Poster C94, Sunday, March 25, 1:00-3:00 pm, Exhibit Hall C
Dynamic shaping of the defensive peripersonal space through kinesthetic illusion
Monica Biggio1, Ambra Bisio1, Piero Ruggeri1, Marco Bove1; 1University of Genoa, Italy
The Hand Blink Reflex (HBR) is a subcortical defensive response, elicited by the electrical stimulation of the median nerve. HBR responses dramatically increased when the stimulated hand moves inside the defensive peripersonal-space (DPPS) of the face, no matter what kind of movement (voluntary, passive or imagined). We aim to investigate whether the kinesthetic illusion of movement evoked by proprioceptive stimulation could modulate the HBR responses like other dynamic conditions. In 8 healthy subjects showing reproducible HBR responses we evoked the illusion of movement by vibrating biceps and triceps of the right arm to induce, respectively, the sensation to move the forearm down - far from the face, and up - towards the face. Electromyographic activity was recorded from the orbicularis oculi muscles while the HBR response was elicited in three starting hand positions, depending on the distance of the hand from the face (far, intermediate and near positions). Results showed that HBR responses during both kinesthetic illusion and voluntary movement conditions decreased with respect to static condition, showing an effect of sensory attenuation. However there were no significant differences between the down-moving illusion when the stimulation occurred inside the DPPS and the up-moving illusion with the arm standing in far position. Our data provide information about the neural mechanism that potentially modulates HBR: associative areas responsible for the illusory movement sensation might exert a top-down control on subcortical circuitry of HBR modulation.
Topic Area: PERCEPTION & ACTION: Motor control