Localization of Function
Localization of Function
The concept that specific brain regions are responsible for distinct psychological functions.
Key Concepts
- Strict Localization: The idea that a specific part of the brain is solely responsible for a given function.
- Relative Localization: Suggests that while certain areas are specialized, other areas may also contribute to the same function.
- Distributed Processing: The concept that functions are spread across multiple brain regions.
Historical Studies
Broca's Area (Speech Production)
Aim: To investigate the role of the left frontal lobe in speech production.
Method: Case study of a patient named "Tan", who could only say the word "tan" but understood language.
Results: Broca discovered a lesion in the left inferior frontal gyrus , now known as Broca's area.
Conclusion: This area is critical for speech production.
Wernicke's Area (Language Comprehension)
Aim: To identify brain regions responsible for language comprehension.
Method: Case studies of patients with language deficits.
Results: Lesions in the left posterior superior temporal gyrus led to impaired comprehension but fluent speech.
Conclusion: This area, now called Wernicke's area , is essential for understanding language.
Key Study
Maguire et al. (2000)
Aim: to see if there was any structural changes in the brain after being experienced with navigation
Method: 16 right handed London taxi drivers and 50 non taxi drivers (control group) participated in an MRI scan.
Findings: posterior hippocampus was bigger than the control group, and the anterior hippocampus was smaller. also that the longer someone was a taxi driver, the bigger the differences were.
Conclusion: extensive practice of navigation and spatial memory causes structural changes in the brain
This is a more modern example of localization of function.
Evaluation
Strengths
- Empirical Evidence: Studies like Broca's and Maguire's provide strong support for localization.
- Clinical Applications: Understanding localization aids in treating brain injuries and neurological disorders.
Limitations
- Oversimplification: The brain is highly interconnected, and functions often involve multiple regions.
- Neuroplasticity: The brain can reorganize itself, challenging the idea of strict localization.
Karl Lashley studied rats in the 1950s and found that despite lesioning up to 50% of their brain, their ability to learn and navigate a maze was not affected, which does not support localization of function.
Critical Thinking
- How does neuroplasticity challenge the theory of localization?
- Can localization explain complex behaviors like creativity or empathy?
- Define localization of function.
- What would happen to someone if they damaged Broca's area but not Wernicke's area? How does this link to localization?
