The Role of Motor Inhibition During Covert Speech Production

Abstract

Covert speech is accompanied by a subjective multisensory experience with auditory and kinaesthetic components. An influential hypothesis states that these sensory percepts result from a simulation of the corresponding motor action that relies on the same internal models recruited for the control of overt speech. This simulationist view raises the question of how it is possible to imagine speech without executing it. In this perspective, we discuss the possible role(s) played by motor inhibition during covert speech production. We suggest that considering covert speech as an inhibited form of overt speech maps naturally to the purported progressive internalization of overt speech during childhood. We further argue that the role of motor inhibition may differ widely across different forms of covert speech (e.g., condensed vs. expanded covert speech) and that considering this variety helps reconciling seemingly contradictory findings from the neuroimaging literature.

The ‘reading’ brain: Meta-analytic insight into functional activation during reading

“…There is evidence that motor planning and inhibition are coordinated even in the absence of overt speech, although motor inhibition might differ across forms of speech production/reading, potentially explaining contradictory results in neuroimaging studies 80 . In the present work, the direct comparison of overt reading with covert reading tasks, however, reveals a clear dominance of activation in bilateral motor and auditory regions during overt reading.…”