Stochastic dynamical systems model of vocal turn-taking and its development in marmoset monkeys

The system of taking turns during vocal exchanges is fundamental to the communication of several animal species, yet their developmental origins and neural mechanisms remain elusive. Marmoset monkeys readily exchange vocalization when in acoustic contact with conspecifics. Moreover, their turn-taking capacity improves during development, decreasing the amount of overlap. We, therefore, used marmosets to explore the neural and developmental basis of turn-taking. To do that, we developed a stochastic dynamical systems model of marmoset monkeys based on the interactions among three neural structures ('drive,' 'motor,' and 'auditory') with feedback connectivity inspired by published physiological and anatomical data. The distinctive feature of our model is that it allows us to measure the amount of noise in the (cognitive) drive separately from the noise in the (sensory) auditory system, where the noise plays a key role as a source of variability in the system. Fitting the model to empirical data, we found that the noise level in the auditory sensory system decreases during development, becoming noiseless after one-month postnatal day. This noiseless period matches the timing of the significant improvement in marmoset capacity to avoid overlapping calls, suggesting that the increased signal-to-noise ratio in the auditory sensory system, but not in the cognitive drive, is a major source for early development of turn-taking capacity.

Short Bio

Daniel Y Takahashi is an assistant professor at the Brain Institute (ICe), Federal University of Rio Grande do Norte, Brazil. He has a Ph.D. in Bioinformatics from the University of São Paulo, Brazil. He develops models that try to explain the evolutionary and developmental origins of complex animal behaviors. Lab website https://neuro.ufrn.br/ethogenesis/