  We study external, electrical perturbations and their responses in the brain
dynamic network of the \textit{Caenorhabditis elegans} soil worm, given by the
connectome of its large somatic nervous system. Our analysis is inspired by a
realistic experiment where one stimulates externally specific parts of the
brain and studies the persistent neural activity triggered in other cortical
regions. In this work, we perturb groups of neurons that form communities,
identified by the walktrap community detection method, by trains of
stereotypical electrical Poissonian impulses and study the propagation of
neural activity to other communities by measuring the corresponding dynamic
ranges and Steven law exponents. We show that when one perturbs specific
communities, keeping the rest unperturbed, the external stimulations are able
to propagate to some of them but not to all. There are also perturbations that
do not trigger any response. We found that this depends on the initially
perturbed community. Finally, we relate our findings for the former cases with
low neural synchronization, self-criticality and large information flow
capacity, and interpret them as the ability of the brain network to respond to
external perturbations when it works at criticality and its information flow
capacity becomes maximal.
