Excitability of hand motor areas during articulation of syllables.
It is known that articulating different syllables is linked to different grasp actions, e.g. [ti] is linked to precision grip, and [kɑ] to power grip. The aim of the present study was to test whether articulating or hearing these syllables would result in an increased activity in the representation of hand muscles involved in these two actions in a muscle-specific manner. To this end, we used transcranial magnetic stimulation (TMS) to investigate changes in the excitability of the left primary motor cortex (M1) innervating hand muscles while participants articulated or listened to meaningless syllables, listened to a metronome, or observed a fixation cross. The motor-evoked potentials of two hand muscles associated with either a precision or power grip exhibited significantly greater amplitudes during articulation than in passive listening, metronome, and fixation cross conditions. Moreover, these muscles exhibited similar patterns of excitability during articulation regardless of which syllable was articulated. The increased excitability of the left M1 hand area during articulation, but not during perception of the syllables, might be due to the cortico-cortical interaction between the motor representations of oral organs with the hand area.
['Komeilipoor|Naeem|N|', 'Tiainen|Mikko|M|', 'Tiippana|Kaisa|K|', 'Vainio|Martti|M|', 'Vainio|Lari|L|']
D000328:Adult D019054:Evoked Potentials, Motor D005260:Female D006225:Hand D006801:Humans D008297:Male D009044:Motor Cortex D018482:Muscle, Skeletal D013067:Speech Perception D050781:Transcranial Magnetic Stimulation D014705:Verbal Behavior
Articulation Transcranial magnetic stimulation Motor cortex excitability Syllable perception