critical periods
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Nature over Nurture: Functional neuronal circuits emerge in the absence of developmental activity
During development, the complex neuronal circuitry of the brain arises from limited information contained in the genome. After the genetic code instructs the birth of neurons, the emergence of brain regions, and the formation of axon tracts, it is believed that neuronal activity plays a critical role in shaping circuits for behavior. Current AI technologies are modeled after the same principle: connections in an initial weight matrix are pruned and strengthened by activity-dependent signals until the network can sufficiently generalize a set of inputs into outputs. Here, we challenge these learning-dominated assumptions by quantifying the contribution of neuronal activity to the development of visually guided swimming behavior in larval zebrafish. Intriguingly, dark-rearing zebrafish revealed that visual experience has no effect on the emergence of the optomotor response (OMR). We then raised animals under conditions where neuronal activity was pharmacologically silenced from organogenesis onward using the sodium-channel blocker tricaine. Strikingly, after washout of the anesthetic, animals performed swim bouts and responded to visual stimuli with 75% accuracy in the OMR paradigm. After shorter periods of silenced activity OMR performance stayed above 90% accuracy, calling into question the importance and impact of classical critical periods for visual development. Detailed quantification of the emergence of functional circuit properties by brain-wide imaging experiments confirmed that neuronal circuits came ‘online’ fully tuned and without the requirement for activity-dependent plasticity. Thus, contrary to what you learned on your mother's knee, complex sensory guided behaviors can be wired up innately by activity-independent developmental mechanisms.
Critical periods of plasticity in adult-born neurons
Critical periods for plasticity in the developing auditory system
Cerebro Parental: La biología aun invisible del desarrollo infantil
Desde la investigación en antropología evolutiva, las neurociencias del comportamiento parental y los estudios de cohortes de orfelinatos, los nuevos conocimientos confluyen en la mayor importancia critica del periodo postnatal inmediato para el desarrollo social humano. Surge la explicación biológica de la interdependencia de los cambios comportamentales en los adultos que crían y el recién nacido: Nature of Nurture. Del concepto unidireccional clásico de la necesidad de estimular un cerebro inmaduro, se comienza a comprender la naturaleza de la interacción en red entre el cerebro neonatal y el cerebro parental que también debe ser estimulado. Concebir, engendra y criar son etapas sucesivas de la reproducción pero no indispensablemente continuas. La función parental es primariamente dependiente de la disponibilidad para cuidar al recién nacido.
How the baby learns to see: Critical periods re-visited
Dlx5/6 involvement in the postnatal maturation of cortical parvalbumin neurons during critical periods
FENS Forum 2024
critical periods coverage
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