The pathway and mechanism of convergence movement of eyes are not exactly confirmed at now. But, according to the recent neurophysiologic studies, the convergence cells was found in an area of the mesencephalic reticular formation just dorsal and lateral to the oculomotor nucleus and rostral to the superior colliculus. I experienced four patients, who complained diplopia due to unilateral convergence palsy. These cases of unilateral convergence palsy suggests that the Rt. Convergence cells and the Lt. Convergence cells in the mesencephalic reticular formation has independent pathway to ipsialteral medial rectus motoneuron nucleus.
Diplopia ; Humans ; Paralysis* ; Reticular Formation ; Superior Colliculi

The superior colliculus (SC), one of the most well-characterized midbrain sensorimotor structures where visual, auditory, and somatosensory information are integrated to initiate motor commands, is highly conserved across vertebrate evolution. Moreover, cell-type-specific SC neurons integrate afferent signals within local networks to generate defined output related to innate and cognitive behaviors. This review focuses on the recent progress in understanding of phenotypic diversity amongst SC neurons and their intrinsic circuits and long-projection targets. We further describe relevant neural circuits and specific cell types in relation to behavioral outputs and cognitive functions. The systematic delineation of SC organization, cell types, and neural connections is further put into context across species as these depend upon laminar architecture. Moreover, we focus on SC neural circuitry involving saccadic eye movement, and cognitive and innate behaviors. Overall, the review provides insight into SC functioning and represents a basis for further understanding of the pathology associated with SC dysfunction.
Superior Colliculi/physiology* ; Saccades ; Neurons/physiology*

The distribution and morphology of cholecystokinin-8 (CCK 8)-, neuropeptide Y (NPY)-, Substance P (SP)- and vasoactive intestinal polypeptide (VIP)-immunoreactivity were examined in the cat superior colliculus (SC) by means of immunohistochemistry. Judging from this study, some neuropeptides-IR neurons may be present in the superficial layers of the sc. And these neurons and neuropeptides may be involved in the functions of the superficial layers.
Animals ; Brain* ; Cats* ; Immunohistochemistry ; Neurons* ; Neuropeptide Y ; Neuropeptides ; Substance P ; Superior Colliculi* ; Vasoactive Intestinal Peptide

PURPOSE: To investigate the change of the Beta adrenergic system in the rat visual cortex and superior colliculus after visual deprivation during a critical period of postnatal development. METHODS: The changes of beta 1 and beta 2 adrenergic receptor mRNA were investigated by using northern blot analysis in the rat visual cortex and superior colliculus. The right eyelid of visually deprived rat was sutured at the 10th postnatal days. After visual deprivation for 4 weeks, the rat were sacrificed and the visual cortex and superior colliculus tissues were removed for analysis. RESULTS: Beta 1 and beta 2 adrenergic receptor mRNA expression was decreased in the contralateral visual cortex to the deprived eye. In the superior colliculus, beta 2 adrenergic receptor mRNA expression increased in both sides, but a much greater increase was shown in the ipsilateral superior colliculus than the contralateral side. CONCLUSIONS: These results suggests that visual deprivation during a critical period of postnatal development influences the beta adrenergic system in the rat visual cortex and superior colliculus.
Animals ; Blotting, Northern ; Critical Period (Psychology) ; Eyelids ; Rats* ; Receptors, Adrenergic ; RNA, Messenger* ; Superior Colliculi* ; Visual Cortex*

EphA/ephrin-A mediated signaling has emerged as a key mechanism regulating axon guidance and topographic mapping, particularly in the well-characterized visual system from the retina to the superior colliculus (SC). In this study, EphA8 bacterial artificial chromosome (BAC) was manipulated to contain a floxed eGFP and human ephrin-A5 expression cassette using homologous recombination method. In the mice containing the recombinant BAC, it was shown that GFP is expressed in an anterior>posterior gradient in the SC. Furthermore, when these mice were crossed with the transgenic mice expressing Cre under the EphA8 promoter, it was evident that a GFP expression cassette was eliminated, and that human ephrin-A5 was ectopically expressed in the anterior region of the SC. This transgenic model would be useful to analyze the role of ephrin-A5 in the SC during the retinocollicular topography formation.
Animals ; Axons ; Chromosomes, Artificial, Bacterial ; Ephrin-A5 ; Homologous Recombination ; Humans ; Mice ; Mice, Transgenic ; Retina ; Superior Colliculi

Environmental threats often trigger innate defensive responses in mammals. However, the gradual development of functional properties of these responses during the postnatal development stage remains unclear. Here, we report that looming stimulation in mice evoked flight behavior commencing at P14-16 and had fully developed by P20-24. The visual-evoked innate defensive response was not significantly altered by sensory deprivation at an early postnatal stage. Furthermore, the percentages of wide-field and horizontal cells in the superior colliculus were notably elevated at P20-24. Our findings define a developmental time window for the formation of the visual innate defense response during the early postnatal period and provide important insight into the underlying mechanism.
Animals ; Evoked Potentials, Visual ; Fear/physiology* ; Mammals ; Mice ; Mice, Inbred C57BL ; Neurons/physiology* ; Superior Colliculi/physiology*

In order to present the optimal neuroscience tutorial material for medical students and researchers, this study is aimed to make neuro-digital slide and neuro-atlas based on the histological specimens of human spinal cord and brain stem. Cadavers which had agreed for organ donation for research purpose were used in this study. Brains and spinal cords were extracted within 24 hours after death, and then fixed with 10% neutral buffered formalin. Paraffin blocks were made with the following regions; 8 regions from the spinal cord (the levels of the upper cervical segment, the cervical enlargement, the upper thoracic segment, the mid thoracic segment, the lower thoracic segment, the upper lumbar segment, the lumbar enlargement, the sacral segment), 14 regions from the brain stem (the levels of the spinomedullary junction, the pyramidal decussation, the medial lemniscus decussation, the obex, the mid-olivary medulla, the upper medulla, the pontomedullary junction, the lower pons, the mid pons, the upper pons, the isthmus rhombencephali, the inferior colliculus, the superior colliculus, the posterior commissure). Using virtual microscope software, we made digital neuro-slides which can be used anywhere and anytime regardless of equipment of microscope. To help understanding anatomy and functions of nervous tissue, we also made neuro-atlas based on the digital slide images. As results, the outline and detailed structures of nuclei and tracts are easily discriminated and also matched with marks and nomenclatures of neuro-atlas. Moreover, the cytoarchitecture of each nucleus and histological features can be well distinguished. We hope that this product would be used as a useful neuroscience tutorial material for the medical and paramedical school students, clinical trainees like interns and residents, and also neuroscience researchers.
Brain ; Brain Stem ; Formaldehyde ; Humans ; Inferior Colliculi ; Neurosciences ; Paraffin ; Pons ; Pyramidal Tracts ; Spinal Cord ; Students, Medical ; Superior Colliculi ; Tissue and Organ Procurement

Nitric oxide is synthesized by neurons containing the nitric oxide synthase (NOS), and the nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) is a selective histochemical marker for the brain. Although, many reports have been published describing in detail the distribution of NADPH-d and tyrosine hydroxylase (TH), little information is available on possible morphological changes of NADPH-d and TH containing neurons during aging of the brain stem. Therefore, in this study, we assessed the effects of aging on the somal area and staining intensity of NADPH-d-positive and TH-immunoreactive (TH-IR) neurons in rat brain stem. In previous studies, enzyme activities of nitric oxide synthase (NOS) and NADPH-d were shown to be in an almost perfect correlation in the brain. Therefore, we evaluated the change of NADPH-d-positive neurons using a microdensitometrical method as a way of measuring changes in NOS activity. By using a double-labelling technique, we have shown that these two enzymes are located in separate neurons in most brain stem nuclei. In the aged group, the size of NADPH-d-positive neurons was not significantly changed in most nuclei of the brain stem compared to the control group. Staining intensity of NADPH-d-positive neurons was significantly changed in periaqueductal gray, superior colliculus and inferior colliculus in the aged group. In the aged rats, the size of TH-IR neurons was significantly changed in locus ceruleus and lateral paragigantocellular nucleus. Staining intensity of TH-IR neurons was significantly decreased in principal trigeminal nucleus, locus ceruleus and lateral paragigantocellular nucleus of the aged group. These results demonstrate that the NADPH-d-positive and TH-IR neurons are differently influenced by aging than the control group in the brain stem of rats. Difference in the changes of NADPH-d-positive neurons in brain stem nuclei suggest that neuronal NOS is regulated by different mechanims in the regions of the brain stem during aging.
Aging* ; Animals ; Brain Stem* ; Brain* ; Inferior Colliculi ; Locus Coeruleus ; NAD ; Neurons* ; Nitric Oxide ; Nitric Oxide Synthase ; Periaqueductal Gray ; Rats* ; Superior Colliculi ; Trigeminal Nuclei ; Tyrosine 3-Monooxygenase ; Tyrosine*

To investigate the applicability of the Bartha strain of pseudorabies virus(PRV-Ba) as a neurotracer in the visual system, we performed immunohistochemical study of the rat brain after intravitreal injection of the PRV-Ba. Cholera toxin-horseradish peroxidase(CT-HRP), a well known neurotracer, was also injected into the vitreous cavity for comparison. After given survival time the brain was removed and processed immunohistochemical stain for PRV-Ba and neurohistochemical stain for CT-HRP. The CT-HRP positive reactions were observed almost contralaterally in optic chiasm, optic tract, suprachiasmatic nucleus(SCN), olivary pretectal nucleus(OPT), all three subdivision of lateral geniculate body, superficial gray layer and optic layer of superior colliculus and medial, lateral, dorsal terminal nucleus of accessory optic tract. PRV-Ba immunopositive reaction was observed in SCN and OPT, but not in nerve fiber system and dorsal lateral geniculate body. Also PRV-Ba positive cells were distributed mainly in intermediate layer and weakly distributed in superficial layer of the superior colliculus. This study suggests that PRV-Ba is not a useful neurotracer in studying the visual system of the rat.
Animals ; Brain ; Cholera ; Geniculate Bodies ; Herpesvirus 1, Suid* ; Intravitreal Injections ; Nerve Fibers ; Optic Chiasm ; Pseudorabies* ; Rats* ; Superior Colliculi ; Visual Pathways

Acetylcholine is one of the major neurotransmitters in visual system of rats. Cholinergic, serotonergic and gamma-aminobutyric acid(GABA) ergic projections are known as modulators of visual processing. The purpose of this study was to examine the effects of unilateral orbital enucleation on the amount of acetylcholine and its receptor bindings in dorsolateral geniculate body, superior colliculus and visual cortex of rats, and on motor activites. The amount of acetylcholine was measured by gas chromatography; whereas [3H]quinuclidinyl benzilate(QNB) bindings to muscarinic receptors were examined by autoradiography. Motor activity was measured by activity meter for 24 hours. The results of this study were as follows: 1. The amount of acetylcholine in superior colliculus significantly increased at 1 week after enucleation, but it decreased at 2 and 4 weeks after enucleation. In visual cortex, the amount of acetylcholine did not change at 1 week after enucleation, but it significantly decreased at 2 and 4 weeks after enucleation. 2. After enucleation, [3H]-QNB binding to muscarinic receptors gradually decreased over the 4 weeks in dorsolateral geniculate body, superior colliculus and visual cortex. 3. Locomotor activity of rats did not show any change at 1 week after enucleat ion, but it decreased at 2 and 4 weeks after enucleation. In conclusion, unilateral orbital enucleation resulted in a reduction in the amount of acetylcholine and muscarinic receptors in rat visual system, which was speculated to be a major cause of a decrease in physical activity.
Acetylcholine* ; Animals ; Autoradiography ; Chromatography, Gas ; Motor Activity* ; Neurotransmitter Agents ; Orbit* ; Rats* ; Receptors, Muscarinic* ; Superior Colliculi ; Visual Cortex ; Visual Pathways*