[ABE-L] Seminário UFSCar/ICMC – Sexta 27/11/2015 - 14h00 - no ICMC

[Rafael Izbicki]

Divulgação da palestra desta semana do Seminário do Programa
Interinstitucional de Pós-graduação em Estatística
<http://www.icmc.usp.br/Portal/conteudo/1096/13/interinstitucional-de-pos-graduacao-em-estatistica>
 (PIPGEs ICMC/USP e UFSCar), São Carlos.

*Palestrante:* Daniel Y. Takahashi (Princeton University)

*Título:* Investigating the dynamics of a coupled oscillator model of vocal
turn-taking using a Turing-like test with marmoset monkeys

*Resumo: *Conversation is an integral component of human social
interaction. These are vocal exchanges between two individuals that take
turns with no explicit rules established between them. Given its
importance, it is natural to ask how turn-taking evolves and develops, and
what might be its neural basis. We’ve shown that marmoset monkeys take
turns during natural dyadic vocal exchanges and that the timing of
exchanges is periodically coupled (Takahashi et al., 2013a). Such behavior
likely involves many different neural structures related to both vocal
production and social decision-making. With regard to the latter, we built
a dynamical systems model whereby a stochastic oscillator represents each
marmoset. Each oscillator simulates the interactions among four structures
(‘drive’, ‘motor’ and two ‘auditory’ nodes) with connectivity inspired by
published physiological and anatomical data. A key characteristic of our
model is the presence of a self-reference (i.e., corollary discharge)
circuit whose dynamics distinguish self-produced calls from calls produced
by another individual. We coupled the two oscillators together and fit
their output to the data of real vocally-interacting marmosets. We show
that it generates turn-taking dynamics nearly identical to that seen in
natural marmoset vocal exchanges. [Note: the coupled model also accurately
captures the dynamics of human conversational exchanges.] Using interactive
playbacks, we then validated the model by applying a Turing-like test: does
a dyad consisting of one model oscillator and one real marmoset reproduce
the turn-taking dynamics of two real marmosets? We then tested the role of
self-reference during these vocal interactions by performing the same test
of the model but without the corollary discharge circuit. We show that
understanding the difference in the dynamics of the interaction with and
without self-reference leads to testable hypotheses with regard to the
dynamics of real neural circuits underlying vocal communication. I will
emphasize the statistical and probabilistic aspects of the problem. This is
joint work with Asif A. Ghazanfar.

*Local:* Sala 4111 do ICMC

*Data/Horário:*  Sexta-feira 27/11/2015;  14hs.


--
Rafael Izbicki
Assistant Professor
Department of Statistics
Federal University of São Carlos (UFSCar)
rizbicki.wordpress.com
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