Biting intentions modulate digastric reflex responses to sudden unloading of the jaw
2014 (English)In: Journal of Neurophysiology, ISSN 0022-3077, E-ISSN 1522-1598, Vol. 112, no 5, 1067-1073 p.Article in journal (Refereed) Published
Reflex responses in jaw opening muscles can be evoked when a brittle object cracks between the teeth and suddenly unloads the jaw. We hypothesized that this reflex response is flexible and, as such, is modulated according to the instructed goal of biting through an object. Study participants performed two different biting tasks when holding a peanut-half stacked on a chocolate piece between their incisors. In one task, they were asked to split the peanut-half only (single-split task) and, in the other task, they were asked to split both the peanut and the chocolate in one action (double-split task). In both tasks, the peanut split evoked a jaw opening muscle response, quantified from EMG recordings of the digastric muscle in a window 20-60 ms following peanut split. Consistent with our hypothesis, we found that the jaw opening muscle response in the single-split trials was about twice the size of the jaw opening muscle response in the double-split trials. A linear model that predicted the jaw opening muscle response on a single trial basis indicated that task settings played a significant role in this modulation but also that the pre-split digastric muscle activity contributed to the modulation. These findings demonstrate that, like reflex responses to mechanical perturbations in limb muscles, reflex responses in jaw muscles not only show gain-scaling but also are modulated by subject intent.
Place, publisher, year, edition, pages
2014. Vol. 112, no 5, 1067-1073 p.
EMG, jaw-opening reflex, motor control, reflex modulation, trigeminal
IdentifiersURN: urn:nbn:se:umu:diva-89697DOI: 10.1152/jn.00133.2014ISI: 000341687200005PubMedID: 24899675OAI: oai:DiVA.org:umu-89697DiVA: diva2:722960