During the first 2 weeks of postnatal development, numerous GATA3-expressing cells were found in the intergeniculate leaf, ventral lateral geniculate nucleus, pretectal nucleus, nucleus of the posterior Commissure, superior colliculus, Inferior Colliculus, periaqueductal grey, substantia nigra and raphe nuclei. 
A lipophilic carbocyanine dye, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI), was placed in the dorsal tegmental Commissure of Probst to label decussating DNLL axons that end in the central nucleus of the contralateral IC.
The Commissure of the Inferior Colliculus is significant as the final point of interconnection between homologous structures on the two sides of the auditory pathway at the subcortical level. Using rats, we injected biotinylated dextran amine into the Inferior Colliculus on one side to retrogradely label cells projecting through the Commissure from the contralateral Inferior Colliculus.
All animals were killed at P12 and glass pins coated with carbocyanine dye, DiI (1,1'-dioctodecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate), subsequently were placed in the Commissure of Probst to label the crossed projections from both DNLLs.
When the inhibitory receptors were not pharmacologically blocked, taurine reversibly reduced the postsynaptic currents/potentials evoked by electrically stimulating the Commissure of the Inferior Colliculus or the ipsilateral lateral lemniscus.
In other regions, immunoreactive cells are moderately stained (i.e., magnocellular nucleus of the posterior Commissure, amygdaloid nucleus, interpeduncular nucleus, lateral periaqueductal gray) or weakly stained (i.e., vascular organ of the lamina terminalis, hippocampus, Inferior Colliculus, reticular nucleus).
These structures included the neocortex, hippocampus, amygdala, olfactory bulbs, basal forebrain and septum, caudate-putamen, globus pallidus, thalamus, hypothalamus, central gray, superior colliculi, inferior colliculi, the rest of midbrain, cerebellum, brainstem, corpus callosum/external capsule, internal capsule, anterior Commissure, fimbria, and ventricles.
The right and left inferior colliculi (ICs) in the auditory midbrain are connected to one another by a bundle of fibres, the Commissure of the IC. Previous studies show that this commissural projection connects corresponding frequency regions in the two sides and originates mainly from excitatory neurons, although some studies suggest a smaller number of GABAergic inhibitory neurons may also project via the Commissure. Although the Commissure of the IC is a major pathway connecting the most important nuclei of the auditory tectum, little is known about its functional significance. The results suggest that one function of the Commissure of the IC may be to modulate the response gain of IC neurons to acoustic stimulation..
Lateral lemniscal and Commissure of the IC-evoked inhibitory postsynaptic currents (IPSCs) were recorded in an IC brain slice preparation using whole-cell and gramicidin perforated-patch electrodes in the presence of kynurenic acid.
Severed axons of the Inferior Colliculus (IC) Commissure can regenerate across a lesion in organotypic cultures from postnatal day (P) 6 gerbils, but this regenerative capacity is lost by P12 (Hafidi et al. To determine whether this age-dependent change in regenerative capacity can develop in organotypic cultures, IC slices with an intact Commissure were obtained from P6 animals, grown in vitro for 6 days, and then lesioned at the Commissure.
Preoptic structures (suprachiasmatic and preoptic nuclei) projected mainly to the anteromedial tectal zone, whereas thalamic (ventral and dorsal) and pretectal (central, superficial, and posterior Commissure) nuclei projected to all divisions of the tectum.
The Commissure of the Inferior Colliculus (CoIC) interconnects corresponding frequency-band laminae in the two inferior colliculi (ICs). Following blockade of the Commissure, 10 of 12 neurons tested exhibited an increase or a decrease in their FRAs. From our observation that FRAs contract following Commissure block, we infer that the Commissure contains excitatory fibres. The expansion of response areas in other cases, however, suggests that the Commissure also contains inhibitory fibres, or that its effects are mediated by disynaptic as well as monosynaptic circuits.
One to five days after bilateral cochlear ablation, the amplitude of evoked excitatory postsynaptic currents (EPSC) was measured with whole-cell voltage-clamp recordings in an Inferior Colliculus (IC) brain slice preparation in response to electrical stimulation of the ipsilateral lateral lemniscus (LL) or the Commissure of the Inferior Colliculus (CIC).
Rat pups were reared to P12, at which time glass pins coated with 1, 1'-dioctodecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate were placed in fixed tissue in the Commissure of Probst where DNLL fibers cross the midline.
The width, area and rise time of excitatory postsynaptic potentials (EPSPs) evoked by stimulation in the Commissure of IC were significantly elevated during ETX.
Whole-cell and gramicidin-perforated patch recordings were obtained from Inferior Colliculus neurons, and IPSCs were evoked by stimulation of the Commissure of the Inferior Colliculus (CIC) or the ipsilateral lateral lemniscus (LL) in the presence of kynurenic acid.
Dye-coated pins were positioned in paraformaldehyde-fixed brains either unilaterally in DNLL (embryonic cases), or in the Commissure of Probst where DNLL fibers cross the midline (postnatal cases).
Electrical stimulation of the IC Commissure (CoIC) elicited only inhibitory postsynaptic potentials (IPSPs) (10% of cells), only excitatory postsynaptic potentials (EPSPs) (51%), or both (38%).
Therefore, axonal regeneration was assessed following complete transection of the Commissure in AP5/CNQX-treated IC cultures from P12 animals. These data show that neuron survival is not sufficient to permit axon regeneration at P12, and suggest that P12 lesion sites manufacture a prohibitive substrate since process outgrowth is blocked specifically at the Commissure transection..
The model includes ascending connections from both lateral and medial superior olives (LSO and MSO) as well connections from interneurons in the DNLL and connections from the contralateral DNLL through the Commissure of Probst. In addition, we examine the effects of the MSO and the Commissure of Probst on DNLL output.
Binaural evoked responses were recorded with glass micropipettes from the central nucleus of the rat's Inferior Colliculus (ICC) before and after transection of the Commissure of Probst (CP) with a microsurgical knife.
NTT4 is detected beginning at E18 in various parts of the rat brain, including the cerebral cortex, fimbria hippocampi, fornix, lateral lemniscus, anterior Commissure, and spinal cord.
A total of 40 neurons from of the central nucleus of the mouse Inferior Colliculus (IC) were recorded intracellularly from brain slices to determine input properties by electrical stimulation of the ipsilateral lateral lemniscus (LL), Commissure of Probst (CP), and Commissure of the IC (CoIC) together with cellular morphology (in 25 neurons) by biocytin injection and staining. Axon collaterals of a given neuron often ran in several directions to provide multiple input to adjacent isofrequency laminae, the lateral nucleus of the IC, the brachium of the IC, the LL, the CP, and the IC Commissure.
To evaluate the contribution made to gerbil ICC neuron physiology by two major afferent pathways, we examined the synaptic responses evoked by direct stimulation of the Commissure of the Inferior Colliculus (CIC) and the ipsilateral lateral lemniscus (LL).
IR in neuronal cell bodies for PKC isoforms alpha, beta, gamma, and epsilon was densest in the olfactory bulb, hippocampus, shell of the Inferior Colliculus, pons, cerebral, piriform, and cerebellar cortex, whereas axonal staining was prominent in the brainstem, internal capsule, corpus callosum, anterior Commissure, fornix and olfactory tract.
Neurons in ICx and ICd, but not ICc, had synaptic responses to stimulation of the collicular Commissure (CoIC).
Clustering of intensely positive neurons was observed in discrete areas including the main and accessory olfactory bulbs, the islands of Calleja, the amygdala, the paraventricular nucleus of the thalamus, several hypothalamic nuclei, the lateral geniculate nucleus, the magnocellular nucleus of the posterior Commissure, the superior and inferior colliculi, the laterodorsal and pedunculopontine tegmental nuclei, the nucleus of the trapezoid body, the nucleus of the solitary tract and the cerebellum.
A third group of cadherin-8-positive gray matter structures has functional connections with the cerebellum (superior colliculus, anterior pretectal nucleus, red nucleus, nucleus of posterior Commissure, inferior olive, pontine, pontine reticular, and vestibular nuclei).
Stronger projections originate in the lateral preoptic area, the zona incerta, the nucleus of the posterior Commissure and some other thalamic areas, the lateral substantia nigra, the deep layers of the superior colliculus, the dorsal and lateral central gray, the deep mesencephalic nucleus, the paralemniscal zone, the intercollicular nucleus, the external cortex of the Inferior Colliculus, the oral and caudal pontine reticular nucleus, the deep cerebellar nuclei, the gigantocellular and lateral paragigantocellular reticular nuclei, the prepositus hypoglossal nucleus, the spinal trigeminal nuclei, and the intermediate layers of the spinal cord. Moderate projections were seen to diencephalic reticular areas, the zona incerta, the nucleus of the posterior Commissure, and to various other thalamic areas.
CB immunoreactivity was high only in the nucleus of the Commissure (NCO); counts revealed a 22.3% decrease in the number of CB+ cells in old CBA mice and a 25.1% decrease in old C57 mice.
During hypoxia LCMRglc were unchanged in the genu of the corpus callosum and the anterior Commissure and decreased in the cerebellar white matter.
Beginning in week 22, there is development of commissural axons (dorsal Commissure of the lateral lemniscus and Commissure of the Inferior Colliculus) and descending projections (descending collicular axons and olivocochlear bundle).
The ability of rats to localize sounds in space was determined before and after cutting of the Commissure of Probst. The Commissure of Probst was transected at its midline decussation with a microknife inserted into the brain according to stereotaxic coordinates. Six animals were tested after extensive lesions that destroyed all of the Commissure of Probst fibers. An additional animal was tested after a smaller lesion that destroyed most of the Commissure of Probst but left some fibers intact. Three control animals were tested before and after surgical intervention that did not involve the Commissure of Probst. Ninety to 95% of the contralaterally projecting neurons in the DNLL disappeared within 7 wk after transection of the Commissure of Probst. No labeled neurons were seen in the contralateral DNLL in cases with complete transection of the Commissure of Probst. This result confirmed that the transection of the Commissure of Probst was successful and that projections to other auditory structures remained intact. Transection of the Commissure of Probst produced marked deficits in midline sound localization. The mean minimum audible angle was elevated 22.1 degrees after destruction of the Commissure of Probst compared with a shift of only 2.0 degrees in control animals..
Following the injection of biocytin, in the ascending projections, labeled terminals were seen mainly in the caudal portion of the nucleus of the optic tract, the nucleus of the posterior Commissure, the posterior pretectal nucleus, the olivary pretectal nucleus, the mesencephalic reticular formation at the level of the oculomotor nucleus, and the lateral posterior nucleus of the thalamus on the ipsilateral side. Following the injection of muscimol into the pretectum, including the nucleus of the optic tract, the posterior pretectal nucleus, and the nucleus of the posterior Commissure, accommodative responses evoked by microstimulation of the superior colliculus were reduced to 33-55% of the value before the injections. These findings suggest that the accommodation area in the superior colliculus projects to the oculomotor nucleus through the ipsilateral pretectal area, especially the nucleus of the optic tract, the nucleus of posterior Commissure, and the posterior pretectal nucleus, and also projects to the pupilloconstriction area (the olivary pretectal nucleus), the vergence-related area (the mesencephalic reticular formation), and the active visual fixation-related area (the nucleus raphe interpositus)..
Three projection systems of the NIC were distinguished: commissural (through the posterior Commissure), descending, and ascending. The posterior Commissure system gave rise to dense terminal fields in the contralateral NIC, the oculomotor nucleus, and the trochlear nucleus.
Correlation of myelin-stained or cryotomic sections of human brain with inversion-recovery MR images can display the cerebral Commissures as white-matter tracts (in hypersignal on MRI), crossing the mid-line. MRI shows routinely in three orthogonal planes a) the corpus callosum stretched above the supra-tentorial ventricles, it's four portions (rostrum, genu, body and splenium) and connections with the Deep Grey Nuclei b) the fornix, intralimbic Commissure joining anteriorly the mammillary bodies (through it's columns) to the alveus posteriorly and inferiorly (via it's two crura), arcing around the thalamus and lying over the hippocampus and the dentate gyrus as shown on the frontal sections c) the anterior Commissure, white-matter tract connecting the two temporal lobes. In axial view, the anterior Commissure has the shape of bicycle handlebars, coursing posteriorly, inferiorly and laterally behind the head of the caudate nucleus and passes into the lateral nucleus of the globus pallidus into the inferior and middle temporal gyri. Because the anterior Commissure is easily recognisable in all planes, it's appears to be a important landmark for identification of the lateral and medial nuclei of the globus pallidus on axial and sagittal planes d) at least, the posterior Commissure, anterior margin of the pineal region, closely related to the superior colliculi, acquire a major importance in the AC-PC line delineation becoming a reference landmark for stereotatical procedures..
By the 29th week, definitive myelination is present in all auditory pathways, including the proximal end of the cochlear nerve, trapezoid body, lateral lemniscus, dorsal Commissure of the lemniscus, Commissure of the Inferior Colliculus and brachium of the Inferior Colliculus.
The oblique and perpendicular systems are fibres of passage projecting to the Commissure and brachium of the IC, respectively..
(5) Stimulation of the Commissure of the Inferior Colliculus caused synaptic paired pulse inhibition in normal ICd neurons, but paired pulse facilitation was always observed in GEPR neurons. (6) In GEPR, a large epileptiform depolarizing event could be elicited by strong electrical stimulation of the Commissure of the Inferior Colliculus.
NADPH-d positive perikarya were found in the dorsal and external cortices of the Inferior Colliculus and in the intercollicular Commissure.
As described previously in guinea pig (Smith, 1986) and rat (Pierson et al., 1989), a large NMDA-mediated depolarizing event (paroxysmal depolarizing shift, or PDS) could be elicited by shocking the Commissure of the IC in the presence of picrotoxin or bicuculline, NMDA, 4-aminopyridine, or in 0 Mg2+ Ringer's. The main axons project laterally along the circumference of the IC or medially into the Commissure separating the collicular hemispheres..
On the other hand, CaM mRNA was colocalized with the AC and GC mRNA, but its distribution was more abundant and specific for neuronal cells, since there was little hybridization signal with CaM probe in neuronal fiber regions such as the corpus callosum and the anterior Commissure.
In the forebrain, the c-kit mRNA signals were detected in the olfactory bulb, the caudate-putamen, throughout the superficial cortex, the accumbens nucleus, the nucleus of vertical limb diagonal band, the bed nucleus of anterior Commissure, Ammon's horn, the entopeduncular nucleus, the subthalamic nucleus, the dorsal raphe nucleus, the parasubiculum, the presubiculum, the ventricular nucleus of lateral lemniscus, and the entorhinal cortex.
Conventional retrograde and orthograde axonal transport tract-tracing techniques were used in cats to explore the auditory decussations and Commissures in the upper pons and midbrain. Three of the 8 decussations (from the dorsal nucleus of the lateral lemniscus to the contralateral dorsal nucleus of the lateral lemniscus, from the dorsal nucleus of the lateral lemniscus to the contralateral Inferior Colliculus, from the sagulum to the contralateral sagulum) reach their targets via the Commissure of Probst. The remaining 5 decussations (from the Inferior Colliculus to the contralateral Inferior Colliculus or medial geniculate, from the intermediate nucleus of the lateral lemniscus to the contralateral medial geniculate, from the sagulum to the contralateral Inferior Colliculus or medial geniculate) reach their targets via the Commissure of the Inferior Colliculus. The results also suggest that the Commissure of Probst is not a general avenue for decussating auditory fibers of the lateral lemniscus but is instead a specific avenue only for fibers from the dorsal nucleus of the lateral lemniscus and sagulum.
Associated anomalies include hydrocephalus, fusion of the inferior colliculi, deficiency or absence of the septum pellucidum, and hypoplasia of the anterior Commissure.
In the midbrain, labeled terminals were found in the rostral interstitial nucleus of the medial longitudinal fasciculus, a medial part of Forel's H-field, the periaqueductal gray, the posterior Commissure nucleus, and the superior colliculus of the contralateral side.
The periventricular bundle bifurcates at the level of the posterior Commissure to form hypothalamic and thalamic components which distribute to the anterior pretectal region, lateral habenulae, and nuclei of the posterior Commissure, the majority of the intralaminar and midline thalamic nuclei, and to almost all of the hypothalamus.
They appeared also in the central mesencephalic reticular formation (cMRF), the periaqueductal gray (PAG), the posterior Commissure nucleus, and the superior colliculus.
These areas include zona incerta, nucleus of the posterior Commissure, anterior and posterior pretectal nuclei, nucleus of the optic tract, superior colliculus, cuneiform nucleus, subcuneiform area, substantia nigra pars reticulata and pars lateralis, periparabigeminal area, external nucleus of the Inferior Colliculus, the area ventral to the external nucleus of the Inferior Colliculus, mesencephalic reticular formation, dorsal and ventral nuclei of the lateral lemniscus, and the perihypoglossal nucleus.
Inputs to LDTg were found from frontal cortex, diagonal band, preoptic areas, lateral hypothalamus, lateral mamillary nucleus, lateral habenula; the interpeduncular nucleus, ventral tegmental area, substantia nigra and retrorubral fields; the medial terminal nucleus, interstitial nucleus, supraoculomotor central grey, medial pretectum, nucleus of the posterior Commissure, paramedian pontine reticular formation, paraabducens and paratrochlear region; the parabrachial nuclei and nucleus of the tractus solitarius. A number of brainstem structures apparently associated with visual functions were also innervated, mainly the superior colliculus, medial pretectum, medial terminal nucleus, paramedian pontine reticular formation, inferior olive, supraoculomotor, paraabducens and supragenual regions, prepositus hypoglossi and nucleus of the posterior Commissure.
The anterior Commissure appears in stage 23. The dentate nucleus, as well as the inferior and superior cerebellar peduncles and some of the cerebellar Commissures, are present.
However, in the mouse neuronal labelling was observed throughout the neural axis, including cellular labelling in the bed nucleus of the anterior Commissure, the median preoptic nucleus, the bed nucleus of the stria terminalis, the periventricular region, the anterior parvicellular subnucleus of the paraventricular nucleus, around the dorsomedial hypothalamic nucleus (pars compacta), the subincertal region, the arcuate nucleus, the anterior cortical nucleus of the amygdala, the suprageniculate nucleus, the lateral lemniscal nuclei, the lateraldorsal and lateralventral central gray, the posterior aspects of the commissural and marginal nuclei of the Inferior Colliculus, the paragenule nucleus, the A-5 region, the area postrema, the ventromedial nucleus of the solitary tract, area X, the spinal trigeminal nucleus (pars zonale), and superficial laminae of the spinal cord.
Other afferents, which were thought to have been labeled through spread of HRP into the medial longitudinal fasciculus (MLF), adjacent paramedian pontine reticular formation, or uptake by transected fibers descending to the inferior olive, included the nucleus of Darkschewitsch, interstitial nucleus of Cajal, zona incerta, prerubral fields of Forel, deep superior colliculus, nucleus of the posterior Commissure, nucleus cuneiformis, ventral periaqueductal gray, vestibular complex, perihypoglossal complex, and deep cerebellar nuclei.
However, mean LCGU was significantly depressed in olfactory cortex, temporal cortex, olfactory tubercle, amygdala, caudate/putaman, Inferior Colliculus, medial geniculate, anterior Commissure, and corpus callosum, and the functional groups that make up the olfactory and auditory systems.
The dimesencephalic borderline passes through the commissural fibres in the roof: the rostral part of the Commissure is the posterior Commissure, the caudal part, the Commissure of the superior colliculi.
The earliest degeneration was observed at day 1 in the intermediate and ventral divisions of the lateral septal nucleus, followed by development of degeneration on days 2-4 in neuron populations including the septohippocampal nucleus, septohypothalamic nucleus, anterior olfactory nucleus, bed nucleus of the stria terminalis, endopiriform nucleus, parafascicular nucleus, superior colliculus, interstitial nucleus of the posterior Commissure, Inferior Colliculus, pontine nuclei, raphe nuclei, pars caudalis of the spinal trigeminal nucleus, the caudal aspect of nucleus tractus solitarius, dorsal vagal motor nucleus, granule cells in the dentate gyrus, pyramidal cells in CA fields of the hippocampus, and of neurons in the subiculum, pyriform cortex, entorhinal cortex and neocortex (mainly layer Vb and VI).
Each type of afferent source was also seen in the nucleus of the posterior Commissure and the posterior ventral lateral hypothalamic area.
As well as the strong ipsilateral projection, there was a much weaker contralateral one which crossed the midline in the tectal Commissure.
The deep laminae were mainly connected with auditory, somatosensory and reticular regions of the brain, including the Inferior Colliculus, zona incerta, substantia nigra, mesencephalic central grey, pontine nuclei, spinal trigeminal nucleus, nucleus of the posterior Commissure, thalamic reticular nucleus, raphe nuclei, lateral vestibular nucleus, the lateral superficial reticular formation of the medulla, the mesencephalic reticular formation, nucleus gracilis and the cervical spinal cord.
In addition, three axonal systems each oriented in a different plane of the Commissure of the Inferior Colliculus were described.
There was also a much sparser contralateral descending projection that crossed midline in the tectal Commissure, and sent terminals to the contralateral cuneiform area and adjoining regions.
In the spinal cord cells were found in the substantia gelatinosa at all levels, the dorsolateral funiculus and dorsal gray Commissure in lumbosacral cord. The presence of neuropeptide Y immunoreactive fibres in tracts such as the corpus callosum, anterior Commissure, lateral olfactory tract, fimbria, medial corticohypothalamic tract, medial forebrain bundle, stria terminalis, dorsal periventricular bundle and other periventricular areas, indicated that in addition to the localisation of neuropeptide Y-like peptide(s) in interneurons in the forebrain, neuropeptide Y may be found in long neuronal pathways throughout the brain..
The commissural nucleus is composed of cells with a simple dendritic branching pattern perpendicular or parallel to the fibers of the intercollicular Commissure.
In the Inferior Colliculus of the mouse, 4 cell types project across the collicular Commissure: small to medium sized spiny cells, small to medium sized spineless cells, medium sized sparsely spinous neurons and large cells.
Using high resolution autoradiography, the accumulation of radioactivity after intravenous injection of [ 1-14C]glucose was measured in the corpus callosum, hippocampus, dorsal hippocampal Commissure, somatosensory cortex, Inferior Colliculus and pontine periaqueductal grey.
Fibers arising from the cerebellar nuclei were traced via the cerebellar Commissure to the contralateral vestibular nuclear complex (particularly the n. Vestibular projections ascending mainly via the f lm terminated in the nuclei of the f lm, the nuclei of the posterior Commissure, and particularly the extraocular motor nuclei.
of the posterior Commissure, the superior colliculus, the n.
Experiments conducted after large HRP deposits invading almost all the collicular layers resulted in the labeling of visual centers (cortical areas 17, 18 and 18a, ventral lateral geniculate nucleus, nucleus of the posterior Commissure, nucleus of the optic tract, anterior and olivary pretectal nuclei, parabigeminal nucleus); somatosensory centers (cortical area SmI, principal and spinal tract trigeminal nuclei) auditory centers (auditory cortex, Inferior Colliculus and nuclei of the lateral lemniscus) and various other centers (zona incerta, substantia nigra, cingulate and motor cortices, and some hypothalamic, thalamic, pontine reticular and deep cerebellar nuclei). Deposits limited to the deep SC layers resulted in the labeling of a smaller number of structures: visual centers (cortical area 18a, nucleus of the posterior Commissure, parabigeminal nucleus); somatosensory centers (cortical area SmI, principal and spinal tract trigeminal nuclei); auditory centers (Inferior Colliculus, nuclei of the lateral lemniscus); and various other centers (zona incerta, substantia nigra, cingulate cortex, some hypothalamic nuclei, posterior thalamic nucleus, central gray, cuneiformis and subcuneiformis nuclei, pontine reticular nucleus pars oralis).
Neurons were classified according to soma shape, dendritic arborization and location within the Commissure.
Systematic tracking with the stimulating electrode in and around the FFH revealed that effective sites of stimulation inducing negative field potentials in the IO subdivision of the oculomotor nucleus, identified as extracellular counterparts of the EPSPs in IO motoneurons, were also located in the interstitial nucleus of Cajal, nearby reticular formation and posterior Commissure, besides within and near the medial part of the FFH.
Some labeled fibers entered the Commissure of the Inferior Colliculus where they were traced into the dorsal cortex and rostral pole of the Inferior Colliculus on the side contralateral to the injection site.
Most studies of the Commissure have utilized small lesions or tracer deposits; while all agree that commissural axons terminating in the IC do so in its superficial and dorsomedial sectors, it is not clear where projecting cell bodies are located in the IC. The present study attempted total infiltration of the Commissure of the cat IC with horseradish peroxidase (HRP) in an effort to label all neuronal somas whose axons cross in the Commissure. These results, in conjunction with those from studies of the terminations of commissural axons made by others, suggest that the interconnections of the inferior colliculi through their Commissure are complementary, rather than reciprocal..
Most previous neuropathologic cases reported in human beings have consisted of much larger lesions with common involvement of the posterior Commissure and pretectum.
In the pretectum, NBIC fibers terminate in the anterior and medial nuclei and the nucleus of the posterior Commissure.
During systematic observation of the cellular subnuclei of the Inferior Colliculus of adult rats, it was noted that in the zone of the intercollicular Commissure, numerous neuronal perikaria appear intermingled between the commissural fibers. A fourth neuronal group, situated between the Commissure and the upper periventricular zone, is also in relation with the commissural fibers. The constancy of these neurons and their frequently axodendritic and axosomatic synapses suggest that they play an important role in the whole function of the Commissure which, at present, is not well understood in spite of the number and distinct origin of their afferents..
The neurological deficits following section of the midbrain Commissures were studied in the cat. After a lesion of the Commissures between the superior and inferior colliculi, with or without involvement of the posterior Commissure, the animals showed a long lasting inattention for stimuli in the upper visual space, lack of exploratory head movements towards the neglected space, head ventroflexion and vertical paralysis of gaze. After a lesion of the Commissure between the superior colliculi or of its rostral part only, the same symptomatology appeared, but it was short lasting. After a lesion of the posterior Commissure, the head was kept dorsiflexed, the exploratory head movements towards the lower visual space were reduced and the stimuli presented in this space were often neglected.
White matter of the corpus callosum, anterior Commissure, alveus, fornix, fimbria, and medullary pyramids showed the most severe myelin paucity.
Aggregates of CRF-immunoreactive perikarya are found in the paraventricular, supraoptic, medial and periventricular preoptic, and premammillary nuclei of the hypothalamus, the bed nuclei of the stria terminalis and of the anterior Commissure, the medial septal nucleus, the nucleus accumbens, the central amygdaloid nucleus, the olfactory bulb, the locus ceruleus, the parabrachial nucleus, the superior and Inferior Colliculus, and the medial vestibular nucleus.
Autoradiographic experiments showed that the incertofugal fiber systems reach ipsilaterally to the thalamus (lateral dorsal, central lateral, ventral lateral geniculate, parafascicular, subparafascicular and reuniens nuclei, and posterior nuclear complex), to the hypothalamus (dorsal, lateral and posterior hypothalamic areas), to the tectum (medial pretectal area, deep pretectal and pretectal nuclei, superior colliculus and periaqueductal gray) and to the midbrain tegmentum, pons and medulla oblongata (subcuneiform, cuneiform and red nuclei, nuclei of the posterior Commissure and Darkschewitsch, interstitial nucleus of Cajal, pedunculopontine tegmental nucleus, oral and caudal pontine reticular nuclei, nucleus raphe magnus, gigantocellular reticular nucleus, pontine gray and inferior olivary complex).
Only a few cells were labeled in the contralateral optic tectum, suggesting that few of the fibers of the intertectal Commissure are actually commissural to the tectum.
After injections of horseradish peroxidase into the central tegmental field of the midbrain reticular formation and centrum medianum of the thalamus in the cat, labelled neurons were found in the nucleus of solitary tract, cuneate and gracile nuclei, spinal nuclei of trigeminal nerve, external nucleus and brachium nucleus of Inferior Colliculus, nuclei of the lemniscus lateralis in the area pretectalis, nucleus of the posterior Commissure and stratum intermediale of the superior colliculus and in reticular structures of medulla and pons.
All labeled fibers bound for the contralateral side cross in the dorsal part of the midbrain tegmentum at the intercollicular levels via the so-called Commissure of Probst.
Small microelectrophoretic injections of tritiated proline and leucine practically confined to the ZI were found to label a widespread, predominantly ipsilateral system of descending and ascending fibers distributed to reticular structures of the brain stem (mesencephalic reticular formation, nucleus tegmenti pedunculopontinus pars compacta, parabrachial area, nuclei reticularis pontis oralis, pontis caudalis, gigantocellularis and medullae oblongatae, pars ventralis), precerebellar nuclei (nucleus reticularis tegmenti pontis, pontine nuclei and inferior olivary complex), the middle and deep layers of the superior colliculus, the pretectum (anterior, posterior and medial pretectal nuclei), perioculomotor nuclei (interstitial nucleus of Cajal, nucleus of Darkschewitsch and nuclei of th posterior Commissure), the parvocellular portion of the red nucleus, the central gray substance, the nucleus tegmenti dorsalis lateralis, the ventral horn of the cervical spinal cord, non-specific thalamic nuclei (parafascicular, centralis medius, paracentralis, centralis lateralis and ventromedial thalamic nuclei, nucleus reuniens), basal ganglia (entopeduncular nucleus and globus pallidus), hypothalamic structures (posterior hypothalamic nucleus, dorsal and lateral hypothalamic areas), and a subpallidal district of the substantia innominata.
Pretectofugal fibers projecting to nuclei in this third category terminate ipsilaterally within the nucleus of Darkschewitsch, bilaterally within the nucleus of the posterior Commissure and the interstitial nucleus of Cajal, and contralaterally within the somatic cell column of the oculomotor and trochlear nuclei.
Contralaterally, every subnucleus of IC except for PC projects via the Commissure of IC to areas corresponding to the targets of the ipsilateral projections, such as the ventral and medial divisions of MGB and the parabrachial region and the interstitial nucleus of BIC, although these contraleral projections are in general much sparser than those ipsilateral.
Terminal axonal branchings which get into the nucleus studied via the interquadrigeminal Commissure were detected near these neurons.
(1) The NOTL-contralateral NOTL fibers, which connect bilateral NOTLs through a part of the posterior Commissure.
Visual structures: ventral lateral geniculate nucleus, parabigeminal nucleus, pretectal area (nucleus of the optic tract, posterior pretectal nucleus, nuclei of the posterior Commissure).
After deep collicular injections numerous labeled cells were consistently found in the parabigeminal nucleus, the mesencephalic reticular formation, substantia nigra pars reticulata, the nucleus of posterior Commissure, the pretectal area, zona incerta, and the ventral nucleus of the lateral geniculate body. In some cases, HRP-positive cells were seen in the nucleus of posterior Commissure, the pretectal area, Forel's field, and nucleus reticularis thalami.
Labeled axons also pass to the opposite, or contralateral colliculus via the tectal Commissure.
The nucleus of the posterior Commissure (NPC) and its subdivisions do not receive any of these inputs. The projections of the pretectum involve a number of structures within the thalamus and brain stem and there are differences in the projection targets of the pretectal region which receives direct visual input (i.e., SL and ON) and the region which does not (i.e., nucleus of the posterior Commissure, NPC).
including the internuclear cortex and Commissure had no effect on obstacle-avoidance performance.
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