Poster B94, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Cognitive tuning of the defensive peripersonal space is influenced by postural adjustment ability
Marco Bove1, Monica Biggio1, Ambra Bisio1, Piero Ruggeri1; 1University of Genoa, Italy
The hand blink reflex (HBR) is a subcortical defensive response, known to dramatically increase when the stimulated hand is statically positioned inside the defensive peripersonal space (DPPS) of the face. DPPS has a crucial role for survival, and its modulation is fundamental when we interact with the surrounding environment. A fine cortical tuning of HBR was observed when a thin wooden screen was placed between the participants' face and their hand. Thus, the screen reduces the extension of the DPPS so that the hand is never inside the defensive peripersonal space of the face. We hypothesized that this “screen effect” can automatically manifest as consequence of experience in those athletes who use hands as a shield to protect the face from an external threatening stimulus, as it occurs when boxers assume the guard position. Thirteen boxers and 13 age-matched controls were enrolled. Electromyographic activity was recorded from the orbicularis oculi muscles. HBR response was elicited in three static hand positions from the face: far, intermediate and near positions. HBR enhancement in the near position was present only in the control group, while no significant difference was found in the three positions in the boxer group. Also, the higher years of practice in boxing the higher suppression occurred. These observations suggest that, as a result of sensorimotor experience, the brain can shape the DPPS by evaluating the harm probability through the assessment of the ability to set an accurate defensive postural adjustment able to cope with possible dangerous stimuli.
Topic Area: PERCEPTION & ACTION: Motor control