Critical periods in brain development – often called “sensitive periods” – are of great interest to educators. Scientists have found that for some types of skills and knowledge acquisition, the human brain may have built-in cycles, or “sensitive periods,” when more effective learning is taking place. These can be age-related and involve natural developmental processes, although much is yet to be understood about such phases.
New research reported in Nature Neuroscience this week (2017 Dec;20(12):1715-1721. doi: 10.1038/s41593-017-0002-3) discusses how “critical periods are crucial for proper brain development.” Problems during these developmental stages, the scientists report, can cause neurodevelopmental problems with lifelong consequences. They describe that understanding how critical periods are regulated within the brain is therefore of great scientific relevance. A new piece of the puzzle is now added: for critical periods in vision, certain brain circuits in the thalamus are playing a central role in regulation. If the same holds true in people, scientists report this may be highly relevant to improve vision in people affected by amblyopia, the most common cause of decreased vision in a single eye for children and young adults. When the eye and the brain aren’t working well together, the cause can be any condition that interferes with focusing during early childhood. Eye alignment, clouding, absence of eyeglass correction for near- or far-sightedness. Any of these can block the experiences the eye and brain need during this critical period of brain plasticity in vision.
–Kathleen Scalise