How do temperature robust neural networks in HVC encode for Birdsong timing features?

Experiments and computational studies propose that a feed-forward network of excitatory neurons localized within the premotor nucleus HVC (proper name) encodes for the timing features of birdsong. Focal cooling of HVC in zebra finches leads to an increase in song duration. A Q10 value quantifies the effect of a 10-degree temperature change on biological processes, with a low Q10 indicating temperature robustness. Conformation changes that govern ion channel dynamics in neurons have a Q10 > 2, while the focal cooling studies reported the song Q10 to be ~ 1.3. This raised a question against HVC's role towards encoding song timing. We resolve this by computationally investigating the temperature robustness of HVC network dynamics. Our results demonstrate that neural response is temperature robust, due to strong synaptic inputs and the low Q10 of ionic and synaptic conductance (~ 1.3). These processes are governed by diffusion instead of conformation changes. Moreover, axonal conduction between neurons has a Q10 ~ 1.3, and plays a major role towards temperature robust spike propagation along the network. We also investigate the role of the inhibitory interneuron activity in HVC towards temperature robust network dynamics and discuss possible directions towards experimental research that could help further elucidate HVC's role towards encoding song timing.