scholarly journals From Fast Oscillations to Circadian Rhythms: Coupling at Multiscale Frequency Bands in the Rodent Subcortical Visual System

2021 ◽  
Vol 12 ◽  
Author(s):  
Lukasz Chrobok ◽  
Mino D. C. Belle ◽  
Jihwan Myung
Keyword(s):  
Visual System ◽  
Ganglion Cells ◽  
Brain Structures ◽  
Gamma Oscillations ◽  
Retinal Ganglion ◽  
Ambient Light ◽  
Frequency Bands ◽  
Functional Organisation ◽  
Fast Oscillations ◽  
Interesting System

The subcortical visual system (SVS) is a unique collection of brain structures localised in the thalamus, hypothalamus and midbrain. The SVS receives ambient light inputs from retinal ganglion cells and integrates this signal with internal homeostatic demands to influence physiology. During this processing, a multitude of oscillatory frequency bands coalesces, with some originating from the retinas, while others are intrinsically generated in the SVS. Collectively, these rhythms are further modulated by the day and night cycle. The multiplexing of these diverse frequency bands (from circadian to infra-slow and gamma oscillations) makes the SVS an interesting system to study coupling at multiscale frequencies. We review the functional organisation of the SVS, and the various frequencies generated and processed by its neurons. We propose a perspective on how these different frequency bands couple with one another to synchronise the activity of the SVS to control physiology and behaviour.

Expression of the BDNF gene in the developing visual system of the chick

Development ◽  
1994 ◽  
Vol 120 (6) ◽  
pp. 1643-1649 ◽  
Author(s):  
K.H. Herzog ◽  
K. Bailey ◽  
Y.A. Barde
Keyword(s):  
Visual System ◽  
Ganglion Cells ◽  
Mrna Levels ◽  
Retinal Ganglion ◽  
Bdnf Gene ◽  
Bdnf Mrna ◽  
Optic Stalk ◽  
Copy Numbers ◽  
Activity Dependent

Using a sensitive and quantitative method, the mRNA levels of brain-derived neurotrophic factor (BDNF) were determined during the development of the chick visual system. Low copy numbers were detected, and BDNF was found to be expressed in the optic tectum already 2 days before the arrival of the first retinal ganglion cell axons, suggesting an early role of BDNF in tectal development. After the beginning of tectal innervation, BDNF mRNA levels markedly increased, and optic stalk transection at day 4 (which prevents subsequent tectal innervation) was found to reduce the contralateral tectal levels of BDNF mRNA. Comparable reductions were obtained after injection of tetrodotoxin into one eye, indicating that, already during the earliest stages of target encounter in the CNS, the degree of BDNF gene expression is influenced by activity-dependent mechanisms. BDNF mRNA was also detected in the retina itself and at levels comparable to those found in the tectum. Together with previous findings indicating that BDNF prevents the death of cultured chick retinal ganglion cells, these results support the idea that the tightly controlled expression of the BDNF gene might be important in the co-ordinated development of the visual system.

scholarly journals Photoreceptive retinal ganglion cells control the information rate of the optic nerve

2018 ◽  
Vol 115 (50) ◽  
pp. E11817-E11826 ◽  
Author(s):  
Nina Milosavljevic ◽  
Riccardo Storchi ◽  
Cyril G. Eleftheriou ◽  
Andrea Colins ◽  
Rasmus S. Petersen ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Retinal Ganglion Cells ◽  
Information Flow ◽  
Information Transfer ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Ambient Light ◽  
Visual Responses ◽  
Light Irradiance ◽  
The Brain

Information transfer in the brain relies upon energetically expensive spiking activity of neurons. Rates of information flow should therefore be carefully optimized, but mechanisms to control this parameter are poorly understood. We address this deficit in the visual system, where ambient light (irradiance) is predictive of the amount of information reaching the eye and ask whether a neural measure of irradiance can therefore be used to proactively control information flow along the optic nerve. We first show that firing rates for the retina’s output neurons [retinal ganglion cells (RGCs)] scale with irradiance and are positively correlated with rates of information and the gain of visual responses. Irradiance modulates firing in the absence of any other visual signal confirming that this is a genuine response to changing ambient light. Irradiance-driven changes in firing are observed across the population of RGCs (including in both ON and OFF units) but are disrupted in mice lacking melanopsin [the photopigment of irradiance-coding intrinsically photosensitive RGCs (ipRGCs)] and can be induced under steady light exposure by chemogenetic activation of ipRGCs. Artificially elevating firing by chemogenetic excitation of ipRGCs is sufficient to increase information flow by increasing the gain of visual responses, indicating that enhanced firing is a cause of increased information transfer at higher irradiance. Our results establish a retinal circuitry driving changes in RGC firing as an active response to alterations in ambient light to adjust the amount of visual information transmitted to the brain.

scholarly journals Speed-Selectivity in Retinal Ganglion Cells is Modulated by the Complexity of the Visual Stimulus

2018 ◽  
Author(s):  
César R Ravello ◽  
Laurent U Perrinet ◽  
María-José Escobar ◽  
Adrián G Palacios
Keyword(s):  
Visual System ◽  
Retinal Ganglion Cells ◽  
Visual Stimulus ◽  
Motion Detection ◽  
Ganglion Cells ◽  
Large Body ◽  
Natural Images ◽  
Retinal Ganglion ◽  
Complex Stimuli ◽  
Different Populations

ABSTRACTMotion detection represents one of the critical tasks of the visual system and has motivated a large body of research. However, is remain unclear precisely why the response of retinal ganglion cells (RGCs) to simple artificial stimuli does not predict their response to complex naturalistic stimuli. To explore this topic, we use Motion Clouds (MC), which are synthetic textures that preserve properties of natural images and are merely parameterized, in particular by modulating the spatiotemporal spectrum complexity of the stimulus by adjusting the frequency bandwidths. By stimulating the retina of the diurnal rodent,Octodon deguswith MC we show that the RGCs respond to increasingly complex stimuli by narrowing their adjustment curves in response to movement. At the level of the population, complex stimuli produce a sparser code while preserving movement information; therefore, the stimuli are encoded more efficiently. Interestingly, these properties were observed throughout different populations of RGCs. Thus, our results reveal that the response at the level of RGCs is modulated by the naturalness of the stimulus - in particular for motion - which suggests that the tuning to the statistics of natural images already emerges at the level of the retina.

scholarly journals Infra-slow modulation of fast beta/gamma oscillations in the mouse visual system

2020 ◽  
Author(s):  
Patrycja Orlowska-Feuer ◽  
Annette Elisabeth Allen ◽  
Timothy Matthew Brown ◽  
Hanna Jowita Szkudlarek ◽  
Robert James Lucas ◽  
...  
Keyword(s):  
Visual System ◽  
Spontaneous Activity ◽  
Visual Processing ◽  
Oscillation Amplitude ◽  
Gamma Oscillations ◽  
List Type ◽  
Slow Oscillations ◽  
Genetic Ablation ◽  
Neurophysiological Activity ◽  
Fast Oscillations

ABSTRACTInfra-slow (<0.02 Hz) and fast beta/gamma (20 – 100 Hz) oscillations in neurophysiological activity have been widely found in the subcortical visual system. While it is well established that fast beta/gamma oscillations are involved in visual processing, the role (if any) of infra-slow oscillations is currently unknown. One possibility is that infra-slow oscillations exert influence by modulating the amplitude of fast oscillations, yet the extent to which these different oscillations arise independently and interact remains unknown. We addressed these questions by recording in vivo spontaneous activity from subcortical visual system of visually intact mice, and animals whose retinal network was disrupted by advanced rod/cone degeneration (rd/rd cl) or melanopsin loss (Opn4-/- We found many neurons expressing only one type of oscillation, and indeed fast oscillations were absent in rd/rd cl. Conversely, neurons co-expressing the two oscillations were also common, and were encountered more often than expected by chance in visually intact but not Opn4-/- mice. Finally, where they co-occurred we found that beta/gamma amplitude was modulated by the infra-slow rhythm. Our data thus reveal that: 1.) infra-slow and beta-gamma oscillations are separable phenomena; and 2.) that they actively co-occur in a subset of neurones in which the phase of infra-slow oscillations define beta-gamma oscillation amplitude. These findings suggest that infra-slow oscillations could influence vision by modulating beta-gamma oscillations, and raise the possibility that disruptions in these oscillatory behaviours contribute to vision dysfunction in retinal dystrophy.KEY POINTS SUMMARYNeurophysiological activity in the subcortical visual system fluctuates in both infra-slow and fast oscillatory ranges, however the level of co-occurrence and potential functional interaction of these rhythms is unknown.Analyzing dark-adapted spontaneous activity in the mouse subcortical visual system, we find that these two types of oscillation interact uniquely through a population of neurons expressing both rhythms.Genetic ablation of rod/cone signaling potentiates infra-slow and abolishes fast beta/gamma oscillations while genetic ablation of melanopsin substantially diminishes the interaction between these two rhythms.Our results indicate that in an intact visual system the phase of infra-slow modulates fast beta/gamma oscillations.Thus one possible impact of infra-slow oscillations in vision is to guide visual processing by interacting with fast narrowband oscillations.

Synchronous Period-Doubling in Flicker Vision of Salamander and Man

1998 ◽  
Vol 79 (4) ◽  
pp. 1869-1878 ◽  
Author(s):  
Daniel W. Crevier ◽  
Markus Meister
Keyword(s):  
Visual System ◽  
Ganglion Cells ◽  
Period Doubling ◽  
Bipolar Cells ◽  
Retinal Ganglion ◽  
Nonlinear Feedback ◽  
Full Field ◽  
Temporal Properties ◽  
Critical Feedback ◽  
The Brain

Crevier, Daniel W. and Markus Meister. Synchronous period-doubling in flicker vision of salamander and man. J. Neurophysiol. 79: 1869–1878, 1998. Periodic flashes of light have long served to probe the temporal properties of the visual system. Here we show that during rapid flicker of high contrast and intensity the eye reports to the brain only every other flash of light. In this regime, retinal ganglion cells of the salamander fire spikes on alternating flashes. Neurons across the entire retina are locked to the same flashes. The effect depends sharply on contrast and flash frequency. It results from a period-doubling bifurcation in retinal processing, and a simple model of nonlinear feedback reproduces the phenomenon. Pharmacological studies indicate that the critical feedback interactions require only cone photoreceptors and bipolar cells. Analogous period-doubling is observed in the human visual system. Under bright full-field flicker, the electroretinogram (ERG) shows a regime of period-doubling between 30 and 70 Hz. In visual evoked potentials from the occiput, the subharmonic component is even stronger. By analyzing the accompanying perceptual effects, we find that retinal period-doubling begins in the periphery of the visual field, and that it is the cause of a long mysterious illusory flicker pattern.

scholarly journals Cytidine 5′-Diphosphocholine (Citicoline): Evidence for a Neuroprotective Role in Glaucoma

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 793 ◽  
Author(s):  
Stefano Gandolfi ◽  
Giorgio Marchini ◽  
Aldo Caporossi ◽  
Gianluca Scuderi ◽  
Livia Tomasso ◽  
...  
Keyword(s):  
Visual Field ◽  
Therapeutic Agent ◽  
Primary Open Angle Glaucoma ◽  
Ganglion Cells ◽  
Open Angle Glaucoma ◽  
Brain Structures ◽  
Current Evidence ◽  
Retinal Ganglion ◽  
Naturally Occurring ◽  
Endogenous Compound

Glaucoma, a heterogeneous set of progressively degenerative optic neuropathies characterized by a loss of retinal ganglion cells (RGCs) and typical visual field deficits that can progress to blindness, is a neurodegenerative disease involving both ocular and visual brain structures. Although elevated intraocular pressure (IOP) remains the most important modifiable risk factor of primary open-angle glaucoma (POAG) and is the main therapeutic target in treating glaucoma, other factors that influence the disease course are involved and reaching the optimal IOP target does not stop the progression of glaucoma, as the visual field continues to narrow. In addition to a managed IOP, neuroprotection may be beneficial by slowing the progression of glaucoma and improving the visual defects. Citicoline (cytidine 5′-diphosphocholine) is a naturally occurring endogenous compound that has been investigated as a novel therapeutic agent for the management of glaucoma. Citicoline has demonstrated activity in a range of central neurodegenerative diseases, and experimental evidence suggests a it performs a neuromodulator and neuroprotective role on neuronal cells, including RGCs, associated with improvement in visual function, extension of the visual field and central benefits for the patient. This review aims to critically summarize the current evidence for the neuroprotective properties of citicoline in glaucoma.

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