How neurons get wired.
An unknown mechanism that establishes polarity in developing nerve cells has been discovered by scientists at the University of Arizona, Tucson. Understanding how nerve cells make connections is an important step in developing cures for nerve damage resulting from spinal cord injuries or neurodegenerative diseases such as Alzheimer's.
Doctoral student Sara Parker and her advisor, assistant professor of cellular and molecular medicine Sourav Ghosh, report that the decision which will be the "plus" and the "minus" end in a newborn nerve cell is made by a long and a short version of the same signaling molecule.
Nerve cells--or neurons--differ from many other cells by their highly asymmetric shape: vaguely resembling a tree, a neuron has one long, trunk-like extension ending in a tuft of root-like bristles. This is called the axon. From the opposite end of the cell body, branch-like structures known as dendrites sprout. By connecting the "branches" of their dendrites to the "root tips" of other neurons' axons, nerve cells form networks, which can be as simple as the few connections involved in the knee-jerk reflex or as complex as those in the human brain.
"We show that wiring a neuronal circuit is much more complex than previously thought," says Ghosh. 'The process has a built-in robustness that explicitly defines which part of the cell is 'positive' and which is 'negative.' How the various brain regions are wired is the basis of emotion, memory, and all cognitive functions. Establishing neuronal polarity in single neurons is absolutely essential for neuronal circuits to form.
"If we understand this mechanism, we could think about methods to spur new axons after the original ones were severed in a traumatic spinal cord injury, for example."
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||The Brain|
|Publication:||USA Today (Magazine)|
|Article Type:||Brief article|
|Date:||Jun 1, 2014|
|Previous Article:||Dried-out leaf hints of global warming.|
|Next Article:||Expanded Franklin Institute opens.|