Multiple network properties overcome random connectivity to enable stereotypic sensory responses.

Mittal AM, Gupta D, Singh A, Lin AC, Gupta N.

Nature communications. 2020 Feb 24;11(1):1-5.

Do different individuals perceive the same thing the same way—this seemingly intractable question continues to remain largely unresolved. Prof. Nitin Gupta and team set out to look for answers using the insect olfactory system.
It is known that connections between neuronal populations may be genetically hardwired, or these could be random. For instance, in the insect olfactory system, projection neurons of the antennal lobe connect randomly to Kenyon cells of the mushroom body. Intriguingly, while the odor responses of the projection neurons are stereotyped across individuals, the responses of the Kenyon cells are variable. Despite this, strikingly, downstream of Kenyon cells, mushroom body output neurons once again display stereotypy in their responses.

Prof Nitin Gupta and team, uncovered that stereotypy in the output neurons is enabled by the convergence of inputs from many Kenyon cells onto a single output neuron, and did not require learning. The stereotypy thus emerges in the total response of the Kenyon cell population using multiple odor-specific features of the projection neuron responses, benefits from the nonlinearity in the transfer function, depends on the convergence:randomness ratio, and is constrained by sparseness.