Localisation & Neuroplasticity Flashcards
Maguire et al (2000)
- investigate effect of extensive navigation of brain structure –> if more GM found in certain region, may indicate localisation
- 16 male taxi drivers, 50 non-taxi drivers
- more G.M for taxi drivers in POSTERIOR HIPPOCAMPUS, more G.M. for non-taxi drivers in ANTERIOR HIPPOCAMPUS
- Posterior hippocampus stores a spatial representation of the environment –> SPATIAL MAPPING of ENVIRONMENT
MRI USED
STRENGTHS of Maguire et al (2000)
- lab experiment + objective + technical equipment + quantitative data = high internal validity
- use of MRI allowed for differentiation b/w size & structure of dif brain regions
LIMITATIONS of Maguire et al (2000)
- theories of localisation are biologically reductionist in nature and try to reduce very complex human behaviours and cognitive processes to one specific brain region.
- more thorough understanding of the brain is required to truly understand complex cognitive processes like language.
- quasi-experimental (SUFFERS FROM BIDIRECTIONAL AMBIGUITY)
- lack of control over environment
Antonova et al (2011)
- how ACh inhibitors (scopolamine) affect spatial memory
- 20 men
- experimental, randomised double-blind procedure
- random allocation to scopolamine injection group or placebo group
- virtual reality maze game, fMRI, 3-4 weeks later returned & put in opposite groups
- ACh inhibitors = less activation of hippocampus, worse memory
- navigation memory is localised to hippocampus
STRENGTHS of Antonova et al (2011)
- use of fMRI to determine brain activity
- COUNTERBALANCING for practice effect
LIMITATIONS
- During the debriefing, several of the participants expressed that they had felt stressed, either as a result of the injection of an unfamiliar drug or being in the fMRI enclosure.
- This could have an effect on the working of the hippocampus as we know that stress may interfere with memory encoding
- ONLY MALES = ETHNOCENTRISM –>
idea of localisation fails to take into account individual differences.
suggests a level of BETA BIAS in the theory: the differences between men and woman are ignored, and variations in the pattern of activation and the size of areas observed during various language activities are not considered.
EVALUATION OF LOCALISATION (KARL LASHLEY –> EUIPOENTIALITY THEORY)
- karl lashley falsified pre-existing, somewhat reductionist theory –> more holistic
- very complex tasks like learning a maze will inevitably involve a large number of neural networks in order to deal effectively w/ the task
- Methods other than memory were not inhibited (e.g. smell) to find food in maze
What is the equipotentiality theory?
- suggests that the basic motor and sensory functions are localised, but that higher mental functions are not.
- intact areas of the cortex could take over responsibility for specific cognitive functions following brain injury.
- functions are not localised to just one region, as other regions can take over specific functions following brain injury
What did Dronkers et al (2007) find?
- he conducted an MRI scan on Tan’s brain
- although there was a lesion in Broca’s area, also found evidence to suggest OTHER areas may have contributed to failure in speech production
- Broca’s area may not be the only region responsible for speech production
What did you want to say before mentioning Antonova’s study again??
could involve the FUNCTION of different neurotransmitters that act on certain regions of the brain
LOCALISATION INTRO
Mechanics have weekly brain lesions. The issue is they’re not always easy. They’re better now with new additions.
Conclusion of localisation
The main strength of the theory of localization is that it provided the basis for development of the theory of distribution of function and the concept of a network of activity through multiple neural pathways. The evidence from all of
these lead to the conclusion that while human behaviour can be localized in one area, which makes the theory valid, it does not necessarily have to be.
