Sensory experience powerfully shapes cortical sensory representations during an early developmental "critical period" of plasticity. In the rat primary auditory cortex (A1), the experience-dependent plasticity is exemplified by significant, long-lasting distortions in frequency representation after mere exposure to repetitive frequencies during the second week of life. In the visual system, the...

Synaptic circuits are highly sensitive to sensory experience during a critical period in early development. The maturation of GABA inhibition in the visual cortex is suggested to be required for both the onset and closure of the critical period for ocular dominance (OD) plasticity, although the underlying mechanism is unclear. This study examines a model of a visual cortical cell to investigate...

The role of age in second language (L2) acquisition is a subject of much debate. The paper is to examine the role of age in L2 acquisition. In this context, the paper firstly introduces Lenneberg’s (1967) Critical period hypothesis, then further development of the hypothesis made by Johnson and Newport (1989) is offered. Following this, Felix’s (1994) Competition Model and Bley-Vroman’s (1990) ...