Concept

Rhodopsine

Publications associées (25)

Features integrate along a motion trajectory when object integrity is preserved

Michael Herzog, Leila Drissi Daoudi - Kleinbauer

Information about a moving object is usually poor at each retinotopic location because photoreceptor activation is short, noisy, and affected by shadows, reflections of other objects, and so on. Integration across the motion trajectory may yield a much bet ...

Association for Research in Vision and Ophthalmology (ARVO)2021

Photovoltaic stimulation of retinal microcircuit for vision restoration

Naïg Aurelia Ludmilla Chenais

Sight restoration through retinal prostheses was still a mere dream a century ago. Current challenges are even greater: providing a quantitatively and qualitatively useful artificial vision to late blind patients. Existing approaches all face engineering a ...

EPFL2021

Organic semiconductors for light-mediated neuromodulation

Diego Ghezzi, Danashi Imani Medagoda

There is growing interest in organic semiconductor devices for light-mediated neuromodulation, such as for retinal stimulation. Here, the key working principles of these devices are discussed, as well as promising applications and outstanding challenges fo ...

SPRINGERNATURE2021

The Photoisomerization Pathway(s) of Push‐Pull Phenylazoheteroarenes

Anne-Clémence Corminboeuf, Sergio Vela Llausi

Azoheteroarenes are the most recent derivatives targeted to further improve the properties of azo‐based photoswitches. Their light‐induced mechanism for trans‐cis isomerization is assumed to be very similar to that of the parent azobenzene. As such, they i ...

2020

Naturalistic spatiotemporal modulation of epiretinal stimulation increases the response persistence of retinal ganglion cell

Diego Ghezzi, Marta Jole Ildelfonsa Airaghi Leccardi, Naïg Aurelia Ludmilla Chenais

Objective. Retinal stimulation in blind patients evokes the sensation of discrete points of light called phosphenes, which allows them to perform visually guided tasks, such as orientation, navigation, object recognition, object manipulation and reading. H ...

2021

Discrete windows of feature integration

Michael Herzog, Adrien Christophe Doerig, Leila Drissi Daoudi - Kleinbauer

A car drives through the night. It is hard to estimate its color from single photoreceptor activity because photoreceptor activation is short and noisy. An efficient way to estimate the color is to average photoreceptor activities along the car’s motion tr ...

SAGE PUBLICATIONS LTD2019

A design methodology for charge-balanced stimulators based on anodic current variation monitoring

Alexandre Schmid, Reza Ranjandish

Charge balancing is a major safety concern in neural and functional electrical stimulation. This paper presents a novel and safe active charge balancing design methodology in which, after each cathodic and anodic stimulation pulse, the value of the remaini ...

2019

How Rhodopsin Tunes the Equilibrium between Protonated and Deprotonated Forms of the Retinal Chromophore

Ursula Röthlisberger, Siri Camee van Keulen, Alicia Solano

Rhodopsin is a photoactive G-protein-coupled receptor (GPCR) that converts dim light into a signal for the brain, leading to eyesight. Full activation of this GPCR is achieved after passing through several steps of the protein's photoactivation pathway. Ke ...

2017

Mechanism of ultrafast non-reactive deactivation of the retinal chromophore in non-polar solvents

Goran Zgrablic

The photoisomerization of the all-trans protonated Schiff base of retinal (SBR+) in solution is highly inefficient. The present theoretical and experimental investigation aims at disclosing the mechanisms of ultrafast, non-reactive relaxation of SBR+ that ...

Royal Soc Chemistry2017

Computational Investigation of Intracellular Signalling Cascades : from G-Protein-Coupled Receptors to Adenylyl Cyclase

Siri Camee van Keulen

In order to adjust to changes in the environment, cells can communicate via signalling cascades. A common pathway for intercellular communication is the G-protein-coupled- receptor (GPCR) signal transduction cascade which is triggered by a (chemical or phy ...

EPFL2017

Generalized QM/MM Force Matching Approach Applied to the 11-cis Protonated Schiff Base Chromophore of Rhodopsin

Ursula Röthlisberger, Ivano Tavernelli, Pablo Campomanes Ramos, Manuel Dömer

We extended a previously developed force matching approach to systems with covalent QM/MM boundaries and describe its user-friendly implementation in the publicly available software package CPMD. We applied this approach to the challenging case of the reti ...

2014

Retinal pigment epithelium protein of 65 kDA gene-linked retinal degeneration is not modulated by chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C/chondroitin sulfate proteoglycan 5

Purpose: To analyze in vivo the function of chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C (gene symbol: Cspg5) during retinal degeneration in the Rpe65(-/-) mouse model of Leber congenital amaurosis. ...

Molecular Vision2013

Depletion-interaction effects on the tunneling conductivity of nanorod suspensions

Peter Ryser, Claudio Grimaldi, Biagio Nigro

We study by simulation and theory how the addition of insulating spherical particles affects the conductivity of fluids of conducting rods, modeled by spherocylinders. The electrical connections are implemented as tunneling processes, leading to a more det ...

American Physical Society2013

Retinal and post-retinal contributions to the quantum efficiency of the human eye revealed by electrical neuroimaging

Enrico Pomarico

The retina is one of the best known quantum detectors with rods able to reliably respond to single photons. However, estimates on the number of photons eliciting conscious perception, based on signal detection theory, are systematically above these values ...

Frontiers Media2013

How are non-retinotopic motion signals integrated? -A high-density EEG study

Michael Herzog, Gijs Plomp, Yvonne Evelina Thunell

Objects moving in the visual scene cause retinal displacements that are not the result of motor commands and thus cannot be accounted for by efference copies. Yet, we easily keep track of moving objects even without following them with our gaze. Here, we i ...

2013

Early apoptosis of rod photoreceptors in Rpe65(-/-) mice is associated with the upregulated expression of lysosomal-mediated autophagic genes

RPE65-related Leber's congenital amaurosis (LCA) is a rod-cone dystrophy whose clinical outcome is mainly attributed to the loss of rod photoreceptors followed by cone degeneration. Pathogenesis in Rpe65-/- mice is characterized by a slow and progressive d ...

2012

Convenient Preparation of Tri-tert-butylphosphonium Tetrafluoroborate

Nicolai Cramer, Tanguy Jean Daniel Saget

The versatile tri-tert-butylphosphonium tetrafluoroborate ligand is prepared in a convenient, simple, and high-yielding procedure without the isolation of sensitive intermediates. ...

2011

Exploring G-Protein Coupled Receptor Activation with Multiscale Molecular Simulations

Stefano Vanni

This thesis is devoted to the study of the activation mechanism of G-protein coupled receptors (GPCRs), one of the largest and most diverse protein families in mammalian genomes, by means of different computer-based simulation techniques. Using force field ...

EPFL2011

A conserved protonation-induced switch can trigger "ionic lock" formation in adrenergic receptors

Ursula Röthlisberger, Ivano Tavernelli, Marilisa Neri, Stefano Vanni

The mechanism of signal transduction in G-protein-coupled receptors (GPCRs) is a crucial step in cell signaling. However, the molecular details of this process are still largely undetermined. Carrying out submicrosecond molecular dynamics simulations of be ...

Elsevier2010

Long-range energy transfer in proteins

Francesco Piazza

Proteins are large and complex molecular machines. In order to perform their function, most of them need energy, e. g. either in the form of a photon, as in the case of the visual pigment rhodopsin, or through the breaking of a chemical bond, as in the pre ...

2009