Retinal ganglion cells

…to permeate the inner retina, causing retinal ganglion cells to become spontaneously hyperactive, severely reducing the signal-to-noise ratio, and creating interference in the communication between the surviving retina and the brain. Treatments aimed at blocking or reducing hyperactivity improve vision initiated from surviving photoreceptors and could enhance the signal fidelity genera

Retinal ganglion cells (RGCs) show high convergence onto their downstream projections, which poses a problem for information transfer: how is it possible to preserve information through a synaptic layer that has significantly more inputs than outputs? There are an infinite number of ways to perform compression, and lossy compression suggests efficient yet computation-agnostic methods for reading out input stimuli or activity patterns. However, downstream neurons must perform essential computations on their inputs for the organism’s survival, rather than simply recapitulate input activity. In t

The fact that the eyes are constantly in motion, even during ‘fixation’, implies that retinal ganglion cells' spike times carry information about the visual scene even when the scene is static. Moreover, this motion implies that fine details of the visual scene could not be decoded from pure spatial retinal representations due to smearing. Understanding the interplay of temporal and spatial information in visual processing is thus pivotal for both biological research and bio-inspired computer-vision applications. In this study, we consider data from an event-based camera that was designed to e

Information in sensory neurons is conveyed by spiking activity varying in time. This is quantified by the mutual-information rate (MIR), given by $\mathrm{MIR}:=\underset{\Delta t\rightarrow\infty}{\lim}\frac{{\cal I}\left(\Delta t\right)}{\Delta t}$, where ${\cal I}\left(\Delta t\right)$ is the mutual information between the activity of a spiking neuron and a stimulus over a given time window $\Delta t$. To compute it for spiking data, the spike train is typically discretized with a certain bin-size $\mathrm{dt}$. Because $\Delta t/\mathrm{dt}$ is typically well bigger than $1$, there are man

…recorded spiking activity from mouse retinal ganglion cells (RGCs) in

Identifying the mechanisms underlying the early stage of hypoxic injury of the retinocollicular neurotransmission will provide valuable insights that may be beneficial for the future intervening in visual attention and perception deficits and preventing their progressions. Previously, we have demonstrated that the protein kinase C (PKC) signaling pathway mediates hypoxia-induced LTP of NMDA retinocollicular neurotransmission. The potent and selective inhibitor of PKC - chelerythrine chloride (ChC, 5 µM) completely blocked the induction of LTP by hypoxia and even reversed already induced one. H

By applying electrical stimulation, retinal prostheses aim to bypass dysfunctional photoreceptors and directly activate retinal ganglion cells (RGCs). Therefore, effective modulation of RGCs is the key step in the development of retinal prostheses. Six cynomolgus monkeys were used: three as a control and the other three as an N-methyl-N-nitrosourea (MNU)-induced retinal degeneration model. The retinal recording was performed using the 8x8 multi-electrode array. Figure shows the electrical stimulation pulses (a), raster plots of RGC spikes (b), and the modulation efficiency score (MES) (c). The

…the early light experience modulate retinal waves during the first postnatal week in mice. In the experiment, we used micro-electrode array (MEA) for electrophysiological recording. The retina from postnatal 3 to 8 days of mice were isolated under the dim red light and placed on MEA chip to

Retinal ganglion cells (RGCs) transmit visual information from the retina to the brain and are conserved among vertebrates. In zebrafish, RGCs project their axons to downstream brain areas known as arborization fields (AFs). Previous anatomical studies have demonstrated that each RGC axon targets one or a few of AF1-9 and 10 distinct layers of AF10 (optic tectum). Although it was proposed that each projection type represents one functional type, the correspondence between morphology and function of genetically defined RGC subtypes is still unclear. To address this question, we focused on RGC s

Ultrasound stimulation of the retina was proposed as an alternative to retinal prostheses for visual restoration. Prior works have shown that the retina responds to mechanical stimulation, but no attempt on stimulating an ex vivo retina with a free-standing photoacoustic membrane had yet been made. Here, we report ultrahigh precision stimulation of the retina with optically generated focused ultrasound (OFUS). OFUS is generated with a photoacoustic membrane of embedded carbon nanoparticles in polydimetylsiloxane. Using ex vivo multielectrode array recording and pharmalogical approaches, we inv

Retinal ganglion cells (RGC) are the first neurons generating action potentials in the visual pathway. In order to convert presynaptic inputs from bipolar and amacrine cells into meaningful output, spike generation in RGCs must be robust in different scenarios. While spike generation is mostly influenced by biophysical properties of RGCs, here we investigated the influence of dendritic morphology on action potential dynamics, thresholds and firing rates in three types of mouse alpha RGCs.Tracings of ON-alpha sustained (ON-αs), OFF-alpha sustained (OFF-αs) and OFF-alpha transient (OFF-αt) RGCs

…Retinal ganglion cells (RGCs) are the final output neurons in the retinal pathway; their output is thought to be mainly determined by presynaptic inputs; however, recent evidence suggests that the biophysical properties of RGCs such as the axon initial segment (AIS) also play an important part in signal modulation.Whole-cell patch-clamp experiments were performed to measure the spiking responses of ON-alpha sustained (ON-αs), OFF-alpha sustained (OFF-αs), and OFF-alpha transient (OFF-αt)

Binocular viewing improves several aspects of visual detection compared to viewing with one eye alone, in a process known as binocular summation. A striking example of this perceptual binocular enhancement is how binocular viewing enables the detection of lower contrasts compared to monocular viewing. However, the neuronal substrate of such improved binocular contrast detection in the visual system has so far been poorly understood. The majority of binocular interactions are thought to occur in binocular neurons of the visual cortex. Earlier parts of the image-forming visual pathway have been

…in vivo 2-photons calcium imaging in retinal ganglion cells (RG

…proposed as a niche of neural stem cells because, in vitro, cells from this area are able to form neurospheres, proliferate and differentiate. Here, we explore the potential of CB cells to differentiate and replace degenerated retinal ganglion cells (RGCs) in vivo. CB cells isolated from adult retinas and intravitreally injected into the retina of mice that had been previously depleted of RGCs by optic nerve axotomy, integrate into the ganglion cell layer and express neuronal markers. A different type of

We have recently identified Tusc5 as a Retinal Ganglion Cell (RGC) marker, specifically expressed in Brn3a+ RGCs, and absent from Brn3aKO retinas. Tusc5 is a transmembrane protein that assists trafficking of Glucose transporter GluT4 in adipocites. GluT4 are continuously recycled through endosomes from and to the plasma membrane and stored in GSVs (Glut4 Storage Vesicles), in an insulin-dependent manner. In adipocites, GluT4 recycling is assisted by Tusc5. In mouse retina, Tusc5 is expressed specifically in a subset of Brn3a+ retinal ganglion cells (RGCs), characterized by small dense “bushy”

Our aim was to investigate the distribution of retinal ganglion cells and visual acuity in hedgehogs, nocturnal insectivores with reputedly poor vision. Adult Erinaceus europaeus and E. roumanicus, two hedgehog species found in Austria, were studied. The eyes were enucleated, fixed, and ocular anatomical parameters were measured. To identify retinal ganglion cells (RGCs), Brn3a, which is expressed by vision-forming RGCs, and RBPMS, which is expressed by vision- and non-vision-forming RGCs, were visualized by fluorescence immunolabeling of retinal frozen sections and wholemounts. RGC density wa

Axonal protein synthesis seems to play an important role in retinal ganglion cells (RGCs) axon guidance because axonal mRNAs could be locally translated “on demand” during axonal navigation. During embryonic development, RGC axons project to the brain and have to decide whether or not to cross the midline at the level of the optic chiasm. There are two types of RGCs, the contralateral ones (cRGCs) that respond to attractive cues; and the ipsilateral ones (iRGCs), that respond to repulsive cues. Although RGCs growth cones have a very fast dynamic behavior in response to environmental stimuli, k

Electrical-based neuroprostheses reported promising clinical outcomes for the treatment of neurological disorders. Nevertheless, they suffer from low spatial resolution and lack of natural neurotransmission specificity that require alternative bio-mimetic stimulation strategies. Chemical-based neuroprostheses would represent a promising option to emulate the physiological synaptic communication by providing localized delivery of neurotransmitters. While various drug delivery approaches have been investigated, an efficient neurotransmitter-based neuronal stimulation at the nanoscale still remai

…a defined neuronal circuit to retinal ganglion cells, which project to the visual centers of the brain. Microglia have been shown to fine-tune the neuronal circuitry by pruning functionally weak synapses during brain development. However, we do not know whether microglia have a similar impact on the neuronal circuit of the retina.In mice, microglia invade the developing retina as early as embryonic age (E) 11.5, where they reside in in the emerging outer- (OPL) and inner plexiform layer (IPL) throughout adulthood. Here, we investigat

Diabetic retinopathy (DR), a common complication of diabetes, is a leading cause of blindness among working-age individuals worldwide. Traditionally, DR was considered primarily a microvascular complication, categorized as either nonproliferative or proliferative based on neovascularization presence. However, emerging evidence suggested that neurodegeneration plays a crucial role in DR beyond its microvascular aspects. Neurotrophic factors, such as nerve growth factor (NGF), have significant effects on neuronal survival. In the visual system, NGF influences retina and optic nerve development,

Neurons are equipped with powerful analog processing units – dendrites. However, the role linear and nonlinear dendritic properties play in shaping a neuron’s output to filter behaviorally relevant information and subsequently drive behavior, is poorly understood. Here, we address this question using wide-field neurons of the mouse superior colliculus; a genetically targetable midbrain cell-type that receives direct input from the retina and mediates innate defensive and hunting behaviors. To understand how wide-field neurons combine their inputs, we measured their output: the responses to beh

…This work focuses on using the retinal encoding of natural movies to determine the presumably behaviorally-relevant features that the brain represents. It is prohibitive to parameterize a natural movie and its respective retinal encoding fully. We use time within a natural movie as a proxy for the whol

…neuroengineering applications such as retinal prostheses. Although the processing of visual information in the healthy retina has been studied in detail, no comprehensive computational model exists that captures the many cell-level and network-level biophysical changes common to retinal degenerative diseases. To address this challenge, we developed a biophysically detailed model of the retinal circuitry and simulated the network-level response to both light and electrical stimulation. The model included 11,138 c