Cells in the pretectal olivary nucleus are in the pathway for the direct light reflex of the pupil in the rat

Trejo, Leonard J.; Cicerone, Carol M.

doi:10.1016/0006-8993(84)91340-4

Cited by 146 publications

(92 citation statements)

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“…A further group of 12 animals was used to examine whether targets other than the SC exert different effects on subsets of neurons. To this purpose, we reconnected the axotomized and MIF-treated retina with the pretectum (Thanos, February 1995February , 15(2) 1059 1992) the primary visual afferent center that subserves the pupillary constriction reflex and which normally receives about 13% of the retinofugal axons (Hultborn et al, 1978;Trejo and Cicerone, 1984;Clarke and Ikeda, 1985). This group will be referred to as "PT-reconnected" group throughout this paper.…”

Section: Methodsmentioning

confidence: 99%

“…Target-dependent appearance of regenerating ganglion cells in PT-reconnected retinas A small subpopulation of about 13% of the retinofugal axons, which belong to large type I cells, terminates within the pretecturn, and in particular within the nucleus olivaris pretectalis (Hultborn et al, 1978;Trejo and Cicerone, 1984) which subserves the light-induced constriction of the pupil as response to illumination. In a previous investigation (Thanos, 1992), guidance of the retinal contingent of regenerating axons into this area was used to restore the interrupted circuitry of the pupillary reflex in adult rats and documented that the formation of functional synapses is, in principle, possible.…”

Section: Morphometry and Classification Of Regenerating Ganglion Cellsmentioning

confidence: 99%

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Type-specific stabilization and target-dependent survival of regenerating ganglion cells in the retina of adult rats

Thanos

Mey

1995

J. Neurosci.

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Axotomy-induced degradation of retinal ganglion cells (RGC) can be delayed if the destructive features of activated microglial cells are pharmacologically neutralized, and prevented if the axons are permitted to regrow into transplanted autologous peripheral nerve (PN) pieces. This study was undertaken to classify the regenerating rat RGC and to examine target-dependent effects on survival of subsets of neurons. In analogy to the normal rat retina, we have categorized the retrogradely labeled, regenerating RGC into five classes which are morphologically distinct and reminiscent of normal RGC correlates (types I, II, III, delta-cells, and displaced RGC). Six weeks after transplantation of peripheral nerve to the transected optic nerve, large, type I-like cells (RI) constituted 5.7 +/- 2.0% of the total population. Smaller, round to oval cells of type RII represented the majority of labeled neurons (64.5 +/- 6.1%). Cells of type RIII constituted 4.6 +/- 1.7% of the total population and had very typical, middlesized, polarized perikarya and large dendrites. Less frequent (< 1%) were R-delta and displaced RGC. Transplantation of a PN graft which was not reconnected with a central target (blind-ending group) and monitoring of the extant neurons showed a progressive disappearance of the regenerating RGC, such that 6 months after surgery predominantly few large cells survived. When the retinas were treated with macrophage/microglia- inhibiting factor (MIF), and the regenerating axons were guided into the pretectum, predominantly large RGC of type RI survived. Guidance of the axons into their major natural target, the superior colliculus (SC), resulted in selective survival of many small, RII-like RGC. Calculation of the dendritic coverage factors for the major types of RGC revealed that dendrites of the most abundant small cells of type RII overlapped uniformly and covered the retinal surface completely, whereas cells of types RI and RIII did not suffice for surface coverage. The results suggest that combined suppression of axotomy- induced microglial activation and guidance of regenerating axons with a PN graft into central targets is a suitable technique to produce sufficient numbers of regenerating axons which may retrieve some functional properties. Target-specific neuronal contacts are likely involved in morphological stabilization and better survival of regenerating neurons.

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Section: Methodsmentioning

confidence: 99%

Section: Morphometry and Classification Of Regenerating Ganglion Cellsmentioning

confidence: 99%

Type-specific stabilization and target-dependent survival of regenerating ganglion cells in the retina of adult rats

Thanos

Mey

1995

J. Neurosci.

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“…Neurons in both IGL and OPN encode ambient light levels (32-34), a property almost certainly conferred by the photosensitive RGCs, which faithfully report retinal irradiance (12). Like the SCN, the IGL and the VLG are implicated in circadian photoentrainment (32), whereas the OPN is a key node in the circuit mediating the pupillary light reflex (33,34), another non-image-forming visual function. Indeed, rodless and coneless mice retain a pupillary light response (2), with the spectral tuning and high thresholds expected for a response driven by the intrinsically photosensitive RGCs (12).…”

mentioning

confidence: 99%

Melanopsin-Containing Retinal Ganglion Cells: Architecture, Projections, and Intrinsic Photosensitivity

Hattar

Liao

Takao

et al. 2002

Science

2,319

1,941

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The primary circadian pacemaker, in the suprachiasmatic nucleus (SCN) of the mammalian brain, is photoentrained by light signals from the eyes through the retinohypothalamic tract. Retinal rod and cone cells are not required for photoentrainment. Recent evidence suggests that the entraining photoreceptors are retinal ganglion cells (RGCs) that project to the SCN. The visual pigment for this photoreceptor may be melanopsin, an opsin-like protein whose coding messenger RNA is found in a subset of mammalian RGCs. By cloning rat melanopsin and generating specific antibodies, we show that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs. In mice heterozygous for tau-lacZ targeted to the melanopsin gene locus, β-galactosidase-positive RGC axons projected to the SCN and other brain nuclei involved in circadian photoentrainment or the pupillary light reflex. Rat RGCs that exhibited intrinsic photosensitivity invariably expressed melanopsin. Hence, melanopsin is most likely the visual pigment of phototransducing RGCs that set the circadian clock and initiate other non-image-forming visual functions.Retinal rods and cones, with their light-sensitive, opsin-based pigments, are the primary photoreceptors for vertebrate vision. Visual signals are transmitted to the brain through RGCs, the output neurons whose axons form the optic nerve. This system, through its projections to the lateral geniculate nucleus and the midbrain, is responsible for interpreting and tracking visual objects and patterns. A separate visual circuit, running in parallel with this imageforming visual system, encodes the general level of environmental illumination and drives certain photic responses, including synchronization of the biological clock with the light-dark cycle (1), control of pupil size (2), acute suppression of locomotor behavior (3), melatonin release (4), and others (5-7). Surprisingly, this non-image-forming system does not appear to originate from rods and cones. For example, rods and cones are not required for photoentrainment of circadian rhythms (8), a function mediated by the retinohypothalamic tract (9,10) and its target, the SCN, the brain's circadian pacemaker (1). Nor are rods and cones necessary for the pupillary light reflex, mediated by the retinal projection to the pretectal region of the brainstem (2). At present, the best candidate for a photopigment is an opsin-like protein † To whom correspondence should be addressed. kwyau@mail.jhmi.edu. * These authors contributed equally to this work. called melanopsin, which is expressed by a subset of mouse and human RGCs (11). The accompanying report (12) shows that RGCs projecting to the SCN are directly sensitive to light. Thus, melanopsin may be the photopigment responsible for this intrinsic photosensitivity, and it may also trigger other non-image-forming visual functions. NIH Public AccessWe cloned the full-length cDNA for rat melanopsin (13), on the basis of homology to mouse melanopsin (11). The predicted amino...

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“…LA). The reflex is abolished by destruction of the pretectal nuclear complex (11), and specific stimulation of tonic "on" cell clusters in the olivary pretectal nucleus leads to pupilloconstriction (4). In this study we have examined whether a reflex response can be elicited in the eye of a host rat by illuminating a retinal transplant placed over the brain stem.…”

mentioning

confidence: 99%

“…One such system is the pupillary reflex. In intact animals, this is mediated through a subdivision of the pretectum, the olivary pretectal nucleus (4,5). This receives optic input and projects directly or indirectly to the Edinger-Westphal nucleus of the oculomotor complex, which in turn innervates the eye through the ciliary ganglion (refs.…”

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confidence: 99%

Retinal transplants can drive a pupillary reflex in host rat brains.

Klassen

Lund²

1987

Proc. Natl. Acad. Sci. U.S.A.

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Retinae taken from embryonic rats were transplanted over the midbrain of neonatal rats, from whom one eye had been removed. After 5 months, the optic nerve of the remaining eye was cut, and the transplant was exposed. Illumination of the transplant caused pupilloconstriction of the host eye, a response abolished by damaging the transplant. Thus neural transplants are capable of driving specific reflexes in response to natural stimuli.Various studies have shown behavioral recovery following transplantation of embryonic tissue to the brains of mammals with neurological deficits resulting from specific lesions or genetic disorders (1). In all these cases, the essential function of the transplant seems to be to produce an appropriate chemical in approximately the correct location. The donor cells need not be the normal ones innervating the region: adrenal medulla, for example, may serve as an alternative source to substantia nigra of dopamine-producing cells (2). The connections made between transplanted cells and host brain also need not be normal for functional recovery to occur (14).A second role for neural transplants that has so far received much less attention is to mediate functions that require precise patterns of connections as their substrate. One such system is the pupillary reflex. In intact animals, this is mediated through a subdivision of the pretectum, the olivary pretectal nucleus (4, 5). This receives optic input and projects directly or indirectly to the Edinger-Westphal nucleus of the oculomotor complex, which in turn innervates the eye through the ciliary ganglion (refs. 6-10; Fig. LA). The reflex is abolished by destruction of the pretectal nuclear complex (11), and specific stimulation of tonic "on" cell clusters in the olivary pretectal nucleus leads to pupilloconstriction (4). In this study we have examined whether a reflex response can be elicited in the eye of a host rat by illuminating a retinal transplant placed over the brain stem. METHODSRetinae were dissected from rat embryos of 13 days of gestation and transplanted over the superior colliculus of neonatal rats, as described (12). Effort was made to place the transplants either just caudal to the pretectum or more caudally such that they would ultimately come to lie over the cerebellum and be readily accessible for experimentation. The right eye was removed at the time of transplantation to ensure a heavier innervation of the subcortical visual centers by the transplant (12). After 5 months, the optic nerve of the remaining eye was sectioned intracranially to prevent relay of visual information to the brain from that eye but to maintain intact the parasympathetic outflow to the eye carried in the oculomotor nerve. Two days later, the transplant was exposed either by drilling off the bone over the cerebellum (posterior location) or by removing the bone, occipital cortex, and hippocampus on both sides to expose the midbrain (anterior location). The experimental preparation is shown schematically in Fig. 1 B and C

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Cells in the pretectal olivary nucleus are in the pathway for the direct light reflex of the pupil in the rat

Cited by 146 publications

References 28 publications

Type-specific stabilization and target-dependent survival of regenerating ganglion cells in the retina of adult rats

Type-specific stabilization and target-dependent survival of regenerating ganglion cells in the retina of adult rats

Melanopsin-Containing Retinal Ganglion Cells: Architecture, Projections, and Intrinsic Photosensitivity

Retinal transplants can drive a pupillary reflex in host rat brains.

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