical correlations
- -Surgeons: Specialized doctors, surgery of the nervous structure
- -Scientist: Researchers/teachers in the nervous system
Trephining
Surgical removal of part of the skull to access the brain - can be done for medical reasons, like relieving intercranial pressure, or for spiritual reasons like removing spirits
Ancient Greek philosophers’ opinions on the brain (3)
- Hippocrates: the contralateral effects, the neural origin of emotions, demystifying epilepsy
- Plato: notion of mental health, that one can be mentally fit in the same way as they can be physically fit
- Aristotle: the cardiac hypothesis
The Cell Doctrine
Egyptian school of thought: notions of the central nervous system and the difference in sensory and motor neurons
Ventricular localization hypothesis
Ventricles are positioned in the center of the brain, so they must be important.
Galen
- Sensory nerves at front, motor at back (intricate nature of brain organization)
- Established cerebrospinalfluid
- Balance of the humors theory (blood, mucus, yellow bile, black bile$
Spirit/Soul + Anatomical Discoveries
- Versalius: first neurosurgeon, dissected brains and constructed drawings
- Descartes’ mind-body question. In search of the single seat of the soul.
Descartes’ ideology
There is one seat of the soul that controls our being. It’s the pineal gland due to its central placement and contact with multiple brain functions.
Vitalism vs materialism
Spiritual/outer body experience drives out mental existence vs our entire experience is dictated by the physical interactions within our brains
Localization Theory (3)
Phrenology, faculty psychology and cortical localization
Phrenology
The brain is made up of organs, you can see this in the distinction between lobes; size of region = size of ability.
Faculty Psychology effects (3)
- Killed the ‘seat of the mind’ idea
- Increased the emphasis on cortical functioning; cortices are NB in functioning
- Concentrated the study of behavior on the brain
Cortical Localization
- Broca: damage to a particular area resulted in the removal of the ability to speak.
(A very specific kind of cognition is affected, but the rest is spared) - Wernicke: Receptive speech affected
Critics of Cortical Localization
Freud: aphasias can occur from damage to subcortical regions or problems within the connection of regions, not regions themselves
Flourens: ablation; removing a part of the brain and observing changes in behavior. There is equipotentiality.
Equipotentialiy
Removing a piece of the brain can be accommodated for by virtue of the rest of the brain adjusting. The issue is not with location but its size.
Challenged to localisation
Mind-blindness (see/sense objects but don’t register their purpose)
Lesions to association areas and areas in between important cortical regions
Anosognosia
Not recognising the extent of a disorder or deficit
Lashley - mass action
The extent of any behavioural deficit is directly proportional to the amount of the brain removed; multipotentiality of the brain tissue.
Luria’s Functional Model
Based on the process, how people come to get their scores, not interested in simply what score they got.
Hierarchical Model: 3 subsections (integrated theory)
The CNS is divided into 3 functional units
- Brain stem: primitive, survival, no higher order
- Occipital/Parietal: sensory info reception + integration, environment understanding
- Anterior: higher functioning
Hierarchical Model: theories
- Complex decisions made with input from all three units
- Each area has a role in multiple activities
- Plasticity: the brain can change with training/trauma
Neuropsychological inference
The important of the context in which theories are being established
Key assumptions in modern neuropsych
- Cognitive architecture
- Modularity
- Locality
- Distributed processing
- Uniformity
- Subtractivity
Cognitive Architecture
Complex abilities imply combined brain subsystems; elementary abilities require one small subsystem, complex are a sum.
Modularity
Complex functions make use of subsystems that, basically, all only do one basic thing.
Locality
Modules that do similar things will be close to one another, which makes evolutionary sense given it cuts down time and keeps things efficient
Distributed processing
Higher order activities require wide spread brain use, working together from different zones
Uniformity
Everyone’s brain looks the same
Subtractivity
If you take away parts of the brain, you lose cognitive function
Simple association
Doesn’t tell us much as there is a number of reasons why everyone would perform worse at one task
Simple dissociation
Useful, but not hugely so given that it doesn’t allow for a sure distinction given that a single impairment could affect performance in a task.
Double Dissociation
Allows for the comparison between different lesions that are affecting different skills and keeping others in tact. Problem is that you need two different groups with differing lesions and two tests that tap into different cognitive processes
Within/between subject measurements
Between subject measures are difficult to administer across populations (norms only apply in specific circumstances), within subject measures are better but difficult given that info is seldom gathered before the injury.
Single case analysis, Pros and Cons
Pro: you can obtain large volumes of info about the person
Con: generalisability is questionable
Simple dissociation
Useful, but not hugely so. It can’t determine if it’s caused by wide spread deficit
Different kinds of group studies
Disease based & neural malfunction based
Pros and cons of group studies
Diagnosis approach is flawed given the nature of diagnoses, and lesions don’t discriminate.
Best approach to neuropsych
Single case - theory - group case evidence collection - acceptance/rejection of hypothesis
Performance measures
Use of behavioural performance measures, the choice of an appropriate comparison/control group is essential
Complexities of the lesion method
Injury always entails a loss of function and an adaptive response. The emotional nature of the response can have cognitive effects.
Lesions don’t obey boundaries, and we can’t control the adaptive response. Neuroimaging helps.
