How neurons develop their vast networks of axons and dendrites with apparently accurate targeting to generate a functioning brain remains a core question in neuroscience. Although some of the interconnections might be partially "random" with the resulting complex network still managing to generate meaningful neural function, it still seems that the network connects in a directed way. How neurons know with whom to connect remains mostly unclear.

Image from Salk Institute for Biological Studies

Using genetically-modified neurons from a mouse, the O'Leary research group from the Salk Institute for Biological Studies found a surprising additional function of a well-known protein called "p75." Also involved in the regulation of keeping a neuron alive, it has now been observed to affect and direct axon growth.

And the function is rather interesting: the protein apparently does not act to attract an axon to follow a certain path... ("come follow me to the promised land!"), but rather it repulses the growth cone to head in another direction... ("yer git on outta here!").

The important aspect of this research is leading to a complete understanding of neuron network growth and development, in particular the understanding of what controls how and where the network connections develop. If we know what are the biological controls, then we can in turn control or influence these factors to guide neurons implanted on a neurotechnological device to connect in specific ways that might be needed for a particular application.

Read more about this interesting work, and think about how this p75 protein might be involved in your next neurotech implant....