Trigeminal Sensory Complex Research Articles

Physiological properties of neurons in different parts of the cat trigeminal sensory complex : Brain Res., 246 (1982) 7–21

Physiological properties of neurons in different parts of the cat trigeminal sensory complex : Brain Res., 246 (1982) 7–21

The properties of cells in the cat trigeminal main sensory and spinal subnuclei activated by mechanical stimulation of the periodontium

Neurophysiological exploration of the trigeminal sensory complex was done on 42 cats under ketamine anaesthesia, paying special attention to units receiving a periodontal input. Among 492 cells recorded in the trigeminal sensory complex, 73 responded to mechanical stimulation of the periodontium and were precisely localized histologically. Thalamic stimulation was also delivered to the ipsi and contralateral ventro-posterior nucleus to test for antidromic responses. Results of this systematic study were plotted on reference drawings of the full extent of the trigeminal sensory complex.

The nictitating membrane response: An electrophysiological study of the abducens nerve and nucleus and the accessory abducens nucleus in rabbit

The nictitating membrane response to periocular electrostimulation was investigated in anesthetized and paralyzed rabbits. Recordings from the abducens nerve, which carries the fibers innervating retractor bulbi muscles that are primarily involved in this reflex, showed two distinct volleys to effective stimulation: a short duration volley with a minimum latency of approximately 4 ms and a longer duration volley beginning approximately 10 ms after stimulus onset and lasting up to 25 ms. Recordings of antidromically evoked field potentials via microelectrodes indicated large responses to abducens nerve stimulation in the vicinity of the accessory abducens nucleus. Single unit recordings from the accessory abducens nucleus produced spike trains with minimal latencies of 3.7–5 ms to eyeshock. The latency of spike discharge was inversely related to stimulus current. Units in the abducens nucleus did not show stimulus-elicited spiking, suggesting that the accessory abducens, but not the abducens, is primarily involved in the reflex pathway. Transverse knife cuts which separated caudal areas of the sensory trigeminal complex from the accessory abducens nucleus did not attenuate the efferent volley to suprathreshold stimulation, suggesting that more rostral components of the trigeminal complex are primarily involved in the reflex pathway.

Physiological properties of neurons in different parts of the cat trigeminal sensory complex

The following points emerge from a systematic investigation of the 4 divisions of the cat trigeminal sensory complex. (1) The subnucleus oralis receives a large representation from the oral cavity, a region also represented in the 3 other divisions of the trigeminal sensory complex. (2) Nucleus principalis cells project heavily to the contralateral and to the ipsilateral ventroposterior thalamus. Ipsilateral projections are only from the oral cavity representation. (3) Units responding to noxious mechanical stimulation have been found at two different loci: the subnucleus caudalis for the entire trigeminal area, and subnucleus oralis for the oral cavity alone. (4) The dental pulp projects to the 4 divisions of the trigeminal sensory complex, but the heaviest projection was found in the rostral part (nucleus principalis and subnucleus oralis). (5) Three distinct types of post-synaptic responses were found to be evoked by dental pulp stimulation: (a) short latency, consistent and synaptically secure, (b) strongly variable latency, inconstant and easily fatigued and (c) a class showing progressive enhancement by progressive increase in stimulus intensity and repetition.

Corneal and periocular representation within the trigeminal sensory complex in the cat studied with transganglionic transport of horseradish peroxidase.

The central projections of afferent fibers from the cornea, and the infraorbital, infratrochlear, frontal, lacrimal and auriculotemporal nerves were investigated by means of the transganglionic transport of horseradish peroxidase. Afferent projections to the dorsal horn of the medulla are organized along both the rostrocaudal axis and the ventrolateral to dorsomedial margin of the medullary dorsal horn. An inverted but discontinuous facial representation exists through the restrocaudal axis of the dorsal horn of the medulla with perioral and nasal receptive fields innervated by the infratrochlear nerves represented rostral to the progressively more posterior receptive fields innervated by the frontal, lacrimal and auriculotemporal nerves, respectively. The organization of the primary afferents is not uniform over the laminae of the dorsal horn of the medulla; the projections from the different nerves show the least overlap in lamina II, while overlap is most extensive in laminae I and V. The sensory projection from the cornea to the medullary dorsal horn is most dense in laminae I and II. All nerves, including those innervating the cornea, project to the interpolar, oral and principal trigeminal nuclei and are somatotopically organized. Projections to the reticular formation and the contralateral trigeminal sensory complex were not found in this study. These results support the organization of the dorsal horn of the medulla proposed by Déjerine ('14) and show that this organization is most evident for the primary afferent projections to lamina II.

An HRP study of the central projections of primary trigeminal neurons which innervate tooth pulps in the cat

Trigeminal ganglia and brain stem of adult cats were studied following HRP injections into tooth pulps or after exposure of the cut end of the inferior alveolar nerve to HRP. Ipsilateral ganglion cells within a wide range of sizes were labeled in both experimental situations, whereas no labeled cells were observed in the contralateral ganglion in any animal. Labeled central branches of tooth pulp and inferior alveolar neurons were observed in all subdivisions of the ipsilateral trigeminal sensory complex. Terminal labeling in the tooth pulp experiments was confined to the dorsomedial parts of the main sensory nucleus and subnuclei oralis and interpolaris. Caudal to the obex terminal labeling was restricted to the medial halves of laminae I, IIa and V of the medullary dorsal horn. In the inferior alveolar nerve experiments dense terminal labeling was observed in the dorsal parts of the main sensory nucleus and subnuclei oralis and interpolaris. Caudal to the obex terminal labeling was located throughout laminae I to V in contrast to the tooth pulp experiments. Neither of the two experimental situations offers any evidence for a bilateral or contralateral brain stem projection of primary trigeminal neurons.

Functional properties of neurons in cat trigeminal subnucleus caudalis (medullary dorsal horn). II. Modulation of responses to noxious and nonnoxious stimuli by periaqueductal gray, nucleus raphe magnus, cerebral cortex, and afferent influences, and effect of naloxone.

Functional properties of neurons in cat trigeminal subnucleus caudalis (medullary dorsal horn). II. Modulation of responses to noxious and nonnoxious stimuli by periaqueductal gray, nucleus raphe magnus, cerebral cortex, and afferent influences, and effect of naloxone.

Properties and projection sites of rostral trigeminal sensory complex units activated by noxious and non noxious stimuli in the rat

Properties and projection sites of rostral trigeminal sensory complex units activated by noxious and non noxious stimuli in the rat

Bilateral projection of canine tooth pulps to neurons of the cat sensory trigeminal complex

The sensory trigeminal nuclei of cats were explored bilaterally with tungsten microelectrodes until neurons responsive to electrical stimulation of each canine tooth pulp were located. Then, the right trigeminal ganglion was transected and exploration was resumed. Stimulation of the left teeth generated 124 single-unit responses in 34 penetrations into the brain stem and evoked field potentials in 10 others after ganglionectomy. Although both left and right nuclear complexes yielded evoked activity, unit responses were obtained more frequently and field potentials attained higher amplitudes on the left. Stimulation of the right teeth, in contrast, triggered no unit discharges and evoked no field potentials in 51 postganglionectomy nuclear penetrations. Similarly, conditioning stimuli applied to the right teeth after ganglionectomy had no effect upon the responses to test stimuli applied to the left teeth. The data corroborate previous observations that many neurons in the trigeminal complex are innervated by bilateral projections from the canine dental pulps. In addition, they provide evidence that the projection from the contralateral canines is composed of primary and higher order afferent fibers which cross the midline exclusively within the brain stem to form a medullary-pontine pulpal decussation.

Sources of subcortical projections to the superior colliculus in the cat.

A comprehensive search for subcortical projections to the cat superior colliculus was conducted using the retrograde horseradish peroxidase (HRP) method. Over 40 different subcortical structures project to the superior colliculus. The more notable among these are grouped under the following categories. Visual structures: ventral lateral geniculate nucleus, parabigeminal nucleus, pretectal area (nucleus of the optic tract, posterior pretectal nucleus, nuclei of the posterior commissure). Auditory structures: inferior colliculus (external and pericentral nuclei), dorsomedial periolivary nucleus, nuclei of the trapezoid body, ventral nucleus of the lateral lemniscus. Somatosensory structures: sensory trigeminal complex (all divisions, but mainly the gamma division of nucleus oralis), dorsal column nuclei (mostly cuneate nucleus), and the lateral cervical nucleus. Catecholamine nuclei: locus coeruleus, raphe dorsalis, and the parabrachial nuclei. Cerebellum: medial, interposed, and lateral nuclei, and the perihypoglossal nuclei. Reticular areas: zona incerta, substantia nigra, midbrain tegmentum, nucleus paragigantocellularis lateralis, and the hypothalamus. Evidence is presented that only the parabigeminal nucleus, the nucleus of the optic tract, and the posterior pretectal nucleus project to the superficial collicular layers (striatum griseum superficiale and stratum opticum), while all other afferents terminate in the deeper layers of the colliculus. Also presented is information concerning the rostrocaudal distribution of some of these afferent connections. These findings stress the multiplicity and diversity of inputs to the deeper collicular layers, and more specifically, identify multiple sources of the physiologically well-known representations of the somatic and auditory modalities in the colliculus.

Evidence for primary afferent depolarization of single tooth-pulp afferents in the cat.

1. Responses of single tooth-pulp afferents to electrical stimulation of sites in the trigeminal sensory nuclear complex were recorded from caine teeth in cats. 2. Changes in the excitability of the central terminals of a pulpal afferent after stimulation of other groups of sensory nerves were taken as evidence for changes in their polarization. 3. Electrical stimulation of nerves in other teeth resulted in raised excitability of the central terminals of pulpal afferents lasting up to 300 msec. The greatest effects were observed 30--100 msec after the conditioning stimulus. 4. Increased terminal excitability was also observed after the ipsilateral infraorbital nerve was stimulated. This occurred when only nerve fibres with conduction velocities in the A alpha range were excited. 5. Mechanical stimulation of a canine tooth produced increases in terminal excitability of pulpal afferents innervating the same tooth. 6. A similar effect was also observed after a brief pull on a group of ipsilateral mystacial vibrissae. 7. No evidence of decreases in the excitability of the central terminals of tooth-pulp afferents was obtained with any of the conditioning stimuli.

Organization of trigeminothalamic tracts and other thalamic afferent systems of the brainstem in the rat: Presence of gelatinosa neurons with thalamic connections

Thalamic projections from trigeminal and certain other nuclei of the brainstem of the rat have been investigated using the technique of retrograde transport of horseradish peroxidase (HRP). The pattern of trigeminothalamic projections is very specifically related to the individual subnuclei of the complex. The Main Sensory Nucleus (MSN) provides profuse cross connections to the ventrobasal thalamus (VB); these arise exclusively from medium and small-sized neurons, but never from the large cells. In addition to these crossed connections, a small ipsilateral dorsal trigeminothalamic tract arises from the dorsal third of the most rostral part of the MSN; this is the only ipsilateral connection to VB found in the trigeminal complex. Subnucleus Oralis has no projections to the thalamus; it is suggested that it may be concerned primarily with reflex activation of the facial nucleus, with which it is co-extensive in the rostro-caudal axis. Subnucleus Interpolaris has a well-defined crossed projection of moderate size which arises from the large, medium and some of the small neurons. Subnucleus Caudalis has a sparse output to the thalamus and differs in its projections from rostral to caudal. At the most rostral level, all layers (marginal, transitional gelatinosa and magnocellularis) contain neurons which project to the thalamus; particularly conspicuous in this respect are the marginal neurons, most of which are strongly labelled. The presence of gelatinosa neurons projecting to the thalamus emphasizes a point made in earlier reports, that these neurons do not form an homogeneous population. At caudal levels, the marginal neurons are the major source of thalamic projections, while connections to the thalamus form deeper lying neurons are infrequent. With a single exception, the medullary reticular nuclei contained no neurons with thalamic connections; a small number of reticulo-thalamic neurons were found in the ventral pontine area. Marked labelling of the medial cuneate nucleus and moderate labelling of the gracilis and lateral cuneate nuclei occurred contralaterally to the injection site. A small numebr of medial cuneate and gracile neurons project to the ipsilateral thalamus. Projections from the solitary nucleus were always ipsialteral. The boundaries of individual subnuclei of the lateral sensory trigeminal complex in the rat have been redefined on the basis of cytological criteria; these are in good accord with the corresponding thalamic projection patterns.

Corticofugal pathways from areas of the cat auditory cortex to the sensory trigeminal nuclei and ventrobasal thalamic complex

The complex system of trigeminal nuclei receives somatic and visceral impulses from superficial and deep tissues of the animal's muzzle and transmits them to the nuclei of the other cranial nerves, the reticular formation, and the ventral complex of thalamic nuclei [i, 4, 6]. Corticofugal pathways running to the trigeminal nuclei have been studied mainly in relation to the sensomotor cortex [7]. The frontal, parietal and, to a lesser degree, the visual and auditory regions also have been shown to project to the sensory trigeminal nuclei, but from the available data it is impossible to judge the topical Organization of these connections, for extensive regions of the cortex, including many specific areas~ were destroyed during the investigation [4].

Responses of neurons in rostral and caudal trigeminal nuclei to tooth pulp stimulation

Using immobilized, lightly anesthetized cats, the responses of neurons in the nucleus principalis-subnucleus oralis and subnucleus caudalis regions of the sensory trigeminal complex were studied following electrical stimulation of the canine tooth pulp. Recording loci were verified histologically. Pulpal stimulation activated 122 cells in the rostral nuclei and 44 in the caudal one. Neurons in the two, spatially segregated, regions exhibited different, though overlapping distributions of response and receptive field properties. More specifically, the rostral region cells tended to have lower thresholds and to reach peak firing rates at lower stimulus intensities. Their peripheral fields were generally more restricted and more frequently homolateral. Following supra-maximal stimulation, they ordinarily had briefer initial spike latencies and their response bursts typically contained a greater number of spikes. These findings are consistent with the view that each of the regions operates in a different manner in the mediation of oro-facial pain.

The origin of trigeminal response components elicited by electrical stimulation of the tooth pulp of the cat

Field potentials were recorded in the trigeminal sensory complex in response to monopolar and bipolar stimulation of the tooth pulp to characterize the resultant activity of pulpal and extrapulpal origin. Monopolar and bipolar stimulation of pulpal elements resulted in identical responses. Using monopolar stimulation, cathodal thresholds were usually but not universally less than anodal thresholds. Spread of activity to include periodontal afferents occurred at intensities somewhat above that necessary for maximal pulp responses. No spread of activity was found either to gingival afferents using monopolar stimulation or to gingival or periodontal afferents using bipolar stimulation at any stimulus intensity.

The cortical projection of the orbital and proreate gyri to the sensory trigeminal nuclei in the cat. An experimental anatomical study

Following lesions of the orbital and proreate gyri the degeneration in the sensory trigeminal nuclei has been studied in Nauta and Fink and Heimer sections. The posterior part of the orbital gyrus and the entire proreate gyrus send fibres to the trigeminal nuclei. These projections differ in some respects from those from the sensorimotor cortical regions. The projection from the posterior part of the orbital gyrus is bilateral, the more sparse projection from the proreate gyrus is purely contralateral. Most of the fibres enter the nuclei from the spinal trigeminal tract. The cortical fibres from both gyri terminate mainly in a column-shaped area in the ventralmost part of the nucleus interpolaris, while the fibres from the sensorimotor cortical regions chiefly supply the nuclei principalis, oralis and caudalis as established in another study 37. The findings are discussed in the light of known data on the anatomical and functional organization of the sensory trigeminal complex.

Functional characteristics of single units in the spinal trigeminal nucleus of the pigeon.

193 cells of the spinal nucleus and tract of n.V (TTD) in pigeon were studied with microelectrode techniques. 155 cells could be activated by lightly touching discrete areas of the beak, palate or head surfaces. 38 cells were responsive only to displacement of the lower beak from its resting position. TTD tactile units were spontaneously active. Most adapted slowly to a maintained stimulus. Their receptive areas were primarily ipsilateral, some bilateral by virtue of distributing equally about the midline. Beak joint units responded either to mouth opening or closing or both, with an increase or a decrease in the background discharge rate. Somatotopic organization was evident only in the dorsoventral plane in which units with receptive areas innervated by maxillary and mandibular divisions of n.V lay dorsal to those innervated by the ophthalmic division. A comparison of TTD unit properties with those of the pigeon principal sensory nucleus is made as well as with the trigeminal sensory complex of mammalian forms. It is concluded that avian and mammalian trigeminal sensory complexes are fundamentally similar in their organization.

Hyperpolarizing influence of trigeminal nucleus caudalis on primary afferent preterminals in trigeminal nucleus oralis.

Hyperpolarizing influence of trigeminal nucleus caudalis on primary afferent preterminals in trigeminal nucleus oralis.C J Scibetta, and R B KingC J Scibetta, and R B KingPublished Online:01 Mar 1969https://doi.org/10.1152/jn.1969.32.2.229MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByCornea-Responsive Medullary Dorsal Horn Neurons: Modulation by Local Opioids and Projections to Thalamus and Brain StemHarumitsu Hirata, Shinichiro Takeshita, James W. Hu, and David A. Bereiter1 August 2000 | Journal of Neurophysiology, Vol. 84, No. 2Differential Effects of Morphine on Corneal-Responsive Neurons in Rostral Versus Caudal Regions of Spinal Trigeminal Nucleus in the RatIan D. Meng, James W. Hu, and David A. Bereiter1 May 1998 | Journal of Neurophysiology, Vol. 79, No. 5Encoding of Corneal Input in Two Distinct Regions of the Spinal Trigeminal Nucleus in the Rat: Cutaneous Receptive Field Properties, Responses to Thermal and Chemical Stimulation, Modulation by Diffuse Noxious Inhibitory Controls, and Projections to the Parabrachial AreaI. D. Meng, J. W. Hu, A. P. Benetti, and D. A. Bereiter1 January 1997 | Journal of Neurophysiology, Vol. 77, No. 1Golgi and immunocytochemical analysis of neurons in trigeminal subnucleus interpolaris: Correlations with cellular localization of enkephalinNeuroscience, Vol. 32, No. 2The rostral part of the trigeminal sensory complex is involved in orofacial nociceptionBrain Research, Vol. 448, No. 1Lesions of the Mid-Spinal trigeminal complex are effective in producing perioral thermal hypoalgesiaBrain Research, Vol. 382, No. 2Effects of trigeminal tractotomy on facial thermal nociception in the ratBrain Research, Vol. 333, No. 1Peripheral and central substrates involved in the Rostrad transmission of nociceptive informationPain, Vol. 13, No. 1Presynaptic excitability changes produced in brain stem endings of tooth pulp afferents by raphe and other central and peripheral influencesBrain Research, Vol. 218, No. 1-2Peripheral and central pathways in painPharmacology & Therapeutics, Vol. 14, No. 3Odorant responses in taste neurons of the rat NTSBrain Research, Vol. 135, No. 2Responses in the rostral medulla to electrical stimulation of an intranasal trigeminal nerve: Convergence of oral and nasal inputsNeuroscience Letters, Vol. 5, No. 6Response patterns to noxious and non-noxious stimuli in rostral trigeminal relay nucleiBrain Research, Vol. 97, No. 1Jamming spinal sensory input: Effects of anesthetic and analgesic drugs in the spinal cord dorsal hornPain, Vol. 1, No. 3Differences in the excitability of two populations of trigeminal primary afferent central terminalsBrain Research, Vol. 77, No. 2Trigeminal main sensory nucleus polymodal unit responses to noxious and non-noxious stimuliBrain Research, Vol. 72, No. 1Fine structural aspects of the synaptic organization of spinal trigeminal nucleus (pars interpolaris) of the catBrain Research, Vol. 25, No. 2Presynaptic inhibition of jaw-opening reflex by high threshold afferents from the masseter muscle of the catBrain Research, Vol. 23, No. 2Presynaptic hyperpolarization of fibers projecting to trigeminal brain stem and thalamic nucleiBrain Research, Vol. 22, No. 1 More from this issue > Volume 32Issue 2March 1969Pages 229-38 https://doi.org/10.1152/jn.1969.32.2.229PubMed4304624History Published online 1 March 1969 Published in print 1 March 1969 Metrics

Somatotopic organization of mechanoreceptor units in the trigeminal nuclear complex of the macaque

AbstractThe properties of neurons in the sensory trigeminal nuclear complex of macaque monkeys have been investigated by a systematic exploration of the principal sub‐divisions in an attempt to define somatotopic organization, modality representation, receptive field size and adaptive properties. Particular attention was paid to several discrepancies in the literature on the cat trigeminal complex. The results suggest that each cutaneous locus is represented by a rostro‐caudally oriented column of neurons possessing comparable properties and receptive field sizes at all levels examined in deeply anesthetized animals. A consistent somatotopic pattern with minor variations, was evident at all rostro‐caudal levels. Criteria for distinguishing “spinothalmic” and “lemniscal” neuron properties in appropriate portions of the sensory complex (inferred from human data) could not be identified. Neurons in adjacent structures may respond to crude stimuli and lack distinct receptive fields, but it is unlikely that these are related to an afferent “pain” pathway.

Thalamic afferents from the spinal cord and trigeminal nuclei. An experimental anatomical study in the rat.

AbstractDegeneration studies after making lesions involving the spino‐thalamic pathways indicate that the projection from any level of the cord to the ventrobasal complex differs from that of the medial lemniscus in that it is less dense and ends largely in the rostral one third in a topographical pattern. Additional projections from all levels of the cord end in the nuclei pretectalis anterior, centralis lateralis, medialis dorsalis and in the medial geniculate body pars medialis and dorsal part of the posterolateral complex. Fibers from the rostral few segments of the cord, possibly from the lateral cervical nucleus, end in addition in the caudal part of the ventrobasal complex and sparsely in the parafascicular‐centrum medianum complex and zona incerta. Heavy degeneration was found in all the brains in the brainstem reticular formation.The tritgeminal sensory nuclei project heavily to the dorsomedial cell band of the ventrobasal complex and sparsely to the neighboring part of the posterolateral complex. There is no evidence of a projection from any level of the trigeminal sensory complex to any part of the intralaminar nuclei.