Principal Trigeminal Nucleus


In the present study, we show that in sharp contrast to the relay cells of the barreloids VPMvl neurons exhibit large multiwhisker receptive fields that are independent of input from the principal trigeminal nucleus.  

Together, these different approaches provide conclusive evidence that the principal trigeminal nucleus receives inhibitory GABAergic projections from the caudal sector of the interpolaris subnucleus, and excitatory glutamatergic projections from the caudalis subnucleus.  

This pathway arises from multiwhisker-responsive cells in the principal trigeminal nucleus and differs from the classic lemniscal pathway, in that constituent thalamic cells have multiwhisker receptive field and receive corticothalamic input from lamina 6 of the vibrissa motor cortex.  

The lemniscal pathway includes the principal trigeminal nucleus (Pr5) and the ventral posteromedial thalamic nucleus (VPm).  

Injections of Fast Blue (FB) into PML and Diamidino Yellow (DY) into the uvula, resulted in prominent labeling neurons with FB bilaterally and with DY ipsilaterally, in the principal trigeminal nucleus, subnucleus oralis, and rostral and caudal subnucleus interpolaris.  

Such enlargement is not observed at the level of the principal trigeminal nucleus, indicating that it originates within the thalamus.  

The principal trigeminal nucleus and the oralis and interpolaris spinal trigeminal nuclei were substantially larger in the platypus than in either the echidna or rat, but the caudalis subnucleus was similar in size in both monotremes and the rat.  

Addicsin transcripts were also extremely abundant in trigeminal neurons such as the principal trigeminal nucleus, mesencephalic trigeminal nucleus and motor trigeminal nucleus.  

KCC2 mRNA was expressed in the motor trigeminal nucleus (Mo5), the principal trigeminal nucleus (Pr5), and the spinal trigeminal nucleus (Sp5), but not in the trigeminal ganglion (TG) and the mesencephalic trigeminal nucleus (Me5).  

The present experiments were undertaken to separate the contribution of the principal trigeminal nucleus (PrV) from that of the spinal trigeminal nucleus (SpV) to whisker evoked responses in the ventral posterior medial (VPM) nucleus in the adult rat thalamus.  

Sparse projections to the spinal trigeminal nucleus, pars oralis and the principal trigeminal nucleus were also detected. Central terminations from the frontal nerve were present in the principal trigeminal nucleus and throughout the spinal trigeminal nucleus, but were most prominent within the dorsal horn of the first cervical segment.  

Startle responses are elicited by either intense noise bursts or electrical stimulation of the principal trigeminal nucleus.  

The present study was undertaken to determine the extent and distribution of trigeminal terminations within the facial lobe (FL) and principal trigeminal nucleus (nVpr) in the channel catfish, Ictalurus punctatus.  

Corresponding to these two classes of fibers, 67% of the cells in the principal trigeminal nucleus (n = 313) have single-whisker receptive fields, whereas the rest of the population have receptive fields composed of multiple whiskers.  

Transient electrical stimulation of the inferior colliculus (IC) of adult male rats had a strong and long-lasting inhibitory effect on startle responses elicited by either intense noise bursts or unilateral electrical stimulation of the principal trigeminal nucleus.  

They suggest that in patients with hypoglossal-facial (XII-VII) nerve anastomosis, the short-latency trigemino-'hypoglossal-facial' reflex of the R1 blink reflex type observed in facial muscles following supraorbital nerve stimulation could be due to changes in synaptic effectiveness of the central connectivity within the principal trigeminal nucleus where both cutaneous and mucosal trigeminal afferents project..  

The principal trigeminal nucleus also contains neurons with tonic firing ability, compatible with simple rate coding..  

Capsaicin caused no change in the pattern or size of cytochrome oxidase (CO) barrelettes in the principal trigeminal nucleus (Vp) or trigeminal nucleus interpolaris (Vi) or caudalis (Vc).  

Injections of WGA-HRP were placed into the principal trigeminal nucleus (Vp) and into all divisions of the spinal trigeminal nucleus.  

Weak afferent inputs from the periorbital skin are present ventrally in pars oralis of the spinal trigeminal nucleus (Vo) and in the principal trigeminal nucleus (Vp).  

Cell body silhouette area was determined for spherical bushy cells of the anteroventral cochlear nucleus (AVCN), pyramidal cells of the dorsal cochlear nucleus (DCN), sensory neurons from the principal trigeminal nucleus, and motoneurons of the facial nucleus.  

The corticobulbar fibers left the pyramid along its entire extent; the principal trigeminal nucleus and the dorsolateral pontine tegmentum were supplied by additional fibers of the corticotegmental tract.  

Induced neurons were distributed throughout the ipsilateral subnucleus interpolaris, principal trigeminal nucleus, and intertrigeminal nucleus.  

Direct trigeminocerebellar fibres originated mostly in the principal trigeminal nucleus (VP) and pars oralis (Vo), pars interpolaris (Vi), and to a lesser extent in pars caudalis (Vc) of the spinal trigeminal nucleus.  

Labeled IXN fibers extended rostrally to the principal trigeminal nucleus and caudally to the cervical spinal cord.  

The first afferents from the principal trigeminal nucleus arrive between 10 and 15 days postnatal.  

The major projections originate mainly from the dorsolateral and ventromedial regions of the principal trigeminal nucleus (Vp) except its caudal pole.  

No immunoreactivity was observed in the subnucleus interpolaris, subnucleus oralis spinal trigeminal nucleus complex (STNC), principal trigeminal nucleus and mesencephalic trigeminal nucleus of the experimental rats and all the trigeminal nuclei of control animals.  

The subnucleus interporalis and the subnucleus oralis of the spinal trigeminal nucleus complex, the principal trigeminal nucleus and the mesencephalic trigeminal nucleus of the experimental animals and all the trigeminal nuclei of the control animals contained no immunopositive cells.  

Ascending fibers innervate the principal trigeminal nucleus, a field just dorsal to the trigeminal motor nucleus, and the supratrigeminal nucleus.  

Sensory inputs to the red nucleus originate in the contralateral dorsal column nuclei, the principal trigeminal nucleus, and the spinothalamic system.  

A few retrogradely labeled cells were found in the vagus-solitarius complex, the principal trigeminal nucleus and the high cervical spinal cord.  

A total of 47 neurons were isolated and most neurons were located near the dorsomedial border of the rostral trigeminal subnucleus oralis and caudal principal trigeminal nucleus.  

These data indicate that despite the heterotopical sprouting of some axons of neurones from the principal trigeminal nucleus towards the XIIth nucleus, those hypoglossal motoneurones involved in the neoformated trigemino-hypoglossal reflex arc remain totally inexcitable by other trigeminal afferents and thus appear unable to ensure the physiological function of the normal blink reflex..  

Two regions of the inferior olive-the medial dorsal accessory olive and the ventral leaf of the principal olive-receive inputs from pars interpolaris (Vi) and rostral pars caudalis (Vc) of the spinal trigeminal nucleus and from the principal trigeminal nucleus (Vp).  

Pyknotic figure counts in the principal trigeminal nucleus and in each of the three spinal trigeminal subnuclei revealed that cell death commences at E19, in the region of the junction between the principal nucleus and the subnucleus oralis, close to the site of entry of trigeminal afferents into the brainstem.  

Anterograde tracing studies reveal that the rod domain in VPM is innervated by fibers arising in the contra- and ipsilateral principal trigeminal nucleus, while the matrix domain (and calbindin-positive domains in adjacent nuclei) are innervated by fibers arising in the caudal nucleus of the spinal trigeminal complex.  

Strongly- or moderately-labeled neurons were found in the cranial nuclei, sensory nuclei such as the spinal trigeminal nucleus, principal trigeminal nucleus, gracile and cuneate nuclei, dorsal and ventral cochlear nuclei, superior olivary nucleus, medial and lateral trapezoid nuclei, lateral lemniscus and vestibular nuclei, red nucleus, parabrachial area, cerebellar nuclei, dorsal tegmental nucleus, reticular formation and parafascicular nucleus.  

There was terminal label from the CT also in the principal trigeminal nucleus. There was terminal label from the CT also in the principal trigeminal nucleus and the oral and intermediate divisions of the spinal trigeminal nucleus. There were also labeled terminals in the principal trigeminal nucleus and in all three divisions of the spinal trigeminal nucleus.  

The cells arising from the Vc project to all rostral trigeminal nuclei except the caudal Vi and dorsal part of the principal trigeminal nucleus (Vpd), and neurons of the caudal Vi project to the dorsomedial (Vo.dm) and rostrodorsomedial (Vo.r) divisions of the spinal trigeminal nucleus and the ventral part of the principal trigeminal nucleus (Vpv), although the main ascending fibers from the Vc arise from laminae III-V and project to the rostral Vi and pars oralis.  

The results indicated that these afferents were derived from the following brainstem areas: the dorsal red nucleus and the mesencephalic tegmentum dorsal to it; the olivary pretectal nucleus and/or the nucleus of the optic tract; the dorsolateral pontine tegmentum (parabrachial nuclei and nucleus of K├Âlliker-Fuse) and principal trigeminal nucleus; the ventrolateral pontine tegmentum at the level of the motor trigeminal nucleus; the caudal medullary medial tegmentum; the lateral tegmentum at the level of the rostral pole of the hypoglossal nucleus and the ventral part of the trigeminal nucleus and the nucleus raphe pallidus and caudal raphe magnus including the adjoining medullary tegmentum.  

The extent of the VPM occupied by terminations of afferent fibers arising in the ipsilateral principal trigeminal nucleus was also determined by anterograde transport of horseradish peroxidase.  

The trigeminal and glossopharyngeal ganglia of the adult mallard were studied following HRP injections into the principal trigeminal nucleus (PrV). The PrV consists of the principal trigeminal nucleus proper (prV) and the principal glossopharyngeal nucleus (prIX).  

During the second postnatal week, corticotrigeminal axons grow out of the pyramidal tract in a caudal to rostral sequence and project up to the ventromedial borders of Vs-interpolaris, Vs-oralis, and to the principal trigeminal nucleus. Coincident with the development of cortical projections to the principal trigeminal nucleus, some of the labeled axons which were in lamina III of Vs-caudalis project into lamina I and terminate.  

Either Fast Blue or True Blue was injected into the ventrobasal thalamus while Nuclear Yellow later was deposited into either the principal trigeminal nucleus or the cerebellum.  

Central projections of these neurons are to nuclei of the descending trigeminus and to largely nonoverlapping portions of the principal trigeminal nucleus.  

Unit activity evoked by tactile stimulation of the face skin was also recorded from the region of the principal trigeminal nucleus in the medulla.  

Bilateral projections were demonstrated from the principal trigeminal nucleus to the telencephalon, reminiscent of the quintofrontal tract of birds.  

In the trigeminal complex of the medulla, three parallel representation can be seen, two in the spinal trigeminal nucleus and one in the principal trigeminal nucleus.  

The main inputs subserving the tactile pathway are the principal trigeminal nucleus and the rostral portion of the spinal V subnucleus oralis and the main cuneate nucleus.  

The ascending fibers distribute in a compact and circumscribed zone immediately dorsal to the spinal V nucleus as far rostral as the caudal pole of the principal trigeminal nucleus.  

Results showed brainstem projections from nucleus caudalis to rostral levels of the spinal trigeminal complex, to the ventral division of the principal trigeminal nucleus, the parabrachial nucleus, cranial motor nuclei 7 and 12, solitary complex, contralateral dorsal inferior olivary nucleus, portions of the lateral reticular formation, upper cervical spinal dorsal horn and, lateral cervical nucleus.  


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