MCAT® ExamPsychological, Social, and Biological Foundations of BehaviorMedium
A researcher is studying the development of language in infants. They present infants with various speech sounds and measure their brain activity using fMRI. They observe that 6-month-old infants show activation in both Broca's and Wernicke's areas when hearing speech, but by 12 months, this activation becomes more specialized and lateralized to the left hemisphere. This developmental change best illustrates which of the following principles of brain development?
- ANeurogenesis
- BExperience-dependent plasticity
- CSynaptic pruning
- DMyelination
Show answer & explanationAnswer & explanation
Correct answer: B. Experience-dependent plasticity
Experience-dependent plasticity refers to the brain's ability to change and adapt in response to specific experiences. The specialization and lateralization of language areas as infants are exposed to and process speech sounds is a prime example of how neural circuits are refined by environmental input.
Why the other options are wrong
- A. Neurogenesis is the birth of new neurons, which primarily occurs prenatally and in specific regions postnatally, not directly explaining the functional specialization of existing areas due to experience.
- C. Synaptic pruning is the elimination of unnecessary synapses, which is a part of brain development, but the scenario focuses more on the refinement and specialization of active pathways through experience, rather than just elimination.
- D. Myelination is the process of forming a myelin sheath around nerve fibers, increasing the speed of nerve impulse conduction, but doesn't specifically explain the specialization of function based on experience.
Experience-Dependent Plasticity
The ability of the brain to change and adapt its structure and function in response to specific environmental experiences, learning, and skill acquisition.
- Involves strengthening or weakening of synaptic connections.
- Leads to specialization of brain regions.
- Underlies learning and memory throughout life.
- Different from general experience-expectant plasticity.
Memory trick: Brain's Building Blocks: Myelin, Synapses, Neurons, Experience.