A circular model for song motor control in Serinus canaria

Abstract

Song production in songbirds is controlled by a network of nuclei distributed across several brain regions, which drives respiratory and vocal motor systems to generate sound. We built a model for birdsong production, whose variables are the average activities of different neural populations within these nuclei of the song system. We focus on the predictions of respiratory patterns of song, because these can be easily measured and therefore provide a validation for the model. We test the hypothesis that it is possible to construct a model in which (1) the activity of an expiratory related (ER) neural population fits the observed pressure patterns used by canaries during singing, and (2) a higher forebrain neural population, HVC, is sparsely active, simultaneously with significant motor instances of the pressure patterns. We show that in order to achieve these two requirements, the ER neural population needs to receive two inputs: a direct one, and its copy after being processed by other areas of the song system. The model is capable of reproducing the measured respiratory patterns and makes specific predictions on the timing of HVC activity during their production. These results suggest that vocal production is controlled by a circular network rather than by a simple top-down architecture.

Modeling temperature manipulations in a circular model of birdsong production

“…The values were chosen so that the ER dynamics could be directly compared with the pressure patterns. The rest of the numbers are the same as in Alonso et al [15]. Different families of pressure patterns, as the ones shown in Fig.…”

“…Our starting point was a mathematical representation proposed by Alonso et al [15] that qualitatively describes the mechanisms that generate the different pressure patterns observed during the song of canaries. This vision opposes to a scenario where periodic activity in HVC is enough to generate the vast syllabic repertoire.…”

“…In an alternative hypothesis, the activation of the neuronal nuclei responsible for respiration may not only be due to the activity in the telencephalic area flowing downstream but also to the activation in other regions within the brainstem [15][16][17][18]. This does not mean that the timing signals in HVC do not play a crucial role, but that the system has to be analyzed in an integral fashion.…”

“…[15]. The authors proposed an average description of the activity of each intervening area of the motor pathway, modeling it with a neural additive model.…”

“…This does not mean that the timing signals in HVC do not play a crucial role, but that the system has to be analyzed in an integral fashion. A computational model was developed to represent this proposed architecture in the work of Alonso et al [15]. In this framework, neural populations in the brainstem are connected upstream via the thalamus with HVC, which provides an architecture that gives the model its name: circular model.…”