Requirement of early postnatal apoptosis in the retina and superior colliculus for normal development of the visual system in mice

AbstractRepetitive visual stimulation is successfully used in a study on the visual evoked potential (VEP) plasticity in the visual system in mammals. Practicing visual tasks or repeated exposure to sensory stimuli can induce neuronal network changes in the cortical circuits and improve the perception of these stimuli. However little is known about the effect of visual training at the subcortical level. In the present study, we extend the knowledge showing positive results of this training in the rat’s superior colliculus (SC). In electrophysiological experiments, we showed that a single training session lasting several hours induces a response enhancement both in the primary visual cortex (V1) and in the SC. Further, we tested if collicular responses will be enhanced without V1 input. For this reason, we inactivated the V1 by applying xylocaine solution onto the cortical surface during visual training. Our results revealed that SC’s response enhancement was present even without V1 inputs and showed no difference in amplitude comparing to VEPs enhancement while the V1 was active. These data suggest that the visual system plasticity and facilitation can develop independently but simultaneously in different parts of the visual system.

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Daily orexinergic modulation of the rat superficial layers of the superior colliculus – implications for intrinsic clock activities in the visual system

10.1101/2021.02.20.432093 ◽

2021 ◽

Author(s):

Lukasz Chrobok ◽

Jagoda Stanislawa Jeczmien-Lazur ◽

Monika Bubka ◽

Kamil Pradel ◽

Aleksandra Klekocinska ◽

...

Keyword(s):

Visual System ◽

Superior Colliculus ◽

Visual Information ◽

Clock Genes ◽

Brain Area ◽

Active Phase ◽

Visual Hallucinations ◽

Tract Tracing ◽

Molecular Approaches ◽

Circadian Expression

AbstractThe orexinergic system delivers excitation for multiple brain centres to facilitate behavioural arousal, with its malfunction resulting in narcolepsy, somnolence, and notably, visual hallucinations. Since the circadian clock underlies the daily arousal, a timed coordination is expected between the orexin system and its target subcortical visual system, including the superior colliculus (SC). Here, we use a combination of electrophysiological, immunohistochemical, and molecular approaches across 24 h, together with the neuronal tract tracing methods in rodents to elucidate the daily coordination between the orexin system and the superficial layers of the SC. We find the daily orexinergic innervation onto the SC, coinciding with the daily silencing of spontaneous firing in this visual brain area. We identify autonomous daily and circadian expression of clock genes in the SC, which may underlie these day-night changes. Additionally, we establish the lateral hypothalamic origin of orexin innervation to the SC and that the SC neurons robustly respond to orexin A via OX2 receptor in both excitatory and GABAA receptor-dependent inhibitory manners. Together, our evidence supports that the clock coordination between the orexinergic input and its response in the SC provides arousal-related excitation needed to detect sparse visual information during the behaviourally active phase.

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Postembryonic development of the visual system of the locust, Schistocerca gregaria

Development ◽

10.1242/dev.46.1.147 ◽

1978 ◽

Vol 46 (1) ◽

pp. 147-170

Author(s):

Hilary Anderson

Keyword(s):

Visual System ◽

Temporal Relationship ◽

Compound Eye ◽

Normal Development ◽

Schistocerca Gregaria ◽

Postembryonic Development ◽

Inductive Interaction ◽

Topographical Mapping

In the compound eye of the locust, Schistocerca gregaria, neurons from the retina project to the lamina in a precise topographical mapping. The formation of this projection was investigated in grafting experiments which altered the spatial or temporal relationship between the retina and the lamina. The results show that retina axons tend to grow along the paths of adjacent axons, with no indication of specificity for their normal termination sites. It is suggested that the orderly sequence of retina differentiation during normal development plays a major role in imposing pattern both upon the developing projection and, through some form of inductive interaction between retina and lamina neurons, upon the lamina.

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Neonatal Cortical Ablation Disrupts Multisensory Development in Superior Colliculus

Journal of Neurophysiology ◽

10.1152/jn.00880.2005 ◽

2006 ◽

Vol 95 (3) ◽

pp. 1380-1396 ◽

Cited By ~ 27

Author(s):

Wan Jiang ◽

Huai Jiang ◽

Barry E. Stein

Keyword(s):

Superior Colliculus ◽

Normal Development ◽

Receptive Fields ◽

Early Ontogeny ◽

Neonatal Brain ◽

Anterior Ectosylvian Sulcus ◽

Cortical Ablation ◽

Cat Superior Colliculus ◽

Multisensory Processes ◽

Normal Adults

The ability of cat superior colliculus (SC) neurons to synthesize information from different senses depends on influences from two areas of the cortex: the anterior ectosylvian sulcus (AES) and the rostral lateral suprasylvian sulcus (rLS). Reversibly deactivating the inputs to the SC from either of these areas in normal adults severely compromises this ability and the SC-mediated behaviors that depend on it. In this study, we found that removal of these areas in neonatal animals precluded the normal development of multisensory SC processes. At maturity there was a substantial decrease in the incidence of multisensory neurons, and those multisensory neurons that did develop were highly abnormal. Their cross-modal receptive field register was severely compromised, as was their ability to integrate cross-modal stimuli. Apparently, despite the impressive plasticity of the neonatal brain, it cannot compensate for the early loss of these cortices. Surprisingly, however, neonatal removal of either AES or rLS had comparatively minor consequences on these properties. At maturity multisensory SC neurons were quite common: they developed the characteristic spatial register among their unisensory receptive fields and exhibited normal adult-like multisensory integration. These observations suggest that during early ontogeny, when the multisensory properties of SC neurons are being crafted, AES and rLS may have the ability to compensate for the loss of one another's cortico-collicular influences so that normal multisensory processes can develop in the SC.

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