Consideration of Bulbar and Suprabulbar Afferent Influences Upon Speech Motor Coordination and Programming

Abbs, James H.; Cole, Kelly J.

doi:10.1016/b978-0-08-028892-5.50019-0

Cited by 24 publications

(9 citation statements)

References 131 publications

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“…(Although the contractions of the 001 muscle were not performed with the same control over the generated force, it is reasonable to compare the measures of synchronization in a qualitative manner.) It is generally agreed that the 001 does not contain spindles (Abbs and Cole 1982;Bruesch 1944), and Renshaw feedback has not been reported in this muscle. It is true that weak reflexes have been observed in response to mechanical excitation; however, it has been suggested that they are primarily nociceptive in nature (Abbs and Cole 1982), whereas the FDI muscle is known to have an average density of spindles comparable with other muscles of the upper limb (Peck et al 1984).…”

Section: Mechanisms Of Synchronizationmentioning

confidence: 82%

“…It is generally agreed that the 001 does not contain spindles (Abbs and Cole 1982;Bruesch 1944), and Renshaw feedback has not been reported in this muscle. It is true that weak reflexes have been observed in response to mechanical excitation; however, it has been suggested that they are primarily nociceptive in nature (Abbs and Cole 1982), whereas the FDI muscle is known to have an average density of spindles comparable with other muscles of the upper limb (Peck et al 1984). Also, recent work by Rossi and Mazzocchio ( 199 1) indicates that the more distal muscles, such as the intrinsic muscles of the foot and in the FDI (A. Rossi, personal communication), do not exhibit recurrent inhibition.…”

Section: Mechanisms Of Synchronizationmentioning

confidence: 82%

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Synchronization of motor-unit firings in several human muscles

Luca

Roy²,

Erim³

1993

Journal of Neurophysiology

125

105

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1. Synchronization of concurrently active motor-unit firings was studied in six human muscles performing isometric constant-force contractions at 30% of the maximal level. The myoelectric signal was detected with a quadrifilar needle electrode and was decomposed into its constituent motor-unit action-potential trains with the Precision Decomposition technique, whose accuracy has been proven previously. 2. Synchronization was considered as the tendency of two motor units to fire at fixed time intervals with respect to each other more often than would be expected if the motor units fired independently. A rigorous statistical technique was used to measure the presence of peaks in the cross-interval histogram of pairs of motor-unit action-potential trains. The location of the center of peak as well as their width and amplitude were measured. A synch index was developed to measure the percentage of firings that were synchronized. The percentage of concurrently active motor-unit pairs that contained synchronized firings was measured. 3. Synchronization of motor-unit firings was observed to occur in two modalities. The short-term modality was seen as a peak in the cross-interval histogram centered about zero-time delay (0.5 +/- 2.9 ms, mean +/- SD) and with an average width of 4.5 +/- 2.5 ms. The long-term modality was seen as a peak centered at latencies ranging from 8 to 76 ms. On the average, the peaks of the long-term synchronization were 36% lower but had approximately the same width as the peaks for the short-term synchronization. Short-term synchronization was seen in 60% of the motor-unit paris, whereas long-term synchronization was seen in 10% of the pairs. 4. Short-term synchronization occurred in bursts of consecutive firings, ranging in number from 1 to 10, with 91% of all synchronized firing occurring in groups of 1 or 2; and the bursts of discharges appeared at sporadic times during the contraction. 5. The amount of synchronization in motor-unit pairs was found to be low. In the six muscles that were tested, an average of 8.0% of all the firings were short-term synchronized, and an average of 1.0% were long-term synchronized. The synch index was statistically indistinguishable (P = 0.07-0.89) among the different muscles and among 9 of the 11 subjects tested. 6. Sixty percent of concurrently active motor-unit pairs displayed short-term synchronization, 10% of the pairs displayed long-term synchronization, and 8% displayed both modalities.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Mechanisms Of Synchronizationmentioning

confidence: 82%

Section: Mechanisms Of Synchronizationmentioning

confidence: 82%

Synchronization of motor-unit firings in several human muscles

Luca

Roy²,

Erim³

1993

Journal of Neurophysiology

125

105

View full text Add to dashboard Cite

show abstract

“…Superficial mechanoreceptive sensory input, for example, appears to be essential in the control of orofacial movements during human speech [Abbs and Cole, 1982] and in a trained tongue protrusion task in macaques [Murray and Sessle, 1992b, c;Lin et al, 1994a, b]. Thus, the relative expansion of layer III might subserve improved coordination and refinement of orofacial movements related to skilled movements in great apes and humans such as volitional facial expressions, feeding adaptations, and human speech.…”

Section: Variation Between the Catarrhine Familiesmentioning

confidence: 99%

Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

et al. 2004

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Social life in anthropoid primates is mediated by interindividual communication, involving movements of the orofacial muscles for the production of vocalization and gestural expression. Although phylogenetic diversity has been reported in the auditory and visual communication systems of primates, little is known about the comparative neuroanatomy that subserves orofacial movement. The current study reports results from quantitative image analysis of the region corresponding to orofacial representation of primary motor cortex (Brodmann’s area 4) in several catarrhine primate species (Macaca fascicularis, Papio anubis, Pongo pygmaeus, Gorilla gorilla, Pan troglodytes, and Homo sapiens) using the Grey Level Index method. This cortical region has been implicated in the execution of skilled motor activities such as voluntary facial expression and human speech. Density profiles of the laminar distribution of Nissl-stained neuronal somata were acquired from high-resolution images to quantify cytoarchitectural patterns. Despite general similarity in these profiles across catarrhines, multivariate analysis showed that cytoarchitectural patterns of individuals were more similar within-species versus between-species. Compared to Old World monkeys, the orofacial representation of area 4 in great apes and humans was characterized by an increased relative thickness of layer III and overall lower cell volume densities, providing more neuropil space for interconnections. These phylogenetic differences in microstructure might provide an anatomical substrate for the evolution of greater volitional fine motor control of facial expressions in great apes and humans.

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“…The role of bulbar reflexes in the execution of complex movements, including speech, has been discussed in detail without resolution. Abbs and Cole (1982) suggested that orofacial reflexes supporting vegetative functions are incompatible with the motor programs necessary for speech, such that these reflexes must be suppressed during speech production. However, subsequent studies have shown that lip muscle responses to mechanical stimulation can be elicited during speech production and that the amplitude of these responses is not reduced (Smith, Moore, McFarland, & Weber, 1985).…”

mentioning

confidence: 99%

Respiratory Sinus Arrhythmia During Speech Production

Reilly

Moore

2003

J Speech Lang Hear Res

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The amplitude of the respiratory sinus arrhythmia (RSA) was investigated during a reading aloud task to determine whether alterations in respiratory control during speech production affect the amplitude of RSA. Changes in RSA amplitude associated with speech were evaluated by comparing RSA amplitudes during reading aloud with those obtained during rest breathing. A third condition, silent reading, was included to control for potentially confounding effects of cardiovascular responses to cognitive processes involved in the process of reading. Calibrated respiratory kinematics, electrocardiograms (ECGs), and speech audio signals were recorded from 18 adults (9 men, 9 women) during 5-min trials of each condition. The results indicated that the increases in respiratory duration, lung volume, and inspiratory velocity associated with reading aloud were accompanied by similar increases in the amplitude of RSA. This finding provides support for the premise that sensorimotor pathways mediating metabolic respiration are actively modulated during speech production.

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Consideration of Bulbar and Suprabulbar Afferent Influences Upon Speech Motor Coordination and Programming

Cited by 24 publications

References 131 publications

Synchronization of motor-unit firings in several human muscles

Synchronization of motor-unit firings in several human muscles

Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

Respiratory Sinus Arrhythmia During Speech Production

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