Correlation of the main peripheral branches of the facial nerve with the cytoarchitectonic subdivisions of the facial nucleus in the guinea pig

Summary Correlation of the main peripheral branches of the facial nerve with morphological subdivisions of the facial nucleus was examined in the guinea pig by the retrograde horseradish peroxidase method. The facial nucleus of the guinea pig was divided cytoarchitectonically into the dorsolateral, lateral, intermediate, medio-intermediate, medial, and ventromedial divisions; the ventromedial division was further divided into the major, dorsal and lateral parts. Six main branches of the facial nerve were identified; the zygomatico-orbital, cervical, posterior auricular, anterior auricular, superior labial, and inferior labial branches. After applying HRP to the main branches of the facial nerve, the pattern of distribution of HRP-labelled neuronal cell bodies within the facial nucleus was examined: the dorsolateral division, dorsal part of the ventromedial division, major part of the ventromedial division, lateral part of the ventromedial division, or medial division contained the cell bodies of respectively the zygomatico-orbital, cervical, posterior auricular, anterior auricular, or superior labial branches, while each of the lateral, intermediate, and medio-intermediate divisions contained the cell bodies of both the superior labial and inferior labial branches.     

Topographical representation of peripheral branches of the facial nerve within the facial nucleus: A HRP study in the cat

Representation of peripheral branches of the facial nerve within the facial nucleus of the cat was examined by utilizing retrograde axonal transport of horseradish peroxidase (HRP), which was injected into groups of muscles supplied by each of the main peripheral branches of the facial nerve. The cervical branch was represented in the ventromedial division of the facial nucleus, the posterior auricular branch in the medial division, the temporal branch in the intermediate division, the zygomatico-orbital branch in the dorsal division, the superior labial branch in the lateral division and the inferior labial branch in the ventrolateral division.     

The facial nucleus of the rat: representation of facial muscles revealed by retrograde transport of horseradish peroxidase

The representation of facial muscle groups in the facial nucleus of rat was examined by retrograde transport of HRP. Motoneurons supplying muscle groups are arranged in longitudinal columns. Those supplying nasolabial muscles are located in the lateral and ventral intermediate segments, posterior auricular muscles in a medial column, platysma in an intermediate column; the lower lip and ocular muscles are in the ventral and dorsal segments respectively of the intermediate column. The posterior belly of the digastric muscle is supplied by motoneurons extending from the dorsal aspect of the facial nucleus to the caudal pole of the trigeminal motor nucleus.     

Topographical arrangement of hypoglossal motoneurons: an HRP study in the cat

Myotopical localization of hypoglossal motoneurons and representation of the main branches of the hypoglossal nerve within the hypoglossal nucleus were examined in the cat by the HRP method. The hypoglossal nucleus is divided cytoarchitectonically into the ventromedial and dorsolateral divisions; the medial and lateral branches of the hypoglossal nerve are represented respectively in the ventromedial and dorsolateral divisions. The genioglossus motoneurons are located in the ventrolateral part of the ventromedial division, and the geniohyoid motoneurons are in the most ventral part of the ventromedial division. The hypoglossus and styloglossus motoneurons are located in the lateral and dorsolateral parts of the dorsolateral division.     

Cells of origin of the branches of the facial nerve: A retrograde HRP study in the rabbit

The origin of different branches of the facial nerve in the rabbit was determined by using retrograde transport of HRP. Either the proximal stump of specific nerves was exposed to HRP after transection, or an injection of the tracer was made into particular muscles innervated by a branch of the facial nerve. A clear somatotopic pattern was observed. Those branches which innervate the rostral facial musculature arise from cells located in the lateral and intermediate portions of the nuclear complex. Orbital musculature is supplied by neurons in the dorsal portion of the complex, with the more rostral orbital muscles receiving input from more laterally located cells while the caudal orbital region receives innervation from more medial regions of the dorsal facial nucleus. The rostral portion of the ear also receives innervation from cells located in the dorsomedial part of the nucleus, but the caudal aspect of the ear is supplied exclusively by cells located in medial regions. The cervical platysma, the platysma of the lower jaw, and the deep muscles (i.e., digastric and stylohyoid) receive input from cells topographically arranged in the middle and ventral portions of the nuclear complex. It is proposed that the topographic relationship between the facial nucleus and branches of the facial nerve reflects the embryological derivation of the facial muscles. Those muscles that develop from the embryonic sphincter colli profundus layer are innervated by lateral and dorsomedial portions of the nuclear complex. The muscles derived from the embryonic platysma layer, including the deep musculature, receive their input from mid to ventral regions of the nuclear complex.     

Non-motoneurons in the facial and motor trigeminal nuclei projecting to the cerebellar flocculus in the cat

Summary The cerebellar projection from the facial and motor trigeminal nuclei was studied in the cat by means of retrograde axonal transport of wheat germ agglutinin-horseradish peroxidase and fluorescent tracers. The feline facial nucleus was cytoarchitectonically subdivided into ventromedial, ventrolateral, lateral, dorsal, intermediate and medial divisions (see Papez 1927), and the motor trigeminal nucleus into medial, ventral, intermediate, lateral and dorsal divisions. The neurons in the facial and motor trigeminal nuclei were classified as small (ovoid to round cells with a maximum diameter of the cell body of about 20 m) or large (polygonal to round cells with maximum diameter of about 40 m). After floccular injections of the wheat germ agglutininhorseradish peroxidase complex, retrogradely labelled cells were found throughout the facial nucleus, but especially in its medial and dorsal divisions. In the motor trigeminal nucleus, labelled neurons were found only in the ventral, intermediate and lateral divisions. Cases with tracer deposition (implants or injections) in other parts of the cerebellar cortex or nuclei were all negative. All facial and motor trigeminal neurons labelled after floccular injections were smaller than the neurons labelled after injections in the facial mimic and masticatory muscles, and only single-labelled neurons were found following floccular injections of Fluoro-Gold and muscular injections of rhodamine-B-isothiocyanate in the same animals. These observations strongly suggest that the neurons in the facial and motor trigeminal nuclei which project to flocculus are of the non-motoneuron type.     

Distribution of facial motoneurons innervating the common facial muscles of the rabbit and rat

The distribution of the facial neurons that innervate several facial muscles was determined in the rabbit and the rat by examining the retrograde transport of horseradish peroxidase (HRP). The target muscles were musculus levator nasolabialis, m. levator labii superioris, m. zygomaticus, and m. buccinator pars buccalis, as well as m. parietoauricularis and m. depressor anguli oris in the rabbit and m. levator auricularis posterioris in the rat. Localization of the retrogradely labeled neurons within the ipsilateral facial nucleus was confirmed for all facial muscles examined. Our results showed that m. levator nasolabialis was innervated by neurons located in the dorsal subnucleus, while the motoneurons innervating m. buccinator pars buccalis were distributed within the dorsal part of the intermediate subnucleus of the facial nucleus in the both species. Localization of the labeled motoneurons innervating m. zygomaticus and m. levator labii superioris showed the difference in the distribution within the facial nucleus among the species. Neurons innervating m. parietoauricularis and m. levator auricularis posterioris were localized in somewhat different subregions of the medial subnucleus in these species. M. depressor anguli oris was innervated by the neurons distributed within the intermediate subnucleus of the facial nucleus in the rabbit. Thus, our findings revealed that there is species-specific motor innervation pattern in rabbits and rats, despite several movement of the face is supplied by the homologous facial muscles.     

Innervation of the canine thoracolumbar vertebral column

The pattern of innervation of the caudal thoracic and cranial lumbar vertebral column of the dog is described. Frozen sections stained with Schofield's silver impregnation method show that the dorsal longitudinal ligament is profusely innervated, while the anulus fibrosus contains a few nerves limited to its outermost layers; no nerves are present in the nucleus pulposus. Following injection of horseradish peroxidase (HRP) into the anulus fibrosus of the thoracolumbar intervertebral disc and subsequent removal and staining of dorsal root ganglia, the reaction product is found in ganglia as far as two segments cranially as well as caudally, demonstrating that the disc is innervated by nerves arising from several spinal cord segments. A meningeal ramus, which innervates the discs of man, could not be found by gross dissection. Dissections show each vertebral articular facet innervated by the medial branches of two contiguous spinal nerves, a pattern further confirmed by injections of HRP into facet joints with subsequent staining of dorsal root ganglia. The dorsal rami of spinal nerves often divide into medial, intermediate, and lateral branches rather than the traditionally described division into only medial and lateral branches.     

The facial artery of the common marmoset (Callithrix jacchus)

The facial artery and its ramifications in 7 adult common marmosets (Callithrix jacchus) were studied by the plastic injection method. The findings obtained are discussed in comparison with those for other primates. In the submandibular region, the facial artery arose from the external carotid artery at the height of the atlas via the linguofacial trunk on 10 of the total of 14 sides examined and independently on the other 4 sides. This common trunk always gave rise to the superior thyroid artery. The facial artery passed anterolaterally between the styloglossus muscle and the intermediate tendon of the digastricus muscle, giving off the styloglossal and the submandibular glandular branches, and anteroinferiorly medial to the pterygoideus medialis muscle. In a position anterior to this muscle, the submental artery and masseteric branch were derived. The submental artery gave off the medial pterygoid, the digastric, the cutaneous, the sublingual glandular and the mylohyoid branches, and then continued up to the median line, where it terminated to supply the genioglossus muscle. In the facial region, the facial artery passed anterosuperiorly along the anterior margin of the masseter muscle on 12 sides and away from it forwards on 2 sides, giving off the premasseteric branch in one of these 2 sides. It gave rise to the cutaneous, the buccal and the buccinator branches, the inferior labial artery and the communicating branch with the zygomatic artery. It terminated to divide into the superior labial and the naris lateral arteries, although the latter was lacking on 4 sides. The inferior labial artery gave off the mandibular marginal, the inferior labial marginal and the inferior labial glandular branches and terminated to anastomose with the mental artery. The superior labial artery divided into the superficial and deep branches, each of which continued as a nasal septal branch. The facial artery of the common marmoset usually ascended along the anterior margin of the masseter muscle and did not reach the medial angle of the eye.     

Evidence that the medial amygdala projects to the anterior/ventromedial hypothalamic nuclei to inhibit maternal behavior in rats

The maternal behaviors shown by a rat that has given birth are not shown by a virgin female rat when she is first presented with young. This absence of maternal behavior in virgins has been attributed to the activity of a neural circuit that inhibits maternal behavior in nulliparae. The medial amygdala and regions of the medial hypothalamus such as the anterior and ventromedial hypothalamic nuclei have previously been shown to inhibit maternal behavior, in that lesions to these regions promote maternal responding. Furthermore, we have recently shown that these and other regions, such as the principal bed nucleus of the stria terminalis, the ventral lateral septum, and the dorsal premammillary nucleus, show higher pup-induced Fos-immunoreactivity in non-maternal rats exposed to pups than during the performance of maternal behavior, indicating that they too could be involved in preventing maternal responsiveness. The current study tested whether the medial amygdala projects to the anterior/ventromedial hypothalamic nuclei in a neural circuit that inhibits maternal behavior, as well as to see what other brain regions could participate in this circuit.Bilateral excitotoxic lesions of the medial amygdala, or of the anterior/ventromedial hypothalamic nuclei, promoted maternal behavior. Unilateral medial amygdala lesions caused a reduction of pup-induced Fos-immunoreactivity in the anterior/ventromedial hypothalamic nuclei in non-maternal rats ipsilateral to the lesion, as well as in the principal bed nucleus of the stria terminalis, ventral lateral septum, and dorsal premammillary nucleus. Finally, unilateral medial amygdala lesions paired with contralateral anterior/ventromedial hypothalamic nuclei lesions promoted maternal behavior, although ipsilateral lesion placements were also effective.Together, these results indicate that the medial amygdala projects to the anterior/ventromedial hypothalamic nuclei in a neural circuit that inhibits maternal behavior, and that the principal bed nucleus of the stria terminalis, ventral lateral septum, and dorsal premammillary nucleus could also be involved in this circuit.     

Cytoarchitecture and musculotopic organization of the facial motor nucleus in Cebus apella monkey

The architecture and musculotopic organization of the facial motor nucleus in the Cebus apella monkey (a New World primate) were investigated using histological techniques and a multiple labelling strategy, in which horseradish peroxidase‐conjugated neuroanatomical tracers (CTB‐HRP and WGA‐HRP) and fluorescent tracers were injected into individual facial muscles. The facial motor nucleus was formed by multipolar motoneurons and had an ovoid shape, with its rostrocaudal axis measuring on average 1875 µm. We divided the nucleus into four different subnuclei: medial, intermediate, dorsal and lateral. Retrograde labelling patterns revealed that individual muscles were innervated by longitudinal functional columns of motoneurons. The columns of the orbicularis oculi, zygomaticus, orbicularis oris, auricularis superior, buccinator and platysma muscles were located in the dorsal, intermediate, lateral, medial, lateral and intermediate subnuclei, respectively. However, the motoneuron columns of the levator labii superioris alaeque nasi muscle and frontalis muscle could not be associated with a specific subnucleus. The present results confirm previous studies regarding the musculotopic organization of the facial motor nucleus. However, we observed some particularities in terms of the relative size of each column in C. apella, which might be related to the functional and behavioral importance of each muscle in the particular context of this primate.     

Afferent connections of dorsal and ventral agranular insular cortex in the hamsterMesocricetus auratus

The agranular insular cortex is transitional in location and structure between the ventrally adjacent olfactory allocortex primutivus and dorsally adjacent sensory-motor isocortex. Its ventral anterior division receives major afferent projections from olfactory areas of the limbic system (posterior primary olfactory cortex, posterolateral cortical amygdaloid nucleus and lateral entorhinal cortex) while its dorsal anterior division does so from non-olfactory limbic areas (lateral and basolateral amygdaloid nuclei).The medial segment of the mediodorsal thalamic nucleus projects to both the ventral and dorsal divisions of the agranular insular cortex, to the former from its anterior portion and to the latter from its posterior portion. Other thalamic inputs to the two divisions arise from the gelatinosus, central medial, rhomboid and parafascicular nuclei. The dorsal division, but not the ventral division, receives input from neurons in the lateral hypothalamus and posterior hypothalamus.The medial frontal cortex projects topographically and bilaterally upon both ventral and dorsal anterior insular cortex, to the former from the ventrally located medial orbital and infralimbic areas, to the latter from the dorsally-located anterior cingulate and medial precentral areas, and to both from the intermediately located prelimbic area. Similarly, the ipsilateral posterior agranular insular cortex and perirhinal cortex project in a topographic manner upon the two divisions of the agranular insular cortex.Commissural input to both divisions originates from pyramidal neurons in the respective contralateral homotopical cortical area. In each case, pyramidal neurons in layer V contribute 90% of this projection and 10% arises from layer III pyramidals.In the brainstem, the dorsal raphe nucleus projects to the ventral and dorsal divisions of the agranular insular cortex and the parabrachial nucleus projects to the dorsal division.Based on their cytoarchitecture, pattern of afferent connections and known functional properties, we consider the ventral and dorsal divisions of the agranular insular cortex to be, respectively, periallocortical and proisocortical portions of the limbic cortex.     

大白鼠脚间核的传入性联系

本实验应用微量注射和离子透入法经三种不同入路,将HRP输入大鼠脚间核内,追踪脚间核的传入性联系。三种不同进针方向,共同出现标记神经元的核团除了缰内侧核、缰外侧核、中缝背核、中央上核、被盖背核、被盖背外侧核、导水管周围灰质外侧与腹外侧区和蓝斑以外,尚有Broca氏斜角带核和伏隔核。组内侧核和脚间核的联系存在着明显的局部定位关系,即双侧缰内侧核内侧投射至脚间核中部的腹侧和腹外侧;双侧缰内侧核外侧投射至脚间核中部的背侧;同侧缰内侧核投射至脚间核中部的外侧;双侧缰内侧核纤维并不投射至脚间核的吻端和尾端。本研究还发现其它核团对脚间核的投射也存在一定的局部定位关系,如缰外侧核、被盖背核腹内侧和被盖背外侧核均投射到脚间核的尾侧;伏隔核尾端也有投射纤维至脚间核。     

辣根过氧化物酶逆行追踪风池穴的神经径路

目的：研究风池穴的神经径路。方法：针灸组大鼠对风池穴行透刺法后,将HRP从一侧风池穴注入对侧风池穴;对照组不行针灸,直接将HRP从一侧风池穴注入对侧风池穴。于不同时间点,对脑、脊髓及神经节行连续冰冻切片。结果：针灸后第1天,HRP阳性神经元出现于双侧第1～4颈神经节及其对应的颈髓前角、面神经核内侧部和副面神经核。随着存活时间的延长,阳性神经元密度减少,颜色变淡。对照组上述部位的HRP阳性神经元的面密度等较针灸组小。结论：风池穴可能通过面神经的耳后支、第2～3颈神经前支分别与面神经核群及副面神经核、颈髓和延髓前角神经元相联系而发挥其功能。     

Relation of the parabigeminal nucleus to the superior colliculus and dorsal lateral geniculate nucleus in the hooded rat

Summary The retino-recipient layers of the superior colliculus project predominantly to the dorsal and ventral divisions of the ipsilateral parabigeminal nucleus, while receiving an input chiefly from the medial division of the contralateral nucleus. A variety of retrograde tracing techniques was used to confirm that there is a projection from the medial division of the parabigeminal nucleus to the contralateral dorsal lateral geniculate nucleus in normal adult hooded rats. Some parabigeminal cells branch to supply both dorsal lateral geniculate nucleus and retino-recipient layers of the superior colliculus.     

Motor nuclear representation of masticatory muscles in the rat

Representation of the masticatory muscles within the motor trigeminal nucleus was studied in rats by the horseradish peroxidase (HRP) method and the antidromic field potential method. The motor trigeminal nucleus of the rat could be divided cytoarchitecturally into a dorsolateral and a ventromedial division. Within the dorsolateral division, the temporal muscle was represented dorsomedially, the masseter muscle dorsolaterally and laterally, and the lateral and medial pterygoid muscles ventrolaterally. Within the ventromedial division, the anterior digastric muscle was represented dorsomedially and the mylohyoid muscle ventrolaterally. Distribution of antidromic field potentials evoked by stimulation of the mylohyoid and masseteric nerves coincided with the results from the HRP investigation.     

Re-examination of the topographical distribution of motoneurons innervating the digastric muscle in the rabbit and guinea pig.

The topographical distribution of motoneurons innervating the digastric muscle in the rabbit and guinea pig was re-examined by the retrograde tracing method of HRP (horseradish peroxidase). Motoneurons innervating the anterior belly of the digastric muscle of the rabbit and guinea pig constituted a longitudinal cell column in the ventromedial part of the motor nucleus of the trigeminal nerve. Motoneurons innervating the posterior belly of the digastric muscle were localized in the accessory facial nucleus. No motoneurons supplying the digastric muscle were found within the main facial nucleus.     

Direct projections of the hypothalamic nuclei to the thalamic mediodorsal nucleus in the cat

Direct projections of the hypothalamic nuclei to the thalamic mediodorsal nucleus (MD) were studied using retrograde and anterograde transport of horseradish peroxidase (HRP) and wheat germ agglutinin (WGA)-HRP. HRP and WGA-HRP were injected into the MD, thalamic paraventricular, lateral habenular and hypothalamic nuclei. The results indicate that the MD, particularly its medial part, receives a moderate amount of hypothalamic afferents, and that most of these afferents originate in the medial part of the lateral hypothalamic nucleus at anterior levels, while a limited number are derived from the dorsal, dorsomedial, ventromedial and anterior hypothalamic and lateral preoptic nuclei.     

Primary afferent fibers in the glossopharyngeal nerve terminate in the dorsal division of the principal sensory trigeminal nucleus: an HRP study in the cat

After applying horseradish peroxidase to the central cut end of the pharyngo-esophageal branch of the glossopharyngeal nerve in the cat, axon terminals labeled transganglionically with the enzyme were found ipsilaterally in the dorsomedial tip regions and ventromedial border regions of the dorsal division of the principal sensory trigeminal nucleus (dorsal Vp), as well as in the solitary, spinal trigeminal and medial cuneate nuclei. The area of termination in the dorsal Vp extended about 200 micron rostrocaudally in the caudal two-thirds of the dorsal Vp.     

The facial artery of the lion (Panthera leo)

An investigation was made of the facial artery in 3 heads of the lion (Panthera s. Felis leo) in the possession of the authors' department. The heads were injected with acryl plastic via the common carotid artery and were examined from the standpoint of the comparative anatomy. Five sides of these 3 heads were prepared to vascular corrosion casts and the remaining side to a dessection specimen preserved in formalin solution. The facial artery of the lion arose independently from the anteroinferior wall of the external carotid artery between the styloglossus and digastricus muscles and between the origins of the lingual and the posterior auricular arteries at a position where the external carotid curved laterally anterior to the tympanic bulla. The facial artery gave rise to the mandibular glandular branch posterosuperiorly immediately after its origin and passed forwards medial to the insertion of the masseter along the superior margin of the digastricus and bent anteroinferiorly giving off the sublingual glandular branch after the divergence of a thick, masseteric branch. The facial artery reached the posterior margin of the mylohyoideus muscle, where it gave rise to the submental artery anteroinferiorly from its inferior wall. The submental artery passed forwards along the inferior margin of the mandible, giving off the digastric and the mylohyoid branches, up to the intermandibular synchondrosis, where it anastomosed with the opposite fellow after giving off the genioglossal branch. The main stream of the facial artery, after giving off the submental artery, reached the face through the facial vascular notch of the mandible. The facial artery passed anterosuperiorly along the anterior margin of the masseter muscle, giving off the buccal, the cutaneous and the mandibular marginal branches, up to a position posterior to the oral angle, where it terminated to the inferior labial and the posterior superior labial arteries. Similarities between the lion and the cat were found in terms of both the origin and ramifications. However, the inferior labial artery was more developed than that of the cat, whereas the peripheral ramifications of the submental artery were underdeveloped and supplemented by the lingual artery.