Muscular effort increases hand-blink reflex magnitude

Publication date: Available online 5 December 2018Source: Neuroscience LettersAuthor(s): RJ Bufacchi, S Ponticelli, G Novembre, M Kilintari, Y Guo, GD IannettiAbstractDefensive motor responses elicited by sudden environmental stimuli are finely modulated by their behavioural relevance to maximise the organism’s survival. One such response, the blink reflex evoked by intense stimulation of the median nerve (Hand-Blink Reflex; HBR), has been extensively used to derive fine-grained maps of defensive peripersonal space. However, as other subcortical reflexes, the HBR is also modulated by lower-level factors that do not bear direct relevance to defence, thus posing methodological and interpretive problems. Here, we tested whether the HBR magnitude is affected by the muscular effort caused by holding the hand in certain postures. We found that HBR magnitude increases with muscular effort, an effect most likely mediated by the increased corticospinal drive. However, we found strong evidence that this effect is substantially smaller than the well-known effect of eye-hand proximity on HBR magnitude. Nonetheless, care should be taken in future experiments to avoid erroneous interpretations of the effects of muscular effort as indicators of behaviour relevance.
Source: Neuroscience Letters - Category: Neuroscience Source Type: research