Introduction to special issue

Neuroscience: Systems-Level Brain Development

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Science  04 Nov 2005:
Vol. 310, Issue 5749, pp. 801
DOI: 10.1126/science.310.5749.801

Our brains show the highest degree of plasticity during the early phases of life. However, not all is lost as we advance in years. A certain level of flexibility and adaptability will be with us throughout life. To fully understand the operations and functions behind these processes, it is not enough to concentrate solely on the molecular and cellular components and their interactions. Nor, at the other end of the spectrum, is the study of higher cognitive functions sufficient: It is often too remote to provide comprehensible mechanistic insight. The leap from cells to thought seems almost infinitely complex, yet every growing child manages to make it. Somewhere in this middle ground, between molecular components and psychology, lie the means by which familial and educational experiences intersect with developmental biology to shape cognitive abilities and personalities. We have thus decided to focus on the systems level instead. This approach has been extremely successful over the years and provided us with a wealth of novel and sometimes astonishing insights.

Sur and Rubenstein (p. 805) set the stage by laying out the framework and controversies within which these questions are presently discussed. They review both the molecular signaling events that underlie early cortical area specification and recent advances in understanding the postnatal shaping of circuits by neuronal activity. Feldman and Brecht (p. 810) describe how certain patterns of sensory activity as well as inactivity elicit multiple, functionally distinct forms of map plasticity in the somatosensory cortex. In a Viewpoint, Sakai (p. 815) discusses the literature on language systems in the mature human brain, with particular emphasis on cortical plasticity during secondlanguage learning. In another Viewpoint, Baron-Cohen et al. (p. 819) present data in support of their hypothesis that autism may be an extreme manifestation of the male brain and discuss the mechanisms that might explain these observations.

A News story (p. 802) by Bhattacharjee describes progress in establishing gene-brain-behavior connections in Williams-Beuren syndrome, a neurodevelopmental disorder in which affected individuals are excessively social but typically suffer from mental retardation.

At Science's Signal Transduction Knowledge Environment (STKE,, the focus shifts to cell and molecular levels. A Teaching Resource by Blitzer on long-term potentiation, a Review by Ron and Jurd on addiction, and a Perspective by Alger on endocannabinoids all address molecular mechanisms of physiological or pathological neuronal plasticity. In other Perspectives in neuroscience, Noon and Lloyd describe a pathway by which the pathogen that causes leprosy subverts the normal response to injury to drive excessive proliferation of Schwann cells.

A Perspective in the Science of Aging Knowledge Environment (SAGE KE, by Jan de Fockert discusses recent results that suggest that cognitive aging is associated with a reduced ability to separate relevant and irrelevant information.

Science's Next Wave profiles stellar early-career neuroscience researchers in North America and Europe, exploring their successes to date. Meanwhile, GrantsNet highlights the latest neuroscience funding opportunities.

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