Connected neurons form neural circuits responsible for specific behaviors and functions. However, little is known about how  neural circuits change in response to experiences.

In research involving the roundworm C. elegans, Leo T.H. Tang, Ph.D., Hannes Buelow, Ph.D., and colleagues have shown for the first time how a neural circuit is rewired during associative learning. Specifically, when roundworms learned to associate a low-salt concentration with food, they developed an asymmetric salt-sensing circuit containing more synapses on the left side of the circuit than the right side. However, roundworms conditioned to associate elevated-salt concentrations with food changed their “left-biased” asymmetric salt-sensing network to favor synapses on the right side.

Interestingly, this rewiring was mediated by an insulin-like peptide. The human genome encodes about 10 different such peptides and brains in vertebrates and invertebrates are known to display asymmetric functions, but mechanisms regulating them are not known. The findings, published August 16 in Current Biology, could shed light on the many neuropsychiatric conditions, such as autism spectrum disorders, characterized by changes in lateralized brain function (i.e., functions specialized to one side of the brain or the other).

Dr. Buelow, the study’s senior and co-corresponding author, is professor in the of genetics and in the Dominick P. Purpura Department of Neuroscience at Einstein. Dr. Tang is also a co-corresponding author and is an associate in the department of genetics.