Healthy Brain Development May Be a Matter of Timing

FRIDAY, Jan. 7, 2011 (HealthDay News) -- Researchers have found that brain cells need to create links early in their existence, when they are physically close together, in order to ensure successful brain-wide connections throughout life.

Bloomberg BusinessWeek
http://www.businessweek.com/lifestyle/content/healthday/648578.html

It has long been understood that the first connections in the brain created in the early days of development can be formed over long distances using guidance signals to direct nerve fibres to their correct positions – known as axonal guidance. Subsequently, other connections can follow those pioneer fibres to a target location creating connections between distant parts of the brain. Through these long-distance connections different kinds of information, such as sound and vision, can be integrated.

An early mechanism opens up the possibility that changes in long-distance brain connectivity, that are observed in children and young adults with brain disorders, arise earlier during brain development than previously thought.

http://www.eurekalert.org/pub_releases/2011-01/nu-ie010511.php

This new mechanism differs from the previous model for long-distance connectivity. An axon is a fibre that is extended from one nerve cell and, after travelling through the tissue, can contact several other nerve cells. Normally, axons would grow in a straight line. For several targets, however, the axon has to travel around obstacles, as a straight connection is not possible. In such cases, cells along the way can release guidance cues that either attract or repulse the travelling axon. One example of bended fibres is the visual pathway that at several points takes a sharp 90-degree turn to arrive at the correct target position.

http://sciencetechnologyblog.com/technology/timing-is-everything-in-ensuring-healthy-brain-development/