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Papers by Elizabeth Dobbins
Brain Research, 1992
Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brains... more Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brainstem site generating respiratory rhythm, are described in adult cats. Signals were recorded from neurons in the B6tzinger complex, pre-B6tzinger complex and rostral ventral respiratory group (rVRG) of anesthetized adult cats. The pre-B6tzinger complex, located caudal to expiratory-modulated B6tzinger neurons, contained a mix of neurons with inspiratory-modulated, expiratory-modulated, or phase-spanning patterns of impulse activity, in contrast to the more homogenous neuronal distributions characteristic of adjacent B6tzinger and rVRG regions.
The Journal of Comparative Neurology, 1994
Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources... more Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources that are not fully established. Bulbospinal (second-order) neurons projecting to phrenic motoneurons and propriobulbar (third-order) neurons projecting to these bulbospinal neurons were investigated in rat by transsynaptic transport of the neuroinvasive pseudorabies virus. Bulbospinal neurons were located predominantly in the medullary lateral tegmental field in two functionally described regions, the ventral respiratory group and Botzinger complex. An intervening region, the pre-Botzinger complex, contained essentially no phrenic premotoneurons. Bulbospinal neurons were also located in ventral, interstitial, and ventrolateral subnuclei of the solitary tract, and gigantocellular, Kolliker-Fuse, parabrachial, and medullary raphe nuclei. A monosynaptic pathway to phrenic motoneurons from the nucleus of the solitary tract was confirmed; monosynaptic pathways from upper cervical spinal cord, spinal trigeminal nucleus, medial and lateral vestibular nuclei, and medial pontine tegmentum were not verified. Locations of third-order neurons were consistent with described projections to the ventral respiratory group, from contralateral ventral respiratory group, Botzinger complex, A5 noradrenergic cell group, and the following nuclei: solitary, raphe, Kolliker-Fuse, parabrachial, retrotrapezoid, and paragigantocellular. Novel findings included a projection from locus coeruleus to respiratory premotoneurons and the lack of previously described pathways from area postrema and spinal trigeminal nucleus. These second-and third-order neurons form the output network for diaphragm motor control which includes numerous behaviors (e.g., respiration, phonation, defecation). Of the premotoneurons, the rostral ventral respiratory group is the primary population controlling phrenic motoneurons.
Brain Research, 1992
Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brains... more Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brainstem site generating respiratory rhythm, are described in adult cats. Signals were recorded from neurons in the B6tzinger complex, pre-B6tzinger complex and rostral ventral respiratory group (rVRG) of anesthetized adult cats. The pre-B6tzinger complex, located caudal to expiratory-modulated B6tzinger neurons, contained a mix of neurons with inspiratory-modulated, expiratory-modulated, or phase-spanning patterns of impulse activity, in contrast to the more homogenous neuronal distributions characteristic of adjacent B6tzinger and rVRG regions.
Journal of Comparative Neurology, 1994
Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources... more Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources that are not fully established. Bulbospinal (second-order) neurons projecting to phrenic motoneurons and propriobulbar (third-order) neurons projecting to these bulbospinal neurons were investigated in rat by transsynaptic transport of the neuroinvasive pseudorabies virus. Bulbospinal neurons were located predominantly in the medullary lateral tegmental field in two functionally described regions, the ventral respiratory group and Botzinger complex. An intervening region, the pre-Botzinger complex, contained essentially no phrenic premotoneurons. Bulbospinal neurons were also located in ventral, interstitial, and ventrolateral subnuclei of the solitary tract, and gigantocellular, Kolliker-Fuse, parabrachial, and medullary raphe nuclei. A monosynaptic pathway to phrenic motoneurons from the nucleus of the solitary tract was confirmed; monosynaptic pathways from upper cervical spinal cord, spinal trigeminal nucleus, medial and lateral vestibular nuclei, and medial pontine tegmentum were not verified. Locations of third-order neurons were consistent with described projections to the ventral respiratory group, from contralateral ventral respiratory group, Botzinger complex, A5 noradrenergic cell group, and the following nuclei: solitary, raphe, Kolliker-Fuse, parabrachial, retrotrapezoid, and paragigantocellular. Novel findings included a projection from locus coeruleus to respiratory premotoneurons and the lack of previously described pathways from area postrema and spinal trigeminal nucleus. These second-and third-order neurons form the output network for diaphragm motor control which includes numerous behaviors (e.g., respiration, phonation, defecation). Of the premotoneurons, the rostral ventral respiratory group is the primary population controlling phrenic motoneurons.
Journal of Comparative Neurology, 1995
Protrusion and retraction of the tongue are essential components of such orofacial behaviors as m... more Protrusion and retraction of the tongue are essential components of such orofacial behaviors as mastication, respiration, and swallowing. Stimulation of the medial branch of the hypoglossal nerve yields tongue protrusion, while stimulation of the lateral branch yields tongue retraction in rat. We exploited the transsynaptic transport capabilities of pseudorabies virus to determine specific circuits that innervate protruder and retractor muscles of the rat tongue. Each group of muscles is innervated by distinct populations of hypoglossal motoneurons: caudal ventral and ventrolateral motoneurons form the largest proportion of those innervating protruders, whereas rostra1 dorsal motoneurons innervate retractors. Our primary finding was differential innervation of protruder and retractor motoneurons by premotoneurons in the lateral tegmental field: premotoneurons innervating protruder motoneurons were more ventral and ventromedial than those innervating retractor motoneurons. In addition, protruder motoneurons received projections from the ipsilateral lateral parabrachial nucleus but not spinal trigeminal nucleus or medial and ventral subnuclei of the solitary tract; the converse was true for retractor motoneurons. These results suggest segregation of functional networks that control hypoglossal motoneurons. The dorsal medulla, in or around the solitary tract, contains neurons specific to retractor motoneurons, and the region ventrolateral to the hypoglossal nucleus contains circuitry specific to protruder motoneurons. Common innervation of medial and lateral branch motoneurons is provided by premotoneurons in the raphe and gigantocellular reticular formation of the medial medulla. The midline medullary nuclei with diverse projections may coordinate complex behavior or modulate general motoneuron excitability, whereas the lateral reticular formation, with anatomically discrete projections, may control motoneurons that contribute to distinct orofacial behaviors. G 1~~5 Wilep-Liss, Inc.
Brain Research, 1992
Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brains... more Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brainstem site generating respiratory rhythm, are described in adult cats. Signals were recorded from neurons in the B6tzinger complex, pre-B6tzinger complex and rostral ventral respiratory group (rVRG) of anesthetized adult cats. The pre-B6tzinger complex, located caudal to expiratory-modulated B6tzinger neurons, contained a mix of neurons with inspiratory-modulated, expiratory-modulated, or phase-spanning patterns of impulse activity, in contrast to the more homogenous neuronal distributions characteristic of adjacent B6tzinger and rVRG regions.
The Journal of Comparative Neurology, 1994
Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources... more Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources that are not fully established. Bulbospinal (second-order) neurons projecting to phrenic motoneurons and propriobulbar (third-order) neurons projecting to these bulbospinal neurons were investigated in rat by transsynaptic transport of the neuroinvasive pseudorabies virus. Bulbospinal neurons were located predominantly in the medullary lateral tegmental field in two functionally described regions, the ventral respiratory group and Botzinger complex. An intervening region, the pre-Botzinger complex, contained essentially no phrenic premotoneurons. Bulbospinal neurons were also located in ventral, interstitial, and ventrolateral subnuclei of the solitary tract, and gigantocellular, Kolliker-Fuse, parabrachial, and medullary raphe nuclei. A monosynaptic pathway to phrenic motoneurons from the nucleus of the solitary tract was confirmed; monosynaptic pathways from upper cervical spinal cord, spinal trigeminal nucleus, medial and lateral vestibular nuclei, and medial pontine tegmentum were not verified. Locations of third-order neurons were consistent with described projections to the ventral respiratory group, from contralateral ventral respiratory group, Botzinger complex, A5 noradrenergic cell group, and the following nuclei: solitary, raphe, Kolliker-Fuse, parabrachial, retrotrapezoid, and paragigantocellular. Novel findings included a projection from locus coeruleus to respiratory premotoneurons and the lack of previously described pathways from area postrema and spinal trigeminal nucleus. These second-and third-order neurons form the output network for diaphragm motor control which includes numerous behaviors (e.g., respiration, phonation, defecation). Of the premotoneurons, the rostral ventral respiratory group is the primary population controlling phrenic motoneurons.
Brain Research, 1992
Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brains... more Patterns of respiratory neuronal discharge in the pre-B6tzinger complex, hypothesized as a brainstem site generating respiratory rhythm, are described in adult cats. Signals were recorded from neurons in the B6tzinger complex, pre-B6tzinger complex and rostral ventral respiratory group (rVRG) of anesthetized adult cats. The pre-B6tzinger complex, located caudal to expiratory-modulated B6tzinger neurons, contained a mix of neurons with inspiratory-modulated, expiratory-modulated, or phase-spanning patterns of impulse activity, in contrast to the more homogenous neuronal distributions characteristic of adjacent B6tzinger and rVRG regions.
Journal of Comparative Neurology, 1994
Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources... more Contraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources that are not fully established. Bulbospinal (second-order) neurons projecting to phrenic motoneurons and propriobulbar (third-order) neurons projecting to these bulbospinal neurons were investigated in rat by transsynaptic transport of the neuroinvasive pseudorabies virus. Bulbospinal neurons were located predominantly in the medullary lateral tegmental field in two functionally described regions, the ventral respiratory group and Botzinger complex. An intervening region, the pre-Botzinger complex, contained essentially no phrenic premotoneurons. Bulbospinal neurons were also located in ventral, interstitial, and ventrolateral subnuclei of the solitary tract, and gigantocellular, Kolliker-Fuse, parabrachial, and medullary raphe nuclei. A monosynaptic pathway to phrenic motoneurons from the nucleus of the solitary tract was confirmed; monosynaptic pathways from upper cervical spinal cord, spinal trigeminal nucleus, medial and lateral vestibular nuclei, and medial pontine tegmentum were not verified. Locations of third-order neurons were consistent with described projections to the ventral respiratory group, from contralateral ventral respiratory group, Botzinger complex, A5 noradrenergic cell group, and the following nuclei: solitary, raphe, Kolliker-Fuse, parabrachial, retrotrapezoid, and paragigantocellular. Novel findings included a projection from locus coeruleus to respiratory premotoneurons and the lack of previously described pathways from area postrema and spinal trigeminal nucleus. These second-and third-order neurons form the output network for diaphragm motor control which includes numerous behaviors (e.g., respiration, phonation, defecation). Of the premotoneurons, the rostral ventral respiratory group is the primary population controlling phrenic motoneurons.
Journal of Comparative Neurology, 1995
Protrusion and retraction of the tongue are essential components of such orofacial behaviors as m... more Protrusion and retraction of the tongue are essential components of such orofacial behaviors as mastication, respiration, and swallowing. Stimulation of the medial branch of the hypoglossal nerve yields tongue protrusion, while stimulation of the lateral branch yields tongue retraction in rat. We exploited the transsynaptic transport capabilities of pseudorabies virus to determine specific circuits that innervate protruder and retractor muscles of the rat tongue. Each group of muscles is innervated by distinct populations of hypoglossal motoneurons: caudal ventral and ventrolateral motoneurons form the largest proportion of those innervating protruders, whereas rostra1 dorsal motoneurons innervate retractors. Our primary finding was differential innervation of protruder and retractor motoneurons by premotoneurons in the lateral tegmental field: premotoneurons innervating protruder motoneurons were more ventral and ventromedial than those innervating retractor motoneurons. In addition, protruder motoneurons received projections from the ipsilateral lateral parabrachial nucleus but not spinal trigeminal nucleus or medial and ventral subnuclei of the solitary tract; the converse was true for retractor motoneurons. These results suggest segregation of functional networks that control hypoglossal motoneurons. The dorsal medulla, in or around the solitary tract, contains neurons specific to retractor motoneurons, and the region ventrolateral to the hypoglossal nucleus contains circuitry specific to protruder motoneurons. Common innervation of medial and lateral branch motoneurons is provided by premotoneurons in the raphe and gigantocellular reticular formation of the medial medulla. The midline medullary nuclei with diverse projections may coordinate complex behavior or modulate general motoneuron excitability, whereas the lateral reticular formation, with anatomically discrete projections, may control motoneurons that contribute to distinct orofacial behaviors. G 1~~5 Wilep-Liss, Inc.