What is the critical period? Also known as the sensitive period, the critical period is a time during early postnatal life when the development and maturation of functional properties of the brain, its ‘plasticity’, is strongly dependent on experience or environmental influences. The concept of a critical period therefore plays an important role in the ageold nature versus nurture debate — to w...

Neuronal circuits are shaped by experience during critical periods of early postnatal life. The ability to control the timing, duration, and closure of these heightened levels of brain plasticity has recently become experimentally accessible, especially in the developing visual system. This review summarizes our current understanding of known critical periods across several systems and species....

abstract in order to determine the critical period of weed control in euro-flour variety of sunflower (helianthus annus, l.) an experimental was conducted with a randomized complete block design with 10 treatments and three replications in islamic azad university astara-branch-agricultural college in 2006 growing season. experimental treatments were conducted in two sets, the first set included...

The critical period of respiratory development in rats is a narrow window toward the end of the second postnatal week (P12-13), when abrupt neurochemical, electrophysiological, and ventilatory changes occur, when inhibition dominates over excitation, and when the animals' response to hypoxia is the weakest. The goal of this study was to further test our hypothesis that a major mechanism underly...

Cortical circuits in the brain are refined by experience during critical periods early in postnatal life. Critical periods are regulated by the balance of excitatory and inhibitory (E/I) neurotransmission in the brain during development. There is now increasing evidence of E/I imbalance in autism, a complex genetic neurodevelopmental disorder diagnosed by abnormal socialization, impaired commun...