The development of neural circuits is influenced by sensory experience during restricted critical periods early in life. A novel critical period is demonstrated for plasticity of the whisker map in layer 2/3 of rat primary somatosensory cortex. Sensory experience during this period guides initial formation of whisker receptive fields.

introduction lentil (lens culinaris medik.) is an important legume in the mediterranean area. high protein content in lentil seed (about 22-28%) makes it as a good food source for developing countries and low-income people. in the west of iran such as kermanhah province, it is the most important pulse in rainfed systems cultivated traditionally in rotation with wheat and barley. lentil is grown...

We study the critical behavior of period doublings in N symmetrically coupled area-preserving maps for many-coupled cases withN > 3. It is found that the critical scaling behaviors depend on the range of coupling interaction. In the extreme long-range case of global coupling, in which each area-preserving map is coupled to all the other area-preserving maps with equal strength, there exist an i...

The critical period for language acquisition is often assumed to be nothing more than a by-product of development. However, evolutionary computer simulations show that it can be explained as a result of biological evolution (Hurford, 1991). In the present study the aim is not to explain how and why this age sensitivity evolved but to investigate the consequences of this individual-level disadva...

Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interfe...

In this study, we examined the perceptual learning of lexical tones in Mandarin Chinese by American young adults, and children from 6 to 14 years old, covering the age range surrounding the “critical period”. The participants received a two-week computerized Mandarin tone training program designed to be child-friendly. The results showed that, for the trainees in each of the four age groups but...

Given the general failure experienced by adults when attempting to learn a second or foreign language, many have hypothesized that a critical period exists for the domain of language learning. Supporters of the Critical Period Hypothesis (CPH) contend that language learning, which takes place outside of this critical period (roughly defined as ending sometime around puberty), will inevitably be...

The language acquisition period in humans lasts about 13 years. After puberty it becomes increasingly difficult to learn a language. We explain this phenomenon by using an evolutionary framework. We present a dynamical system describing competition between language acquisition devices, which differ in the length of the learning period. There are two selective forces that play a role in determin...

Learning increases the number of immature neurons that survive and mature in the adult hippocampus. One-week-old cells are more likely to survive in response to learning than cells in animals that are exposed to training but do not learn. Because neurogenesis is an ongoing and overlapping process, it is possible that learning differentially affects new cells as a function of their maturity. To ...