Novel spatiotemporal perturbations in a finger-tapping task

LOPEZ SABRINA LAURA; LAJE, RODRIGO

Córdoba

Congreso; XXXIII Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias; 2018

Sociedad Argentina de Investigación en Neurociencias

Finger tapping is a paradigmatic task to study sensorimotor synchronization. In this task, the subject must tap with his finger in synchrony with a periodic sequence of brief tones, as in keeping pace with the music. Temporal differences (asynchronies) between each response and the corresponding stimulus are recorded. A usual experimental manipulation is the unexpected shortening or lengthening of the sequence?s period (tempo change). In model interpretation, this is a limitation because this type of perturbation generates a change in the parameter (period of the sequence), but also in the variable (asynchrony) as a forced error occurs. In this study, we make a novel perturbation: we generate a temporal perturbation without changing the tempo. To achieve this we use a servo to shift the contact point either upwards or downwards, leading to an earlier- or later-than-intended finger tap, respectively. In this way, we uncouple the effects of the traditional temporal perturbations as the variable of interest (asynchrony) is manipulated without changing the parameter (tempo). Our results reproduce nonlinear effects already reported and suggest that the origin of the asynchrony (forced by tempo change or by contact point shift) does not influence the subsequent resynchronization. Both types of asynchronies are processed by the same error mechanism.