Deep Layer Of Superior Colliculus

GLY given in the deep layer of superior colliculus did not produce changes in tail-flick latencies.  

deep layer SC neurons exhibited robust presaccadic activity the magnitude of which was unaffected by task difficulty when the stimulus specified a saccade toward a target within the neuron's response field.  

It is classically divided into superficial layers predominantly containing visual neurons and deep layers containing multisensory and premotor neurons. Investigations of intrinsic connectivity within the SC in non-human species initially led to controversy regarding the existence of interlaminar connections between superficial and deep layers. In these sections, an axon bundle having roughly the same diameter as the injection site crossed all deep layers, and individual axons displayed en passant or terminal boutons.  

However, regardless of the rostro-caudal or medio-lateral position of the superficial layer stimulation site, the proportion of the deeper layers activated remained remarkably constant, although the volume of activated deep layer tissue was shifted in each case toward the central regions of the SC. This last observation argues against the precise alignment of the superficial and deep layer visual maps, suggesting instead that the arrangement of the superficial layer projection may more closely relate to the organization of deep layer auditory and/or somatosensory representations..  

No significant elevation of Fos expression was observed in the cochlear nucleus and the deep layer of the superior colliculus of either type of mice.  

PHA-L-immunoreactive (IR) fibers showing preterminal and terminal-like arborization that contained proTRH were identified in the dorsolateral and lateral PAG, deep layer of superior colliculus (CS), parafascicular nucleus (PF), ventromedial zona incerta (ZI) and at the border of the locus coeruleus (LC) and Barrington's nucleus.  

The present study shows that, in contrast to more altricial species, many deep layer SC neurons in the rhesus monkey are multisensory at birth.  

Comparisons of images, obtained by double staining for microtubule-associated protein-2 or glial fibrillary acidic protein, indicated that the increased immunoreactivity was localized on both apical dendrites of deep layer neurons and glial cells.  

Although these cell types were found in all three layers of the SC, the majority of tonic theta-ON cells were recorded in the intermediate layer, and the tonic theta-OFF cells were dispersed evenly between the intermediate layer and the deep layer of the SC.  

When superficial layers form, Ol-Prx3 expression becomes restricted to the underlying deep layer, where it persists in the adult.  

The deep layer 3 terminals spread out over a diameter of 400 microm on average and their degree of branching is moderate.  

This dorsal cochlear nucleus non-monotonicity may indicate that, at higher levels of stimulation, a secondary indirect inhibitory input, probably associated with activation of deep layer dorsal cochlear nucleus cells, reduces excitatory responses at the superficial layer of the dorsal cochlear nucleus.  

Dendrites of TO2 cells have the largest dendritic trees that arborize in the intermediate and deep layers of retinal afferents; axons constitute a lateral uncrossed tectospinal tract. TO3 cells have widefield dendritic trees that arborize in the deep layer of retinal afferents and in the layer of tectal efferents; axons constitute a superficial uncrossed tectospinal tract.  

Azimuthal spatial tuning properties of deep layer multiunits of anesthetized guinea pigs were examined approximately 20 days after implantation of the Elvax polymer.  

Parasagittal slices of the ferret superior colliculus were prepared for in vitro recording, and 125 intermediate/deep layer neurons were examined in response to electrical stimulation rostral or caudal to the recording site.  

These anticonvulsant effects use a circuitry that may involve the ventromedial thalamic nucleus, the deep layer of the superior colliculus, or both. The second region is in the posterior SNR, and muscimol infusions produce proconvulsant effects, perhaps mediated by the striatum, the globus pallidus, the deep layer of the superior colliculus, or all three.  

The electrode performance was evaluated in 42 implanted rats where the system was used successfully for long term recording of superior colliculus (SC) deep layer neurons and behavioural responses evoked by electrical stimulation of the same wires.  

More than a quarter (27.8%) of the deep layer population responded to stimuli from more than a single sensory modality. Most deep layer visually responsive neurons were binocular and exhibited poor selectivity for such stimulus characteristics as orientation, velocity, and direction of movement.  

Current models assign a crucial role to the deep layers of the superior colliculus (SC) in the dynamic feedback control of saccadic eye movements. However, if the SC is to be part of the local feedback loop for saccades, it is expected that the movement-related firing patterns of deep layer SC cell maintain a fixed relation with the instantaneous saccade trajectory, regardless of the conditions that evoked the saccade.  

Only increases in glucose utilization were produced by D-Ala2; MePhe4, Gly-ol5-enkephalin in brain regions involved in motor control, including the globus pallidus, the substantia nigra, pars reticulata, the nucleus ruber and the cerebellum, and brain regions involved in visual processing--the visual cortex and superior colliculus deep layer.  

deep layer cells were divided into eight morphological classes.  

A much more faintly labeled population of oval cells was observed in the deep layer of retrosplenial and posterior cingulate cortex, and in the granular layer of somatosensory frontoparietal cortex.  

Cell bodies of the labeled giant cells lay in the deep layer of the DCN. Dendrites, widespread both along the isofrequency axis and along the tonotopic axis, occupied mainly the deep layer, but some distal ends strayed into the molecular layer.  

The results show that TST somata are found only in the intermediate and deep layers. The ratio of numbers of TST somata in the intermediate relative to the deep layer varies widely, from 0:1 (in rabbits) to over 8:1 (in marmosets).  

The aim of this study was to determine the functional importance of intrinsic connections within the hamster's superior colliculus (SC) in the development of the visual responses of neurons in the deep layers of this nucleus. We also determined the morphology of a number of the deep layer cells recorded in these experiments by intracellular injection of HRP. Injection of lidocaine into the superficial layers completely abolished the visual- and/or optic chiasm-evoked responses of all 40 deep layer cells tested. Thus, fibers that either pass through or synapse in the superficial layers are necessary for the visual responses of deep layer neurons. Injections of CoCl2 restricted to the superficial layers significantly reduced the visual responsivity of 86% of 92 deep layer neurons tested and abolished the visual responses of 68% of these cells. Superficial layer injections of CoCl2 were equally effective in reducing the responses of neurons with dendrites that ascended into the superficial layers (all seven cells tested and recovered) and those of cells with dendrites restricted to the deep layers (six of seven cells tested and recovered). Injections of CoCl2 into the deep layers, in the region of the cell being recorded, significantly reduced the visual responses of 59% of 37 cells and abolished the visual responses of 40% of the neurons tested. Deep CoCl2 injections abolished the visual responses of three of four cells with dendrites restricted to the deep layers and only one of four cells with dendrites that ascended into the superficial layers. Also, some deep layer neurons in this species may receive effective visual input through their dendrites that ascend into the superficial layers, where they are likely to be contacted by retinal axons or axon collaterals of superficial layer cells..  

Neurons in the deep layers of the superior colliculus in behaving hooded rats were tested for responsivity to visual, auditory, or somesthetic stimuli.  

The topographic organization of the somatosensory representation in the deep layers of the cat superior colliculus was reexamined using methods previously used to examine the visuotopy in these layers. This technique identified the distribution of neurons in the superior colliculus that represent a designated region of the body surface (i.e., a dermal image), as well as assessed the differential distribution of deep layer neurons representing different body regions (e.g., face, forelimb, hindlimb, etc.). Each region of the body surface, however, was represented within a surprisingly broad area of the deep layers, which often had considerable overlap with the representations of adjacent body regions. This organization was similar to that of the deep layer visuotopy and emphasizes that the representation of a peripheral stimulus is accomplished by the simultaneous activation of a large population of deep layer neurons.  

While the heaviest anterogradely labeled ascending projections were observed to the contralateral ventral posterolateral nucleus of the thalamus, pars oralis (VPLo), efferent projections were also observed to the contralateral ventrolateral thalamic nucleus (VLc) and central lateral (CL) nucleus of the thalamic intralaminar complex, magnocellular (and to a lesser extent parvicellular) red nucleus, nucleus of Darkschewitsch, zona incerta, nucleus of the posterior commissure, lateral intermediate layer and deep layer of the superior colliculus, dorsolateral periaqueductal gray, contralateral nucleus reticularis tegmenti pontis and basilar pontine nuclei (especially dorsal and peduncular), and dorsal (DAO) and medial (MAO) accessory olivary nuclei, ipsilateral lateral (external) cuneate nucleus (LCN) and lateral reticular nucleus (LRN), and to a lesser extent the caudal medial vestibular nucleus (MVN) and caudal nucleus prepositus hypoglossi (NPH), and dorsal medullary raphe.  

The glutamate contained in the superficial grey layer (SGL) and deep layer was measured in the sectioned freeze-dried sample using an enzymatic cycling method of NAD-NADH.  

Injections of wheat germ agglutinin-horseradish peroxidase were made into the PAG of 12 adult rats and into the deep layer of the superior colliculus in 2 rats.  

deep layer units of SC in addition respond to auditory and somatosensory stimuli, but the proportion of such non-visual cells is usually found to be much lower than that of visual cells.  

Not all cell types in the superficial layers contributed equally to this interlaminar projection: 78.6% (n = 11) of the recovered wide-field vertical cells, 55.0% (n = 11) of the narrow-field vertical cells, 16.7% (n = 2) of the stellate cells, 40.0% (n = 2) of the marginal cells, 18.2% (n = 2) of the horizontal cells, and 28.6% (n = 2) of neurons we could not classify on the basis of their somadendritic morphology projected to the deep layers. These results, along with those of a previous study (Mooney et al., 1984), which demonstrated that the dendrites of deep layer cells may extend through the SO and into the SGS, indicate that there is an extensive anatomical substrate by which sensory information may be communicated from superficial to deep layer SC neurons..  

Superficial SC neurons (APNs, ILNs) could be attached to the allo- and idiodendritic type while deep layer neurons (TRSNs) belong to the isodendritic type. Both the morphometrical data and the electronic properties underline the contrasting features of superficial vs deep layer neurons in the SC.  

Neurons in the CORo were activated antidromically by electrical stimulation of the deep layer of the superior colliculus (SC).  

The projections from these auditory structures terminate mainly in the central tier of the deep layer.  

These results suggest that the dorsal and lateral regions of PAG play an important role in the saccadic system, probably through long lead burst units in the deep layer of the superior colliculus and/or pontine reticular formation..  

The remaining labelled cells were found mainly in the deep layers.  

These findings show that an anatomical substrate for communication from superficial to deep layer cells exists in the hamster SC, but that such communication may not necessarily be reflected in the response of deep layer neurons..  

SN-stimulation in VM-intact rats resulted in metabolic activation within the deep layer of superior colliculus, subthalamic nucleus, ventrolateral thalamus and sensory-motor cortex ipsilaterally, and bilaterally in the reticulata, compacta, centrolateral and ventromedial thalamus, striatum, globus pallidus and entopeduncular nucleus.  

The effects of acute infraorbital (i.o.) nerve section upon the responses of somatosensory cells in the rostral part of the deep layers of the hamster's superior colliculus were studied using standard extracellular single-unit recording and receptive field mapping techniques.  

Significant focal alterations in glucose utilization occurred in a number of other regions ipsilateral to the injection, including lateral habenular nucleus (increased by 16%), pars compacta of the substantia nigra (increased by 28%), ventrolateral nucleus of the thalamus (decreased by 40%), sensory-motor cortex (decreased by 47%), deep layer of the superior colliculus (decreased by 18%), and subthalamic nucleus (decreased by 18%).  

More moderate projections go to the medial division of the periaqueductal gray (PAGm), the cuneiform nucleus (CF), the mesencephalic reticular formation (MRF), lateral part of the deep layer of the superior colliculus (SP) and magnocellular medial geniculate nucleus (GMmc), while scattered spinal fibers are present in the dorsal part of the periaqueductal gray (PAGd), the external inferior collicular nucleus (IX), the intermediate layer of the superior colliculus (SI), the lateral part of the red nucleus (NR) and in the Edinger-Westphal portion of the oculomotor nucleus (3).  

Projections to primarily the contralateral inferior colliculus arise in the dorsal and ventral cochlear nuclei, the auditory nerve nucleus and the spinal trigeminal nucleus pars caudalis, while ipsilateral projections arise in the superior paraolivary nucleus, the ventral nucleus of the trapezoid body, the ventral nucleus of the lateral lemniscus, the paralemniscal nucleus, the deep layer of the superior colliculus and the parabrachial nucleus.  

In the superior colliculi of cats anesthetized with ketamine, 84% of identified output cells of the deep layers could be driven by shocks to the contralateral optic disk, optic chiasm, or ipsilateral optic tract; 75% of these deep-layer cells had response latencies reflecting a polysynaptic influence of retinal Y-cells. Thus, one or more of these visual areas may be important for the relay of retinal information, and particularly of Y-cell information, to the deep layers of the superior colliculus. The distributions of activation latencies were similar to those observed in the superficial layers, raising the possibility that at least some of the cortical influence on the deep layers may be mediated by direct connections. Cells of the deep layers were more likely to be excited by a cortical stimulus that activated cells immediately above them in the superficial layers than by a stimulus that did not.  

The neurons were widely distributed in the deep layer of the anterior two-thirds of the superior colliculus.  

Cells in the ipsilateral somatosensory cortex and contralateral dorsal horn of the spinal cord, dorsal column nuclei, lateral cervical nucleus, internal basilar nucleus, nucleus of the spinal trigeminal tract and deep layers of the superior colliculus were labeled following HRP injections centered in the deep tectal laminae. The response characteristics of somatosensory corticotectal, spinotectal and intertectal neurons were investigated with extracellular single unit recording methods and, with the exception of the fact that the receptive fields of corticotectal and spinotectal neurons were consistently smaller than those of cells recorded in the colliculus, the response characteristics of these neurons were quite similar to those of somatosensory neurons in the deep layers of the tectum. Lesions of the somatosensory cortex or dorsal half of the spinal cord were also combined with single unit recording in the colliculus to determine whether or not such damage altered the incidence and/or response characteristics of deep layer somatosensory cells.  

Units of the deep layer of the colliculus, not sensitive to visual activation, are inhibited by proprioceptive stimulation.  

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