Sex differences in visual-proprioceptive feedback utilization via focus of attention instructions


The focus of one's attention to internal or external cues (within or outside the body, respectively) has been shown to influence motor learning and performance. Further, attentional cues have been shown to modulate performance within individuals, but also across individuals, particularly between sexes. Insofar, sex differences have often been attributed to differences in sensory-weighting such that males tended to rely more on interoceptive feedback, whereas females tended to rely more on exteroceptive feedback. However, the experimental tasks mainly used visual manipulations, thus failing to elicit differences in proprioceptive feedback (i.e., interoceptive). The current study tested the influence of attention instructions during prismatic adaptation (i.e., visual-proprioceptive mismatch), across sexes. Twenty-four participants (12 females) made reaches to an illuminated target, while donning liquid crystal goggles. Following baseline testing, a neutral, interoceptive (proprioceptive-based), and exteroceptive (visual-based) attentional focus instructions were given to participants, for both a 20-dioptre (11 degree) rightward Fresnel prism block (i.e., adaptation) and a no-prism block (i.e., after-effect). Upper-limb reaches were recorded with a Certus camera. Despite no differences in movement time, time spent prior to peak velocity was significantly longer in the interoceptive focus vs. the neutral condition for both sexes (i.e., greater emphasis on efferent comparisons and/or early proprioceptive feedback use). In addition, with exteroceptive attention instructions, males demonstrated greater endpoint variability in the mediolateral axis than females. Therefore, instructions to attend on interoceptive vs. exteroceptive cues altered motor planning and/or early online control for both sexes, whereas only males exhibited significant differences in reaching trajectories.