Bilateral Brainstem Connections of the Rat Supratrigeminal Region

Rokx, J.T.M.; Willigen, J.D. van; Jüch, P.J.W.

doi:10.1159/000146234

Cited by 34 publications

(9 citation statements)

References 5 publications

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“…Although we have a reasonably good understanding of the neuronal circuits responsible for a number of oralmotor reflexes (see Lund, 1991;Nakamura and Katakura, 1995), the precise identity of the constituent neurons of the central circuits, known as central pattern generators (CPGs), underlying oral-motor rhythmic movements such as suckling and mastication remain elusive. Nevertheless, progress has been made in defining (1) the minimal regions of the brain stem compatible with oral-motor rhythmic activity (Chandler and Tal, 1986;Tanaka et al, 1999), (2) synaptic interconnections between trigeminal interneuronal nuclei in those regions (Mizuno, 1970;Rokx et al, 1986;Bourque and Kolta, 2001), and (3) intrinsic membrane properties and discharge characteristics of neurons in those regions (Inoue et al, 1992Bourque and Kolta, 2001;Min et al, 2003;among others). In the present study we found that a small population of SupV neurons exhibit conditional burst-generating properties that are most associated with multipolar neurons that discharge in either tonic or delayed-firing mode.…”

Section: Discussionmentioning

confidence: 99%

Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region

Hsiao

Gougar

Asai

et al. 2007

J of Neuroscience Research

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The membrane properties and morphological features of interneurons in the supratrigeminal area (SupV) were studied in rat brain slices using whole-cell patch clamp recording techniques. We classified three morphological types of neurons as fusiform, pyramidal, and multipolar and four physiological types of neurons according to their discharge pattern in response to a 1-sec depolarizing current pulse from -80 mV. Single-spike neurons responded with a single spike, phasic neurons showed an initial burst of spikes and were silent during the remainder of the stimulus, delayed-firing (DF) neurons exhibited a slow depolarization and delay to initial spike onset, and tonic (T) neurons showed maintained a discharge throughout the stimulus pulse. In a subpopulation of neurons (10%), membrane depolarization to around -44 mV produced a rhythmic burst discharge (RB) that was associated with voltage-dependent subthreshold membrane oscillations. Both these phenomena were blocked by the sodium channel blocker riluzole at a concentration that did not affect the fast transient spike. Low doses of 4-AP, which blocks low-threshold K+ currents, transformed bursting into low-frequency tonic discharge. In contrast, bursting occurred with exposure to cadium, a calcium-channel blocker. This suggests that persistent sodium currents and low-threshold K+ currents have a role in intrinsic burst generation. Importantly, RB cells were most often associated with multipolar neurons that exhibited either a DF or a T discharge. Thus, the SupV contains a variety of physiological cell types with unique morphologies and discharge characteristics. Intrinsic bursting neurons form a unique group in this region. .

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Section: Discussionmentioning

confidence: 99%

Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region

Hsiao

Gougar

Asai

et al. 2007

J of Neuroscience Research

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“…Supporting this finding, Grofova and Keane (1991) reported a sparse, yet consistent, projection from the PPTg to the lateral facial motor neurons by using anterograde tract tracing. Combined with our present data, these findings clearly demonstrate that the PPTg is an important source of input to wFMNs.Sparse to moderate anterograde and retrograde labeling was also observed bilaterally in the pontine reticular nucleus, in the subpeduncular tegmental nucleus, and in the subcoeruleus Rokx et al (1986) demonstrated that the supratrigeminal nucleus projects to intermediate and dorsal regions of the facial nucleus and only rarely to the lateral facial nucleus. Thus, the scarcity of retrograde labeling in the supratrigeminal nucleus in our study indicates that our injections were indeed confined to the lateral subdivision of the facial nucleus.…”

mentioning

confidence: 88%

“…Components of the motor trigeminal complex, including the motor trigeminal and supratrigeminal nuclei, contained no, or only sparse, labeled neurons and terminals. Significantly, an anterograde tract-tracing study by Rokx et al (1986) demonstrated that the supratrigeminal nucleus projects to intermediate and dorsal regions of the facial nucleus and only rarely to the lateral facial nucleus. Thus, the scarcity of retrograde labeling in the supratrigeminal nucleus in our study indicates that our injections were indeed confined to the lateral subdivision of the facial nucleus.…”

Section: Labeling In the Metencephalonmentioning

confidence: 99%

Functional circuitry involved in the regulation of whisker movements

Hattox

Priest

Keller

2001

J of Comparative Neurology

155

143

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Neuroanatomical tract-tracing methods were used to identify the oligosynaptic circuitry by which the whisker representation of the motor cortex (wMCx) influences the facial motoneurons that control whisking activity (wFMNs). Injections of the retrograde tracer cholera toxin subunit B into physiologically identified wFMNs in the lateral facial nucleus resulted in dense, bilateral labeling throughout the brainstem reticular formation and in the ambiguus nucleus as well as predominantly ipsilateral labeling in the paralemniscal, pedunculopontine tegmental, Kölliker-Fuse, and parabrachial nuclei. In addition, neurons in the following midbrain regions projected to the wFMNs: superior colliculus, red nucleus, periaqueductal gray, mesencephalon, pons, and several nuclei involved in oculomotor behaviors. Injections of the anterograde tracer biotinylated dextran amine into the wMCx revealed direct projections to the brainstem reticular formation as well as multiple brainstem and midbrain structures shown to project to the wFMNs. Regions in which retrograde labeling and anterograde labeling overlap most extensively include the brainstem parvocellular, gigantocellular, intermediate, and medullary (dorsal and ventral) reticular formations; ambiguus nucleus; and midbrain superior colliculus and deep mesencephalic nucleus. Other regions that contain less dense regions of combined anterograde and retrograde labeling include the following nuclei: the interstitial nucleus of medial longitudinal fasciculus, the pontine reticular formation, and the lateral periaqueductal gray. Premotoneurons that receive dense inputs from the wMCx are likely to be important mediators of cortical regulation of whisker movements and may be a key component in a central pattern generator involved in the generation of rhythmic whisking activity. Keywordscentral pattern generator; motor cortex; facial nucleus; brainstem; rat Production of rhythmic whisker movements ("whisking") is a critical exploratory behavior in several mammalian species (see, e.g., Vincent, 1912;Brecht et al., 1997) and is emerging as a model system for studying mechanisms of voluntary movements (Kleinfeld et al., 1997). Whisking consists of large-amplitude protractions of the large mystacial vibrissae, with spectral components between 6 and 9 Hz (Semba and Komisaruk, 1984). The whisker representation of the motor cortex (wMCx) occupies approximately one-third of the rodent motor cortex, and low-intensity stimulation of this region evokes whisker protractions (Donoghue and Wise, 1982;Weiss and Keller, 1994). The patterns of afferent, efferent, and intracortical connections of the wMCx suggest that the area is devoted primarily to regulating whisker movements (Donoghue and Parham, 1983;Miyashita et al., 1994;Weiss and Keller, 1994). However, the mechanisms by which the wMCx regulates whisking are at present unknown. Support for a role of the wMCx in regulating whisking is derived from studies demonstrating correlations between wMCx unit activity and EMG recorded from the whis...

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“…The RF surrounding 5N projects bilaterally to 5N and includes cells in the supratrigeminal nucleus (Su5) located dorsal to 5N, the intertrigeminal nucleus (I5) interposed between 5N and the principal trigeminal sensory nucleus, and the juxtatrigeminal area (Jx5) ventral to 5N (Travers and Norgren, 1983;Vornov and Sutin, 1983;Rokx et al, 1986;Appenteng et al, 1990;Yoshida et al, 2009). More recently, the region just medial to the ventromedial subdivision of 5N (MPe5) has been identified as having a close association with adjacent jaw-opener motoneurons (McDavid et al, 2006;Yoshida et al, 2009).…”

Section: Pontine Projectionsmentioning

confidence: 99%

Oromotor Nuclei

Travers

2015

The Rat Nervous System

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Bilateral Brainstem Connections of the Rat Supratrigeminal Region

Cited by 34 publications

References 5 publications

Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region

Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region

Functional circuitry involved in the regulation of whisker movements

Oromotor Nuclei

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