After providing all the funding for The Brain from Top to Bottom for over 10 years, the CIHR Institute of Neurosciences, Mental Health and Addiction informed us that because of budget cuts, they were going to be forced to stop sponsoring us as of March 31st, 2013.

We have approached a number of organizations, all of which have recognized the value of our work. But we have not managed to find the funding we need. We must therefore ask our readers for donations so that we can continue updating and adding new content to The Brain from Top to Bottom web site and blog.

Please, rest assured that we are doing our utmost to continue our mission of providing the general public with the best possible information about the brain and neuroscience in the original spirit of the Internet: the desire to share information free of charge and with no adverstising.

Whether your support is moral, financial, or both, thank you from the bottom of our hearts!

Bruno Dubuc, Patrick Robert, Denis Paquet, and Al Daigen




Tuesday, 18 June 2013
Proteins That Guide the Wiring of the Brain

The human brain has millions of times more connections between its neurons than the number of genes (roughly 20 000 to 25 000) in the DNA of these cells. And yet, when the brain is developing, the tips of the axons of its growing neurons act like veritable homing devices, successfully seeking out their specific targets in the complex molecular soup that constitutes the extracellular environment.

Scientists have long known that these targets produce molecules that are detected by receptors on the axons’ growth cones and guide them to their targets. But only recently did a team at the Salk Institute in California discover how just a handful of genes enable the guidance processes by which the brain’s complex wiring is established.

The small number of proteins manufactured by these genes arrange themselves into “coreceptors” that can integrate multiple molecular signals and translate them into coherent navigational instructions for the axons’ growth cones.

The Salk Institute study dealt with motor neurons in mice. The axons of these neurons must emerge from the spinal cord and travel to the right muscles in the animals’ paws. But there is a very high likelihood that, as in many other cases, the same mechanisms at work here in the peripheral nervous system also operate in the central nervous system, thus providing one more key to understanding how growing axons navigate in the right direction.

i_lien Complex Wiring of the Nervous System May Rely on Handful of Genes and Proteins
a_lien Ret Is a Multifunctional Coreceptor that Integrates Diffusible- and Contact-Axon Guidance Signals

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