Palestra: “Memória de Curto Prazo Implícita e Vieses Contextuais; Implicit short-term memory and contextual biases”
The context where we perform an action influences how we perceive and act on a particular stimulus. One known effect of how context affects behavior is previous trial effect. This effect have been reported from perceptual to motor domains in human behavior. For example, the speed from previously experienced moving targets bias interceptive movements on current trial. The precise mechanism underlying the previous trial effect is still under debate. In this seminar, I will present results from an experiment wherein we tested the hypothesis that previous encounters with moving targets leave a trace of the information experienced, i.e. an implicit short-term memory mechanism. This information, in turn, could be stored in either premotor or visual areas associated with an interceptive task. In addition, if previous trial effect is indeed caused by lingering activity in regions that processed information about the stimulus in the previous trial, it is reasonable to propose that this short-term memory mechanism would rely on normal functioning of these regions between trials. To test this hypothesis, we had participants (n = 20) perform a coincident timing task and applied rTMS in the inter-trial interval to disrupt the activity in right hV5+ and left dorsal premotor cortex. Trial speed was counterbalanced in a way that allowed every speed to be equally often preceded by all speeds. As expected, participants presented a bias towards the speed of previous trial when intercepting moving targets without receiving rTMS pulses. On the other hand, when disrupting dorsal premotor cortex with rTMS, temporal bias caused by previous trial speed decreased in comparison to Vertex stimulation. When applying rTMS over hV5+, however, temporal bias decreased only mildly, and, although not significantly different from Vertex stimulation, it was significantly different from performing the task without rTMS stimulation.
These results are causal evidence that previous trial effect depends on left dorsal premotor cortex — but only weakly on right hV5+ — proper function during inter-trial interval in a visuomotor integration task with moving objects. This suggests that an implicit short-term memory mechanism keeps information from one trial to the next, and that information — motor or visual — is blended with current trial information and bias behavior.
At the end of the seminar, I will argue that the results from the current study can be explained by a Bayesian Ideal Observer model, that in turn presents testable predictions for future experiments.
Dr. Raymundo Machado de Azevedo Neto (NeuroMat-IME-USP)
Bacharel em Esporte pela Universidade de São Paulo, concluiu mestrado pelo Departamento de Biodinâmica do Movimento do Corpo Humano na Escola de Educação Física e Esporte da Universidade de São Paulo (bolsista CAPES).
Doutor pelo laboratório Neuroimagem Funcional (NIF-LIM44), no Departamento de Radiologia da Faculdade de Medicina da Universidade de São Paulo (Bolsista CAPES). Realizou doutorado sanduíche na Universität Tübingen e Max-Planck Institute for Biological Cybernetics, Alemanha (Bolsista CAPES PDSE).
Atualmente é pesquisador Pós-Doutorando no CEPID Neuromatemática (bolsista FAPESP), no Instituto de Matemática e Estatística da Universidade de São Paulo, tendo como principais interesses de pesquisa a integração visuomotora, efeito da expectativa, memória de curto prazo implícita, aprendizado estatístico implícito, ressonância magnética funcional, estimulação magnética transcraniana, e modelagem matemática e computactional da cognição e comportamento.
A participação é livre, gratuita e não exige conhecimento prévio. Venha conhecer e ampliar seus horizontes!
Quando: 14/11/2018 (Quarta-feira)
Onde: Auditório 5, Bloco Beta, SBC
Horário: 12:50 às 14:00
Colabore: divulgue entre potenciais interessados.