Reading focus
Syllabus: How Do Brain and Body Support Mind and Behavior?
Track which processes change, at what age, and in which species, rather than treating plasticity as one quantity.
Why you’re reading it. Connect developmental explanation with mechanisms that can alter neural organization.
A question to consider. Two experiences produce opposite changes in a synaptic measure but both improve performance. Why would that challenge a simple ‘more is better’ interpretation?
Why this reading
Plasticity is often treated as a general promise that experience can improve the brain. Kolb and Gibb offer a more discriminating account: what changes depends on developmental timing, the kind of experience, the neural measure, and the system being studied. Change need not be beneficial.
Before you read
Plasticity means a capacity to change in response to experience or other conditions. Neurogenesis produces neurons; synaptogenesis forms connections; pruning removes some connections; myelination changes the insulating covering of axons. These processes differ, and none is equivalent to an increase in a brain scan's gray-matter estimate. A sensitive period is a time when particular experience has especially strong effects on a developing system.
Read for
- Compare the levels at which neural change is measured, from molecules and synapses to anatomy and behavior.
- Track when similar experiences have different effects at different ages or in different regions.
- Keep the species and experimental conditions attached to each conclusion, especially when the discussion moves from rats to humans.
Consider afterwards
- Would more synapses necessarily imply better functioning? Use the developmental argument to explain.
- What evidence would be needed before turning an animal enrichment result into a recommendation for children?
Editorial context
The review relies heavily on laboratory rats and emphasizes cerebral development. Its examples are not clinical or educational prescriptions, and its developmental timings should not become universal deadlines. Human adult neurogenesis also requires distinct evidence: later work examines molecular signatures in post-mortem hippocampal tissue. Such findings do not mean that every experience-related MRI change represents new neurons or establishes their causal contribution to cognition.