A Neural Basis for Contagious Yawning

Abstract

Contagious yawning, in which yawning is triggered involuntarily when we observe another person yawn, is a common form of echophenomena-the automatic imitation of another's words (echolalia) or actions (echopraxia) [1]. The neural basis for echophenomena is unknown; however, it has been proposed that it is linked to disinhibition of the human mirror-neuron system [1-4] and hyper-excitability of cortical motor areas [1]. We investigated the neural basis for contagious yawning using transcranial magnetic stimulation (TMS). Thirty-six adults viewed video clips that showed another individual yawning and, in separate blocks, were instructed to either resist yawning or allow themselves to yawn. Participants were videoed throughout and their yawns or stifled yawns were counted. We used TMS to quantify motor cortical excitability and physiological inhibition for each participant, and these measures were then used to predict the propensity for contagious yawning across participants. We demonstrate that instructions to resist yawning increase the urge to yawn and alter how yawns are expressed (i.e., full versus stifled yawns) but do not alter the individual propensity for contagious yawning. By contrast, TMS measures of cortical excitability and physiological inhibition were significant predictors of contagious yawning and accounted for approximately 50% of the variability in contagious yawning. These data demonstrate that individual variability in the propensity for contagious yawning is determined by cortical excitability and physiological inhibition in the primary motor cortex.

The spectrum of involuntary vocalizations in humans: A video atlas

“…Sniffing, coughing, belching (Video 5A), and hiccup‐related sounds (Video 5B) were also documented in functional neurological disorders . Other physiological involuntary vocalizations are “contagious yawning” or groaning during sexual intercourse …”

Entraining Movement-Related Brain Oscillations to Suppress Tics in Tourette Syndrome

“…To investigate whether delivering rhythmic trains of mu-band (10 Hz) MNS to the right wrist had a significant effect on the occurrence of tics and the experience of the urge-to-tic in TS, we conducted a lengthy series of case studies in which 19 individuals with TS were video recorded while receiving randomly interleaved 1-min periods of MNS versus no stimulation. Throughout this period, participants were required to continuously report their self-estimated urge-to-tic by using a slider device reported previously [17]. Three patients withdrew from the study because they found the MNS uncomfortable, and a further three participants required a reduction in stimulation intensity (80% of threshold) to continue.…”

Infant brain activity in response to yawning using functional near-infrared spectroscopy

“…Contagious yawning is related to the social brain regions such as the STS and the mirror-neuron systems 29 . A recent study showed that the primary motor cortex is the important region for contagious yawning rather than the mirror-neuron systems 30 . Considering the developmental trajectory of yawning, spontaneous yawning is observed even in fetuses 11 .…”