The relationship between cortically induced mandibular movements and lateral pterygoid and digastric muscle EMG activity in the anesthetized guinea pig

Lambert, Richard W.; Goldberg, Louis J.; Chandler, Scott H.

doi:10.1016/0006-8993(85)90507-4

Cited by 8 publications

(14 citation statements)

References 20 publications

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“…These data demonstrate that a given cortex activates neurons within the contralateral lower brain stem that then project to ipsilateral and/ or contralateral jaw-opener motoneurons. Consistent with these data are the observations that the short-latency bilateral DIG EMG responses produced by SPT cortical stimulation are approximately 2 msec longer for the ipsilateral than for the contralateral DIG EMG (Lambert et al, 1985;Lund et al, 1984). This longer delay could be accounted for by a recrossing to the ipsilateral side.…”

Section: Discussionsupporting

confidence: 75%

“…b; Lambert et al, 1985;Lund et al, 1984;see Dubner et al, 1978, or Luschei and Goldberg, 198 1, for review). One question that has not been resolved with respect to RJMs is how this coordination is produced.…”

Section: Discussionmentioning

confidence: 99%

“…Our results indicate the possibility of an independent oscillator(s) within each side of the lower brain stem that is exclusively controlled by the contralateral cortex and that can coordinate DIG motoneurons bilaterally. This apparent redundancy in neuronal oscillators is important when one considers that each cortex initiates not only rhythmical opening and closing activity, but also has the capability of initiating a specific lateral component to the movement sequence (Lambert et al, 1985). Each side of cortex activates a CPG located in the contralateral brain stem, which then alternately facilitates and inhibits the DIG pre-motoneurons located in the parvocellular RF.…”

Section: Discussionmentioning

confidence: 99%

“…1, A, C), while repetitive stimulation of the same cortical site at 40 Hz produces RJMs of 3-5 Hz concomitant with bilaterally synchronous EMG activity in both DIG muscles ( Fig. 2, A, B) (Lambert et al, 1985). To determine the importance of the continuity of both sides of the lower brain stem on both the bilateral DIG responses produced by SPT stimulation of the cortex and the ability of the cortex to initiate…”

Section: Midline Transectionsmentioning

confidence: 99%

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The effects of brain stem transections on the neuronal networks responsible for rhythmical jaw muscle activity in the guinea pig

Chandler¹,

Tal²

1986

J. Neurosci.

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The purpose of this study was to determine the critical areas of brain stem necessary for the production of cortically induced rhythmical jaw muscle activity (RJMs) in the anesthetized guinea pig. It was found that longitudinal midline transections of the lower brain stem starting at the obex and extending to the rostral third of the inferior olivary nucleus (IO) were able to abolish rhythmical EMG activity in the jaw-opener muscle (digastric) on the same side (ipsilateral) as the cortical stimulus. Under these conditions, rhythmical activity in the contralateral digastric (DIG) EMG was not affected. Midline transections extending from the rostral superior colliculus to 500 microns rostral to the trigeminal motor nucleus had no effect on cortically evoked bilateral DIG rhythmical EMG activity. Serial transverse hemisections of the left side of the medulla, starting at the obex and extending to the rostral third of the IO, reduced the amplitude of the left DIG EMG without producing significant effects in the cycle characteristics [cycle duration (CD) or burst duration (BD)] of that muscle during stimulation of the contralateral (right) cortex. Hemisections more rostral to the IO completely abolished bilateral rhythmical DIG activity induced by stimulation of the cortex on the side opposite to the transection (right cortex). Under these conditions, stimulation of the cortex on the side ipsilateral to the left hemisection (left cortex) initiated rhythmical EMG activity with normal cycle characteristics in only the contralateral (right) DIG muscle. Transverse hemisections as little as 500 microns rostral to the trigeminal motor nucleus (Mot V), which spared the pyramidal tract, had no effect on RJMs induced by stimulation of either cortex. These data suggest that each ipsilateral cortex initiates activity in neuronal oscillatory networks located exclusively in the contralateral brain stem; bilateral rhythmical DIG activity is produced by neurons in the contralateral brain stem; each side of the lower brain stem is capable of producing rhythmical DIG activity independent of the integrity of the other side; and the location of the neuronal oscillators responsible for RJMs is between the rostral IO and the trigeminal motor nucleus.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Midline Transectionsmentioning

confidence: 99%

See 2 more Smart Citations

The effects of brain stem transections on the neuronal networks responsible for rhythmical jaw muscle activity in the guinea pig

Chandler¹,

Tal²

1986

J. Neurosci.

View full text Add to dashboard Cite

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“…These responses could have masked a facilitatory effect on the circuits controlling RIMS. In previous studies we argued that a central pattern-generating (CPG) network(s), activated by masticatory cortex, phasically modulates the excitability of DIG premotoneurons, which themselves are activated directly by masticatory cortex, to produce rhythmical jaw opening during repetitive cortical stimulation (Chandler and Goldberg, 1982;Chandler et al, 1985a;Lambert et al, 1985). Furthermore, it was suggested that these premotoneurons are not a component of the CPG network(s) but merely output neurons of that network(s) (Chandler and Goldberg, 1982;Chandler et al, 1985a).…”

Section: Discussionmentioning

confidence: 99%

Brain-stem perturbations during cortically evoked rhythmical jaw movements: effects of activation of brain-stem loci on jaw muscle cycle characteristics

Chandler¹,

Tal²

1987

J. Neurosci.

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The purpose of the present study was to further elucidate with the use of microstimulation techniques the influences of rostral pons and midbrain loci on the neuronal networks responsible for cortically induced rhythmical jaw movement (RJM) activity in the anesthetized guinea pig and to establish if these rostral brain-stem loci are capable of modulating the timing as well as the amplitude of rhythmical digastric (DIG) EMG activity. It was found that repetitive electrical stimulation of widespread areas of the rostral pons and mid-brain produced suppression of ongoing cortically induced rhythmical EMG activity. Prior to complete EMG suppression there was a reduction in amplitude of the DIG EMG and an increase in cycle duration. Repetitive stimulation of these suppressive loci also produced a reduction in the amplitude of the short-latency DIG EMG response produced by short pulse train stimulation of the masticatory cortex. This indicates that part of the suppression of cortically induced rhythmical EMG activity was due to a reduction in excitability of the polysynaptic short-latency pathway from cortex to DIG motoneurons. Short pulse train stimulation of these brain-stem suppressive loci during various phases of the rhythmical DIG cycle produced a phase-dependent increase in duration of the ongoing perturbed cycle. The cycles following the stimulus perturbation did not show any compensatory shortening in their durations suggesting that the stimulus produced a true resetting of the cycle. These data suggest that the brain-stem loci that produce suppression of RJMs evoked by repetitive cortical stimulation can affect the excitability of the central circuits responsible for cycle oscillation and timing as well as the excitability of the polysynaptic short-latency corticotrigeminal pathway to DIG motoneurons.

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Functional mapping of the motor cortex of the white mouse by a microstimulation method

Pronichev¹,

Lenkov²

1998

Neurosci Behav Physiol

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Studies on 33 anesthetized white mice were used to determine the motor representation of facial muscles and limb muscles by an intracortical microstimulation method. Microstimulation produced predominantly ipsilateral movement responses of facial muscles and contralateral responses in fore- and hindlimb muscles. Low-threshold stimulation in the left and right hemispheres showed a clear asymmetry of the motor representation of the facial muscles. Movement responses of the hindlimbs were obtained on microstimulation of the frontal regions of the neocortex, demonstrating the existence of multiple motor representations of muscles in the neocortex.

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The relationship between cortically induced mandibular movements and lateral pterygoid and digastric muscle EMG activity in the anesthetized guinea pig

Cited by 8 publications

References 20 publications

The effects of brain stem transections on the neuronal networks responsible for rhythmical jaw muscle activity in the guinea pig

The effects of brain stem transections on the neuronal networks responsible for rhythmical jaw muscle activity in the guinea pig

Brain-stem perturbations during cortically evoked rhythmical jaw movements: effects of activation of brain-stem loci on jaw muscle cycle characteristics

Functional mapping of the motor cortex of the white mouse by a microstimulation method

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