Pretectal Area

This area corresponds with the pretectal area, including the rostral interstitial nucleus of the medial longitudinal fasciculus, with sparing of the oculomotor and rubral nuclei.  

Single-unit recordings were performed from a retinorecipient pretectal area (corpus geniculatum laterale) in Scyliorhinus canicula.  

We have examined the organization of the pretectal area in two monotremes (the short beaked echidna-Tachyglossus aculeatus, and the platypus-Ornithorhynchus anatinus) and compared it to that in the Wistar strain rat, using Nissl staining in conjunction with enzyme histochemistry (acetylcholinesterase and NADPH diaphorase) and immunohistochemistry for parvalbumin, calbindin, calretinin and non-phosphorylated neurofilament protein (SMI-32 antibody).  

Staining was identified in the olfactory glomeruli, pallium and subpallium of the telencephalon; epithalamus, thalamus, preoptic area, and hypothalamus of the diencephalon; pretectal area, optic tectum, torus semicircularis, and tegmentum of the mesencephalon; all layers of the cerebellum; reticular formation; nucleus of the solitary tract, octaval nuclei, and dorsal column nuclei of the medulla; and dorsal and motor fields of the spinal cord.  

Cytoarchitectonics of outer nuclei of the pretectal area was studied in four species of the sturgeons: the great sturgeon Huso huso, L., the Russian sturgeon Acipenser güldenstädti persicus n. In this part of the pretectal area, five nuclear structures were described: parvicellular and magnocellular outer pretectal nuclei, lamellar pretectal nucleus, and dorsal pretectal nucleus, as well as accessory optic nucleus. Besides, a general conclusion is presented on organization of their entire pretectal area..  

Cytoarchitectonics of periventricular and central nuclei of the pretectal area was studied in four species of the sturgeons: the great sturgeon Huso huso, L., the Russian sturgeon Acipenser güldenstädti persicus n. Study of these parts of the pretectal area was carried out by methods of Nissl and Bielshowskii modified by Viktorov. In this part of the pretectal area, nine nuclear structures were described, eight of them--nuclear; these are ventral periventricular pretectal nucleus and its dorsal component, dorsal periventricular pretectal nucleus, nucleus of medial longitudinal bundle, subcomissural organ, medial and lateral intercalate nuclei, and central and posterior pretectal nuclei. The main attention has been paid to the issue of the evolutional progression of this part of the pretectal area in the sturgeons as compared with other Actinopterygii..  

Considerable immunoreactivity was seen in the optic tectum, rostral torus semicircularis, central pretectal area, and granule cells of the cerebellum.  

Exp Eye Res 43:867-869) to quantitatively assess the effects of albinism on retinal projections to a number of subcortical visual nuclei including the ventral lateral hypothalamus (VLH), ventral lateral preoptic area (VLPO), olivary pretectal nucleus (OPN), posterior limitans (PLi), commissural pretectal area (CPA), intergeniculate leaflet (IGL), ventral lateral geniculate nucleus (vLGN) and superior colliculus (SC).  

Cingulate, retrosplenial, sensory-motor and insular cortex, medial and lateral posterior thalamic nuclei, pretectal area, hypothalamus and periaqueductal gray were the most consistently, often bilaterally activated regions.  

After 4 weeks, serial fragmatome sections were obtained in the pretectal area and further stained with propidium iodide (PI stains DNA) to delineate the pretectal nuclei in the dorsal midbrain.  

Subcortical moderate to weak projections reach the PAG from the central and medial amygdala, nucleus of the stria terminalis, septum, nucleus accumbens, lateral preoptic region, lateral and posterior hypothalamus, globus pallidus, pretectal area, deep layers of the superior colliculus, the pericentral inferior colliculus, mesencephalic trigeminal nucleus, locus coeruleus, substantia nigra pars compacta, dorsal and ventral raphe, vestibular nuclei, spinal trigeminal nucleus, solitary tract nucleus, and nucleus gracilis.  

Neurons exhibiting 5HT-immunoreactivity (5HT-IR) are detected from 45 h postfertilization (hpf) in the ventral hindbrain raphe, the hypothalamus, pineal organ, and pretectal area.  

MRI revealed that the lesion was predominantly located within the pulvinar, extending to the lateroposterior thalamic nuclei and to the pretectal area with possible involvement of the medial geniculate body.  

Other retinorecipient and/or tectorecipient nuclei (ventral geniculate nucleus, lateral dorsolateral nucleus, superficial synencephalic nucleus, pretectal area, and griseum tectale) also show a differential immunoreactivity for OL-protocadherin and other cadherins.  

Anterogradely labeled fibers projected from BON following three paths, a lateral bundle to the ipsilateral dorsal midbrain, an intermediate bundle to the ipsilateral pretectal area or the posterior commissure and a ventral fiber bundle to the tegmentum bilaterally. Fibers that coursed via the intermediate bundle to the posterior commissure were also seen reaching the contralateral pretectal area and the contralateral BON.  

We have found novel projections from RGCs that express melanopsin mRNA to the ventral subparaventricular zone (vSPZ), a region involved in circadian regulation and negative masking, and the sleep-active ventrolateral preoptic nucleus (VLPO) and determined the subsets of melanopsin-expressing RGCs that project to the SCN, the pretectal area (PTA), and the IGL division of the lateral geniculate nucleus (LGN).  

In the midbrain, labeled fibers were observed in the interpeduncular nuclei, ventral tegmental area, periaqueductal gray, superior colliculus, pericentral inferior colliculus, pretectal area, the raphe nuclei, and the nucleus reticularis pontis oralis.  

In addition, three other groups can be distinguished: one group in the ventral thalamus; one in the pretectal area, and one found in the postoptic commissure and above the pituitary stalk in a few brains.  

In the midbrain and pons, labeled fibers were located in the anterior pretectal area, superior colliculus and in the dorsolateral portion of the central gray.  

At 4 d, higher order neurons were revealed in trigeminal, auditory, vestibular, and deep cerebellar nuclei (medial, interpositus, and lateral), oculomotor and visual-related structures (Darkschewitsch, nucleus of the posterior commissure, deep layers of superior colliculus, and pretectal area), lateral hypothalamus, and cerebral cortex (particularly in parietal areas).  

THir cells were also seen in other forebrain areas (retrobulbar area, dorsal and ventral telencephalic areas, hypothalamus, ventral thalamus, pretectal area) and in the brainstem (locus coeruleus, viscerosensory area, caudal reticular formation, and area postrema).  

No VIP neurones were observed in the human pretectal area, but numerous NPY cells were found in the 'nucleus lentiformis', and in the anterior bulge of the pretectum, while the 'nucleus sublentiformis' contained an abundant NPY fibre network. Accordingly, the 'nucleus lentiformis' (which contains numerous NPY cells) corresponds to the nucleus of the optic tract, the 'nucleus sublentiformis' (containing a dense network of NPY fibres) to the posterior pretectal nucleus, and the 'nucleus of the pretectal area' corresponds to the medial pretectal nucleus.  

The colocalization of GABA, enkephalin and neuropeptide Y immunoreactivity in neurons in the pretectal area and in the mesencephalic tectum of the green frog (Rana esculenta) was studied. In the pretectal area no colocalization of the investigated peptides and GABA was found..  

In both species, the pinealofugal fibers coursed to the dorsomedial thalamus, the medial pretectal area, the posterior tubercle, and the medial mesencephalic tegmentum and branched profusely in these areas.  

In the midbrain and pons, labelled fibres were located in the anterior pretectal area, Darkschewitsch nucleus, superior colliculus and dorsolateral portion of the central gray.  

Subcortical visual nuclei, including the ventral lateral geniculate nucleus and intergeniculate leaflet, pretectal area, and superior colliculus, and the subthalamus (zona incerta, fields of Forel) also project to the PHA.  

A caudal pathway projects medially to the posterior hypothalamic area and periaqueductal gray and caudally along the brachium of the superior colliculus to the medial pretectal area and the nucleus of the optic tract (IGL and VLG).  

The NCAT receives bilateral auditory input from the cochlear nuclei and sends projections to regions outside the classical acoustic pathway like the pretectal area or the superior colliculus.  

Distinct PY or PYY mRNA cell groups were localized in the pretectal area and synencephalon or posterior tubercle, respectively.  

These results indicate that the optic tectum and the pretectal area of the rainbow trout are major sites of integration of the melatonin signal, express the clock gene, and may act as biological clocks to influence behavioral and endocrine responses in trout..  

Recent research has demonstrated that aspiration lesions of the superior colliculus (SC) and pretectal area attenuated REM sleep triggering.  

Melatonin receptors were associated predominantly with visually related areas of the trout brain, such as the thalamic region, the pretectal area, and the optic tectum.  

The stem axon has an additional very dense terminal arborization in the neuropil of the nucleus Bellonci pars medialis and additional sparse collaterals in the pretectal area..  

Within the forebrain, the formation of the anterior and postoptic commissures is delayed and the expression of markers within the pretectal area is reduced.  

After large injections of PHA-L into both the superficial and deep laminae of the MDH, labeled fibers were observed in the anterior pretectal area (ATP), internal gray matter of the superior colliculus (InG), and rostral linear raphe nucleus (RLi) in the contralateral mesencephalon, and also in the ipsilateral parabrachial nucleus (PBA).  

Expression of the immediate early genes c-fos and fosB was examined by immunocytochemistry in the suprachiasmatic nucleus (SCN), the intergeniculate leaflet (IGL) of the thalamus, and the medial pretectal area of hamsters that ran vigorously in the novel wheel and would have phase-shifted.  

The fibers of these tracts could be followed to their different targets in the brain, namely the preoptic region, the rostral habenulae, the medial subhabenular and retrohabenular (post- and subcommissural) region, the medial thalamus, the dorsal hypothalamus, the pretectal area, and medial and dorsolateral tegmental mesencephalic regions (interstitial nucleus of Cajal, oculomotor nucleus, mesencephalic reticular area, nucleus profundus mesencephali, and central gray).  

Lesions of the visual cortex or the superior colliculus-pretectal area were performed in albino rats to determine retinorecipient areas that mediate the effects of light on behavior, including rapid eye movement sleep triggering by lights-off and redistribution of non-rapid eye movement sleep in short light-dark cycles. Acute responses to changes in light conditions were virtually eliminated by superior colliculus-pretectal area lesions but not by visual cortex lesions.  

Additional neuronal labeling was observed postnatally in the olfactory bulb, cerebral cortex, amygdala, various nuclei of the thalamus, interpeduncular nucleus, linear nucleus of the raphe, pretectal area and superior colliculus.  

In the pretectal area, we found the tractus opticus accessorius and the nucleus opticus dorsolateralis.  

3) R-type axons originating from both areas V1 and MT can branch to other structures; namely, the superior colliculus, the pretectal area, and/or the reticular nucleus of the thalamus.  

Similarly, areas that receive photic input, such as the retina, the intergeniculate leaflet, and the pretectal area, densely innervate the ventral SCN but provide only minor innervation of the dorsal SCN.  

Thus, as revealed by anatomical and molecular analyses, only Otx1-/-; Otx2+/- embryos lacked mesencephalon, pretectal area, dorsal thalamus and showed an heavy reduction of the Ammon's horn, while the metencephalon was dramatically enlarged occupying the mesencencephalic area.  

The pretectal area contained degenerated fibers which were widespread in (i) the nucleus of the optic tract, (ii) olivary pretectal nucleus, (iii) anterior pretectal nucleus, and (iv) the posterior pretectal nucleus.  

A commissural pretectal area (CPT) sparsely innervated by retina is also described.  

Efferent projections of the paralemniscal tegmental area reach the putamen bilaterally, the nucleus accumbens and other parts of the basal ganglia, the pretectal area, the substantia nigra, the intermediate and deep layers of the superior colliculus bilaterally and the tegmental area ventral to it.  

parafascicularis, Pf, n = 163) and in the pretectal area (Pt, n = 75) was examined following chronic electrolytic lesions of the nucleus reticularis thalami (nRT) in ketamine-anaesthetized rats after single electrical stimuli to the ventrobasal complex (VB).  

parafascicularis, Pf), the pretectal area (Pt) and lateral thalamic nuclei (ventrobasal complex, VB, ncl. Lateral thalamic neurones responded to electrical stimulation of the intralaminar nuclei or the pretectal area with the same pattern of response.  

To analyze the effect of stimulation of the pretectum on the tectal EP, we stimulated the pretectal area pharmacologically.  

Moderately correlated with attack were 4 visual areas: the dorsal and ventral lateral geniculate nuclei, pretectal area, and superior colliculus.  

After injection of biocytin into the ipsilateral optic tectum, labeled terminals were seen in the rotund nucleus (Rt), neuropil part of the ventral lateral geniculate nucleus (GLnv), principal part of the dorsal lateral geniculate nucleus, lateral part of the dorsolateral thalamic nucleus, triangular nucleus (T), superficial parvocellular nucleus (SPC), pretectal nucleus, pretectal area (PA), subpretectal nucleus, central gray matter (GC), isthimo optic nucleus (ION), magnocellular and parvocellular parts of the isthimo nuclei (Imc and Ipc), semilunar nucleus (SLu), lateral and medial pontine nuclei and reticular formation (FRM) of the medulla, ipsilaterally.  

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)..  

Labeled fibers and cell groups are observed in the pretectal area, the mesencephalic optic tectum, and the torus semicircularis.  

These cell groups are located in the dorsal telencephalic area, the inferior lobes of the hypothalamus, the pretectal area, the magnocellular superficial pretectal nucleus, the optic tectum, the oculomotor nucleus, the trochlear nucleus, the magnocellular vestibular nucleus, the secondary gustatory nucleus, the superior and medial reticular nuclei, the motor nucleus of the vagus and the ventral horn of the spinal cord.  

COX 2-ir neurons were also observed in the subparafascicular nucleus, the medial zona incerta, and pretectal area.  

The regions of the P28 brain in which the thrombin receptor mRNA was present include the substantia nigra and the ventral tegmental area, the pretectal area, some hypothalamic nuclei and some cells of the cerebral cortex.  

Axons of immunostained cells in the pretectal area, and torus semicircularis could be followed to the tectum.  

Norepinephrine when microinjected in 10 micrograms doses into pretectal area of midbrain (A3.5, 3.0, V+1.0 to +1.5 mm) significantly lowered the mean current strength from 640uA to 420uA; clonidine, an alpha-2 agonist in 5 micrograms dose when microinjected into the same locus also significantly lowered the mean current strength to the same level.  

In the pretectal area, posterior thalamic neurons showed intense, Golgi-like immunostaining.  

Bilateral lesions of either the valvula cerebelli or pretectal area completely abolish this visually-guided response, but lesions of the optic tectum have no such effect.  

THir cell bodies were located in the commissural nucleus, nucleus tractus solitarii, the locus coeruleus-subcoeruleus complex, nuclei reticularis superior and inferior, the pretectal area, and substantia nigra.  

Stimulation of the intact eye induced significant cFos expression in various visual centers, including the stratum griseum superficiale of the superior colliculus and the pretectal area, but not in the dLGN, suprachiasmatic nucleus, or retina.  

A few immunoreactive nerve fibers were present in posterior commissure, in the subcommissural organ and pretectal area.  

In the midbrain, TH-IR perikarya were located dorsally in the pretectal area.  

GABAergic projection neurons were found in four distinct subregions of the ZI including: (1) the rostral pole of the ZI, from which neurons project to the supragranular layers of the neocortex (especially layer I); (2) the dorsal subregion of the ZI, where both ascending projections to the neocortex and descending projections to the pretectal area were observed; (3) the ventral subregion of the ZI, whose neurons project to the superior colliculus; and 3) the caudal pole of the ZI, from which descending projections to the lower brainstem and spinal cord were observed.  

Displaceable binding of the label was sharply localized to discrete areas, being high in mamillary nuclei, the arcuate nucleus, nucleus of the solitary tract and the pretectal area, intermediate in the lateral septal nuclei, olfactory bulb, dorsal tegmental nuclei and the interpenduncular nucleus, and low in other regions.  

The postcommissural nucleus and pretectal area contained 5-HT+ and LENK+ cells.  

The nucleus reticularis magnocellularis, reticularis paragigantocellularis lateralis, the ventral met- and mesencephalon (B7 and B9 cell groups), the hypothalamus, and the pretectal area contained additional 5-HT+ and LENK+ cells.  

Single fibers could be followed from the caudal part of the medial habenular nucleus and the pretectal area into the rostral part of the deep pineal gland.  

In both species, dopamine-immunoreactive (DAi) cell bodies were observed in the olfactory bulb, the preoptic area, the suprachiasmatic nucleus, the nucleus of the periventricular organ and its accompanying cells, the nucleus of the posterior tubercle, the pretectal area, the midbrain tegmentum, around the solitary tract, in the ependymal and subependymal layers along the midline of the caudal rhombencephalon, and ventral to the central canal of the spinal cord.  

Smaller changes (15-20%) were detected in the paraventricular nucleus and the pretectal area.  

Each retina projects bilaterally to the suprachiasmatic nucleus, dorsal and ventral lateral geniculate nuclei, pretectal area, and superior colliculus (SC).  

The aim of this study was to corroborate lesioning work (Mackel and Noda 1989), suggesting the pretectal area of the rostral midbrain acts as a relay between the spinal cord and the ventrolateral (VL) nucleus of the thalamus. For this purpose, extracellular recordings were made from neurons in the pretectal area which were antidromically activated by stimulation in the rostral thalamus, particularly in VL. Latencies of the antidromic responses ranged between 0.6 and 3.0 ms (median 1.0 ms): no differences in latencies were associated with either location of the neurons in the pretectal area or with the site of their thalamic projection. Orthodromic responses to stimulation of ascending pathways were seen in the majority of neurons throughout the pretectal area sampled. The data show that neurons of the pretectal area are capable of relaying somatosensory input ascending from the spinal cord to the rostral thalamus.  

The superficial pretectal area was labeled on both sides of the brain.  

In addition, the medial habenular nuclei and the pretectal area contain S-antigen-immunoreactive perikarya, which resemble pinealocytes in size, shape and immunoreactivity and are considered as "pinealocyte-like" epithalamic cells.  

Lesions to 12 of the 37 brain sites investigated (anterior pretectal area, subthalamus, posterolateral hypothalamus, frontocingulate cortex, anterior thalamus, mediodorsal thalamus, ventromedial thalamus, parafascicular nucleus, mamillary bodies, cerebellum, olfactory bulb, and ventromedial hypothalamus) retarded puzzle-box learning.  

Furthermore, labeled neurons were found in the contralateral medial pretectal area in guinea-pigs, in the ipsilateral tegmental mesencephalic reticular formation in monkeys, in the laterodorsal tegmental nucleus in rabbits, and in the dorsal hypothalamic area near the nucleus of the anterior commissure in monkeys.  

Occasional neurons were labeled in the ventral lateral geniculate nuc., pretectal area, and in the solitary nuc.  

Following transection of the lateral forebrain bundle, proenkephalin-like immunoreactivity could no longer be detected on the ipsilateral side of the brain in either the pretectal area or the nuclei of the mesencephalic tegmentum which receive projections from the ipsilateral lateral forebrain bundle.  

Striatal efferents terminated in the pretectal area and in the anterodorsal, anteroventral and posteroventral tegmental nuclei..  

Midbrain changes involved the anterior pretectal area (+8%) and the central gray area (-11%).  

Grafts in this group tended to be poorly formed or were located outside the pretectal area.  

Retinal projections to the hypothalamus, dorsalateral anterior thalamus (rostralateral part, magnocellular part, and lateral part), lateral anterior thalamus, lateroventral geniculate nucleus, lateral geniculate intercalated nuclei (rostral and caudal parts), ventrolateral thalamus, superficial synencephalic nucleus, external nucleus, tectal gray, diffuse pretectal area, pretectal optic area, ectomammillary nucleus, and optic tectum were revealed.  

The heterotopically transplanted neuroepithelia were integrated in the host pretectal area, although their precise location, substituting some missing host pretectal nuclei, varied slightly from case to case.  

Retinal fibers clearly terminate bilaterally in the lateral geniculate nuclei, superior colliculus, pretectal area, and nucleus of the optic tract.  

The morphology of projection neurons in the basal optic nucleus and the pretectal area and the interconnections of these brain regions were studied with the aid of the cobalt-filling technique.  

Sections were then examined under a microscope and some subcortical nuclei including the suprachiasmatic nucleus (SCN), dorsal and ventral lateral geniculate nuclei(dLGN and vLGN), three optic accessory nuclei (i.e., the medial, lateral and dorsal terminal nuclei - MTN, LTN and DTN), the nuclei of the pretectal area(PTN) and the superior colliculus(SC) in the subcortical regions were marked by labeled isotopes.  

After horseradish peroxidase had been applied to the ends of the optic nerves of Sprague-Dawley rats that had been sectioned at their entry into the eyeball, retrogradely labelled neurons were found in the pretectal region (mostly in the contralateral medial pretectal area) and in the ventrolateral area of the contralateral central grey matter at the level of the mesencephalic-metencephalic junction.  

In the pretectal region, labeled terminal patches were consistently found in the nucleus limitans of the posterior thalamus, but we could not determine if label in the nucleus of the pretectal area and dorsal parts of the nucleus of the posterior commissure marked axon terminals or fibers of passage.  

In the rat, a zone of dense retrograde cell labeling and of diffuse axonal labeling occurred in the sub-pretectal area, a region which corresponds to the posterior thalamic nucleus (PT) of Bold et al. In a second set of experiments, 14 rats received a tracer injection (HRP, WGA-HRP or Phaseolus vulgaris-leucoagglutinin) in the sub-pretectal area.  

Rostral efferent projections of the tectum opticum terminated in the ipsilateral pretectal area and the ipsilateral dorsal and ventral thalamus ipsilaterally coursing to the contralateral tectum via the commissura postoptica.  

The highest regional values, as evaluated by the permeability area product technique, were found in cortex, thalamic nuclei, medial geniculate nucleus, anterior pretectal area, paraventricular nucleus of the hypothalamus, choroid plexuses, and bulb-pons.  

Furthermore, S-antigen-immunoreactive, long, axonal processes were observed in the pineal organ and could be traced from the pineal organ to the habenular nucleus and to the pretectal area.  

MAb-A5 antigen is also detectable in the nucleus of Belonci, the corpus geniculatum thalamicum, the pretectal area, and the basal optic nucleus, all targets of the optic nerve, but is not detectable in the optic nerve or the optic tract.  

Agonist inhibition was altered in the central layers of the cerebral cortex and in the pretectal area in scopolamine-treated animals.  

It was shown that stimulation of nucleus reticularis parvocellularis of the medulla oblongata as well as interstitial nucleus of Cajal, nucleus Darkschewitsch, periaqueductal gray and pretectal area evokes in facial motoneurons monosynaptic excitatory postsynaptic potentials accompanied by single action potentials.  

In both series of experiments labeling was seen bilaterally in the suprachiasmatic nucleus, the dorsal and the ventral lateral geniculate nucleus, the superior colliculus, and the pretectal area and contralaterally in the terminal nuclei (dorsal, lateral and medial) of the accessory optic system.  

DYN B cell bodies were present in nonpyramidal cells of neo- and allocortices, medium-sized cells of the caudate-putamen, nucleus accumbens, lateral part of the central nucleus of the amygdala, bed nucleus of the stria terminalis, preoptic area, and in sectors of nearly every hypothalamic nucleus and area, medial pretectal area, and nucleus of the optic tract, periaqueductal gray, raphe nuclei, cuneiform nucleus, sagulum, retrorubral nucleus, peripeduncular nucleus, lateral terminal nucleus, pedunculopontine nucleus, mesencephalic trigeminal nucleus, parabigeminal nucleus, dorsal nucleus of the lateral lemniscus, lateral superior olivary nucleus, superior paraolivary nucleus, medial superior olivary nucleus, ventral nucleus of the trapezoid body, lateral dorsal tegmental nucleus, accessory trigeminal nucleus, solitary nucleus, nucleus ambiguus, paratrigeminal nucleus, area postrema, lateral reticular nucleus, and ventrolateral region of the reticular formation.  

[ 3H]Acetylcholine binding to high affinity muscarinic receptors was similar to what has been described for an M-2 distribution: highest levels of binding occurred in the pontine and brainstem nuclei, anterior pretectal area and anteroventral thalamic nucleus, while lower levels occurred in the caudate-putamen, accumbens nucleus and primary olfactory cortex.  

Suction lesions of the left rostral superior colliculus (SC) and pretectal area were made in young rats.  

Stimulation of periaqueductal gray and pretectal area was found to evoke mono- and polysynaptic activation of facial motoneurons.  

They were especially abundant in its caudal part, lying between the medial geniculate body and the pretectal area.  

Only stimulation in the dorsal hippocampus and pretectal area caused antinociception without significant aversion.  

Labelled fibres and "terminal-like" labelling were found in the anterior pretectal area, in the thalamic parafascicular nucleus, in the posterior nucleus and the ventroposterior complex, in the zona incerta and in the fields of Forel, but none were observed in the supraoptic or paraventricular nuclei.  

Retrogradely filled neurons were observed in two locations: the medial pretectal area and the contralateral periaqueductal grey matter, indicating that the pretectum and the mesencephalon are sources of centrifugal innervation to the rat retina..  

The retinal fibers terminate bilaterally in the following places: suprachiasmatic nucleus, dorsolateral optic nucleus, optic nucleus of the posterior commissure, cortical nucleus, ventral pretectal area, optic tectum, and the accessory optic terminal field.  

Scant but consistent labeling occurred in the cingular, retrosplenial, and insular cortices, within the medial forebrain bundle, fields of Forel, zona incerta, ventral tegmental area of Tsai, substantia nigra, pretectal area, periaqueductal gray, dorsal tegmental nucleus, locus ceruleus, and raphe complex.  

Specific binding of [ 3H]flunitrazepam in the central nervous system of the spastic mouse showed significant increases in the anterior colliculus and pretectal area and in all laminae of the grey matter in the lumbar spinal cord.  

In contrast, the mesencephalic nuclei, probably linked to the mesencephalic tectum and the pretectal area, appears to be a coordinating apparatus between the visual system and the trunk/tail musculature.  

Neurons in this size range are also unlabeled after injection of retrograde tracer in the pretectal area, inferior and superior colliculi, inferior olivary complex, and/or spinal cord.  

In both species, HRP-labeled axons were observed in the habenular nuclei, the pretectal area, the dorsal and ventral thalamus, the dorsal periventricular tegmentum, and in the posterior periventricular hypothalamus. Thin, varicose (preterminal) axons were observed in great numbers in the pretectal area and dorsal thalamus in both species, and in small numbers in the habenular nuclei and posterior periventricular hypothalamus. A close association of retinal and pineal terminal fields were noted in the pretectal area and the dorsal thalamus, whereas other diencephalic retinal and pineal recipient areas seem more segregated..  

A rudimentary topography also exists in the pretectum where the dorsal pretectal area receives projections primarily from the ventral retina and the ventral pretectal area receives projections mostly from the dorsal retina.  

Special attention was paid to the terminals in the pretectal area of both the pigmented and albino strains. Ipsilateral projection was not found in the albinos in the pretectal area.  

Serotonin-containing neurons were found in the pretectal area..  

Receptors were concentrated in the olfactory bulb, in the superficial laminae of the primary olfactory cortex, in the deep laminae of the cerebral cortex, and in the pretectal area.  

Synaptic inputs of rubrospinal (RN) neurons from the cerebral cortex, pretectal area (PRT), and medial lemniscus (ML) were investigated electrophysiologically in the cat.  

The effects of various lesions in the accessory optic system and pretectal area were studied on the horizontal optokinetic head nystagmus (OKN) in the frog Rana esculenta.  

In addition, somatostatin-immunoreactive neurons were demonstrated in the magnocellular preoptic, entopeduncular and dorsolateral thalamic nuclei, further in the pretectal area and the ventrolateral tegmentum.  

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).  

The most superficial layers of superior colliculus (SC) and a pretectal area including the nucleus of the optic tract (NOT) appear symmetrically, strongly darker than other visual structures such as lateral geniculate nucleus (LGN) and visual cortex (VC). Whereas the lack of metabolic increase at LGN and VC levels entirely confirms the non-involvement of the geniculo-cortical path in mediating the optomotor response following OKS in Rodents, it is postulated that the symmetrical increase of 2DG uptake even upon unidirectional OKS found even at pretectal level may represent a commissural transfer of visual information between homologous pretectal areas like the nuclei of the optic tract..  

Nucleus rotundus receives an input from the tectum mesencephali, the pretectal area, and from the mesencephalic reticular formation.  

It was evident that among the entire scope of its inputs, the FEF received a prominent afferent projection from the nucleus of the optic tract (NOT, nucleus limitans) and the suprageniculate nucleus, and projected to a medial subdivision of NOT, sublentiform nucleus, nucleus of the pretectal area, nucleus of the posterior commissure, and the rostral periaqueductal gray.  

Diencephalic projections to the tectum originate from the thalamus dorsalis pars medialis, the thalamus ventralis pars lateralis, the nucleus medius infundibuli, and the pretectal area.  

(5) Lamina IX projects to a dorsal pretectal area.  

Projections were found to pretectal area, dorsal thalamus, basal optic nucleus, and optic tectum, all at the contralateral side.  

In this study subcortical projections of the pulvinar have been seen to terminate in the superior colliculus, pretectal area, and the following thalamic nuclei: posterior, suprageniculate, dorsolateral, posterolateral, reticular, centromedian, centrolateral, parafascicular and dorsomedial.  

Nonretinal sources of tectal afferents, the laminar and regional organization of the inputs, and the relation of the tectum with primary and secondary visual and motor centers in goldfish were studied following HRP injections in the optic tectum, orbit of the eye, cerebellum, pretectal area, and dorsolateral mesencephalic tegmentum. Cells of origin of extrinsic tectal efferents were also identified following HRP injections in the pretectal area and mesencephalic tegmentum.  

After a unilateral lesion made through all six tectal layers, three distinct pathways could be observed: 1) an ascending projection both ipsi- and contralateral to the pretectal area, the dorsomedial region of the thalamus, and the lateral geniculate body, 2) a commisural projection to the contralateral tectum and intercollicular nucleus, and 3) a descending projection to the rhombencephalic reticular formation.  

Whereas this pathway exhibits a striking asymmetry at the level of the habenular ganglia, its projections to the dorsolateral nucleus of the thalamus, the periventricular hypothalamic area, the preoptic hypothalamic and telencephalic regions, and the pretectal area are arranged in a strictly symmetric manner.  

On the other hand, HRP injections of the ventromedial portion of the midbrain tegmentum (including the red nucleus), the superior colliculus, the pretectal area or a midbrain region at the lateral border of the central gray substance resulted in retrograde labeling of cells in the zona incerta, but no labeled cells appeared in these cases in the ventrally adjacent STN.  

Horseradish peroxidase (HRP) labeled neuronal somas were consistently found in the medial pretectal area after intraocular injection of HRP.  

Retinal fibres partially decussate in the chiasma, and terminate on both sides in the nucleus ovoidalis, lateral geniculate complex, pretectal area, optic tectum, and in the basal optic nucleus.  

After injection of the enzyme in the pulvinar, neurons were labeled in all subdivisions of the pretectal area. The possible role of the pretectal area and superior colliculus in mediating somesthetic input to the pulvinar and lateralis posterior, respectively, and the role of these structures in the control of ocular movements, are discussed..  

Sparse addition LHb projections pass to the pretectal area, superior colliculus, nucleus reticularis tegmenti pontis, parabrachial nuclei and locus coeruleus.  

In other brain structures (lateral ventrothalamic nucleus, in the pretectal area--cortical nucleus, pretectal nucleus, posterior comissure nucleus) the density of degeneration of optic fibers was significantly lower.  

HRP injections into the pretectal area, lateral geniculate body, suprachiasmatic nucleus and lateral hypothalamic area resulted in the labeling of neurons in the middle subgroup only when the supraoptic commissure and optic tract were injured by a pipette used in injections.  

Visual structures: ventral lateral geniculate nucleus, parabigeminal nucleus, pretectal area (nucleus of the optic tract, posterior pretectal nucleus, nuclei of the posterior commissure).  

After injection of horseradish peroxidase into the frontal organ of Rana temporaria, labeled perikarya were found in the medial part of the amygdala, the preoptic area, the nucleus rotundus, the pretectal area, and the lateral parts of the midbrain central griseum..  

HRP label in the pretectal area was strictly confined to the olivary nucleus and the corresponding pathway seems to concern the Edinger-Westphal nucleus in particular.  

The light reflex is conveyed by slow (less than 10 m/sec) optic tract fibres which synapase in the medial part of the pretectal area.  

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. Only the parabigeminal nucleus and the pretectal area showed labeled cells following injections in the superficial layers of the superior colliculus. In some cases, HRP-positive cells were seen in the nucleus of posterior commissure, the pretectal area, Forel's field, and nucleus reticularis thalami.  

Stimulation of sites in the caudal thalamus and pretectal area yielded analgesia without stimulation-induced aversive reactions, confirming the potential of these sites for use in the relief of clinical pain in man..  

HRP positive cells in the pretectal area, nuclei of the posterior commissura and mesencephalic ventro-lateral tegmentum were observed only in cases when the enzyme was diffused from the injection site into the neostriatum, while the HRP retrograde transport to n.  

Subcortical sites with labeled neurons included the necleus basalis of the substantia innominata, the claustrum, the pulvinar and intralaminar thalamic nuclei, the pretectal area, the nucleus locus coeruleus and the raphe nuclei.  

Bilateral ascending projections reach the pretectal area, nucleus lentiformis mescencephali, lateral habenular nuclei, and posterodorsal nuclei.  

subthalamicus, pretectal area, colliculus superior and griseum pontis as well as the ipsi- and contralateral n.  

Conditioning electrical stimuli were applied to the flocculus, the inferior olive, and optic pathways at the retinae, optic chiasm, pretectal area and upper medulla. The two reflexes from the horizontal canal were depressed by stimulation of the ipsilateral optic pathway which reached the ipsilateral flocculus via the contralateral pretectal area and inferior olive. One was depressed from the contralateral retina via the ipsilateral pretectal area, while another was depressed from the ipsilateral retina via the contralateral pretectal area, though only occasionally. The third reflex was depressed from the ipsilateral pretectal area but not from the retina. The fourth was affected from neither the retina nor the pretectal area.  

Following neonatal lesion in the sensorimotor and adjacent cortex (SMC) in the albino rats, a corresponding region in the contralateral intact cortex gave rise to a bilateral corticofugal projection to the pretectal area, superior colliculus, pons, gracile and cuneate nuclei, the nucleus of Bischoff, caudal medullary reticular formation and the spinal cord. The anomalous fibres reached their specific target cells either by deflecting ipsilaterally at the pyramidal decussation to reach the spinal cord and the caudal medulla or by running across the mid-line to the contralateral pons, superior colliculus, pretectal area and the thalamic ventrobasal complex.  

Throughout the ascending course of the path from the locus coeruleus, axons were given off to the pretectal area, the medial and lateral geniculate nuclei and the amygdala; fibers passed contralaterally through the posterior commissure, the midline thalamus, and the supraoptic commissure.  

These include the caudate-putamen, nucleus accumbens, globus pallidus, olfactory tubercle, subthalamic nucleus, substantia nigra, pretectal area, third, fourth and sixth cranial verve nuclei, and the trapezoid body nucleus..  

There were two dorsomedial projections: (1) a projection to the superior colliculus which terminated mainly in the medial third of the stratum opticum, and (2) a large projection via the superior thalamic radiation which terminated in the ipsilateral pretectal area; a continuation of this projection passed through the posterior commissure to attain the contralateral pretectal area.  

Cholesterol implanted into the same area, or similar amounts of testosterone propionate implanted into the posterior hypothalamus/pretectal area (4 females) or cerebral cortex/dorsal thalamus (5 monkeys) had no consistent effect on behaviour.  

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