Sensorimotor integration and faces recognition in a model of altered face sensory information: neurophysiological study in patients with dentofacial deformities

Objective
To explore the excitability and sensory motor integration of the face and masticatory primary motor cortex (M1), and recognition of face expressions in individuals with dentofacial deformities (IDD).
Methods
Short-interval intracortical inhibition (SICI), short-afferent inhibition (SAI) of masticatory and face M1, the blink reflex and face expressions recognition (FER) ability were assessed in 18 healthy subjects (HS) (24.56±1.02 years old) and in 18 IDD (27.36±1.39 years) before and after 1 month from surgery.
Results
In IDD, SICI (p=0.033) and SAI (p=0.008) were significantly reduced in the masticatory, but not face, M1 and the blink reflex was normal. IDD also exhibited deficits in FER before surgery (p=0.033), which was still present after surgery (p=0.015), although improved.
Conclusion
Results evidence that alterations of sensory afferents due to dentofacial deformities modulates sensorimotor integration of masticatory M1, with topographic specificity. The altered sensory information from face not only influences motor inhibitory control but also FER.
Significance
The integration of sensory inputs with motor outputs depends topographically on the type of sensory afferents stimulated as well as on the target muscle and its respective representation area in M1. Afferent information from face also plays a role in FER ability.