Interaction in planning vocalizations and grasping

Peer reviewe

Systematic Influence of Perceived Grasp Shape on Speech Production

Previous research has shown that precision and power grip performance is consistently influenced by simultaneous articulation. For example, power grip responses are performed relatively fast with the open-back vowel [a], whereas precision grip responses are performed relatively fast with the close-front vowel [i]. In the present study, the participants were presented with a picture of a hand shaped to the precision or power grip. They were required to pronounce speech sounds according to the front/above perspective of the hand. The results showed that not only the grip performance is affected by simultaneously pronouncing the speech sound but also the production of speech sound can be affected by viewing an image of a grip. The precision grip stimulus triggered relatively rapid production of the front-close vowel [i]. In contrast, the effect related to the power grip stimulus was mostly linked to the vertical dimension of the pronounced vowel since this stimulus triggered relatively rapid production of the back-open vowel [a] and back-mid-open vowel [o] while production of the back-close vowel [u] was not influenced by it. The fact that production of the dorsal consonant [k] or coronal consonant [t] were not influenced by these stimuli suggests that the effect was not associated with a relative front-back tongue shape of the articulation in the absence of changes in any vertical articulatory components. These findings provide evidence for an intimate interaction between certain articulatory gestures and grip types, suggesting that an overlapping visuomotor network operates for planning articulatory gestures and grasp actions.Peer reviewe

(Dis‑)Harmony in movement: effects of musical dissonance on movement timing and form

While the origins of consonance and dissonance in terms of acoustics, psychoacoustics and physiology have been debated for centuries, their plausible effects on movement synchronization have largely been ignored. The present study aimed to address this by investigating whether, and if so how, consonant/dissonant pitch intervals affect the spatiotemporal properties of regular reciprocal aiming movements. We compared movements synchronized either to consonant or to dissonant sounds and showed that they were differentially influenced by the degree of consonance of the sound presented. Interestingly, the difference was present after the sound stimulus was removed. In this case, the performance measured after consonant sound exposure was found to be more stable and accurate, with a higher percentage of information/movement coupling (tau coupling) and a higher degree of movement circularity when compared to performance measured after the exposure to dissonant sounds. We infer that the neural resonance representing consonant tones leads to finer perception/action coupling which in turn may help explain the prevailing preference for these types of tones

Preparation and execution of teeth clenching and foot muscle contraction influence on corticospinal hand-muscle excitability

Contraction of a muscle modulates not only the corticospinal excitability (CSE) of the contracting muscle but also that of different muscles. We investigated to what extent the CSE of a hand muscle is modulated during preparation and execution of teeth clenching and ipsilateral foot dorsiflexion either separately or in combination. Hand-muscle CSE was estimated based on motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and recorded from the first dorsal interosseous (FDI) muscle. We found higher excitability during both preparation and execution of all the motor tasks than during mere observation of a fixation cross. As expected, the excitability was greater during the execution phase than the preparation one. Furthermore, both execution and preparation of combined motor tasks led to higher excitability than individual tasks. These results extend our current understanding of the neural interactions underlying simultaneous contraction of muscles in different body parts.Peer reviewe

Selective Influences of Precision and Power Grips on Speech Categorization

Peer reviewe

Involvement of superior temporal areas in audiovisual and audiomotor speech integration

Perception of speech sounds is affected by observing facial motion. Incongruence between speech sounds and watching somebody articulating may influence the perception of auditory syllable, referred to as the McGurk effect. We tested the degree to which silent articulation of a syllable also affects speech perception and searched for its neural correlates. Listeners were instructed to identify the auditory syllables /pa/ and /ta/ while silently articulating congruent/incongruent syllables or observing videos of a speaker's face articulating them. As a baseline, we included an auditory-only condition without competing visual or sensorimotor input. As expected, perception of sounds degraded when incongruent syllables were observed, and also when they were silently articulated, albeit to lesser extent. This degrading was accompanied by significant amplitude modulations in the beta frequency band in right superior temporal areas. In these areas, the event-related beta activity during congruent conditions was phase-locked to responses evoked during the auditory-only condition. We conclude that proper temporal alignment of different input streams in right superior temporal areas is mandatory for both audiovisual and audiomotor speech integration

Enhanced corticobulbar excitability in chronic smokers during visual exposure to cigarette smoking cues

Background: Neuroimaging studies of chronic smokers report altered activity of several neural regions involved in the processing of rewarding outcomes. Neuroanatomical evidence suggests that these regions are directly connected to the tongue muscle through the corticobulbar pathways. Accordingly, we examined whether corticobulbar excitability might be considered a somatic marker for nicotine craving. Methods: We compared motor-evoked potential (MEP) amplitudes recorded from the tongue and the extensor carpi radialis (control muscle) of chronic smokers under drug withdrawal and intake conditions as well as a nonsmoker group. All participants were tested during passive exposure to pictures showing a smoking cue or a meaningless stimulus. In the intake condition, chronic smokers were asked to smoke a real cigarette (CSn: group 1) or a placebo (CSp: group 2). Results: Results show that MEP amplitudes recorded from the tongues of participants in the CSn and CSp groups under the withdrawal condition were selectively enhanced during exposure to a smoking cue. However, this effect on tongue MEP amplitudes disappeared in the intake condition for both the CSn and CSp groups. Limitations: Limitations include the fact that the study was conducted in 2 different laboratories, the small sample size, the absence of data on chronic smoker craving strength and the different tastes of the real and placebo cigarettes. Conclusion: These results suggest that, in chronic smokers, tongue muscle MEP amplitudes are sensitive to neural processes active under the physiological status of nicotine craving. This finding implicates a possible functional link between neural excitability of the corticobulbar pathway and the reward system in chronic smokers

Subjective and Normative Mean Arousal Rating Scores on a Scale Ranging From 1 (Very Calm) to 9 (Very Excited).

<p>Subjective and Normative Mean Arousal Rating Scores on a Scale Ranging From 1 (Very Calm) to 9 (Very Excited).</p

Enhanced corticobulbar excitability in chronic smokers during visual exposure to cigarette smoking cues.

BACKGROUND: Neuroimaging studies of chronic smokers report altered activity of several neural regions involved in the processing of rewarding outcomes. Neuroanatomical evidence suggests that these regions are directly connected to the tongue muscle through the corticobulbar pathways. Accordingly, we examined whether corticobulbar excitability might be considered a somatic marker for nicotine craving. METHODS: We compared motor-evoked potential (MEP) amplitudes recorded from the tongue and the extensor carpi radialis (control muscle) of chronic smokers under drug withdrawal and intake conditions as well as a nonsmoker group. All participants were tested during passive exposure to pictures showing a smoking cue or a meaningless stimulus. In the intake condition, chronic smokers were asked to smoke a real cigarette (CSn: group 1) or a placebo (CSp: group 2). RESULTS: Results show that MEP amplitudes recorded from the tongues of participants in the CSn and CSp groups under the withdrawal condition were selectively enhanced during exposure to a smoking cue. However, this effect on tongue MEP amplitudes disappeared in the intake condition for both the CSn and CSp groups. LIMITATIONS: Limitations include the fact that the study was conducted in 2 different laboratories, the small sample size, the absence of data on chronic smoker craving strength and the different tastes of the real and placebo cigarettes. CONCLUSION: These results suggest that, in chronic smokers, tongue muscle MEP amplitudes are sensitive to neural processes active under the physiological status of nicotine craving. This finding implicates a possible functional link between neural excitability of the corticobulbar pathway and the reward system in chronic smokers

Subjective and Normative Mean Valence Rating Scores on a Scale Ranging From 1 (Very Pleasant) to 9 (Very Unpleasant).

<p>Subjective and Normative Mean Valence Rating Scores on a Scale Ranging From 1 (Very Pleasant) to 9 (Very Unpleasant).</p