Read how Biau and colleagues manipulated audio-visual asynchrony detection and their results that read like this:
‘Results confirm (i) that participants accurately detected audio-visual asynchrony, and (ii) increased delta power in the left motor cortex in response to audio-visual asynchrony. The difference of delta power between asynchronous and synchronous conditions predicted behavioural performance, and (iii) decreased delta-beta coupling in the left motor cortex when listeners could not accurately map visual and auditory prosodies. Finally, both behavioural and neurophysiological evidence was altered when a speaker’s face was degraded by a visual mask.’
Those results suggest that asynchrony detection of audio-visual stimuli in speech is supported by left motor delta oscillations!
Read more here: https://doi.org/10.1523/JNEUROSCI.2965-20.2022