Biology subjects

Roska, B.

Publications and source records attributed to Roska, B..

14 recordsLinked to original sources

bioRxiv2026

Modular chronic cranial platform for longitudinal functional ultrasound, optical, and ECoG recording in a gyrencephalic model species

Understanding cortical function in large, gyrencephalic brains requires following the same tissue over time and interrogating it through complementary methods - yet in practice each recording modality is run on its own preparation, across separate animals and sessions that cannot be quantitatively related, while the recorded cortex can rarely be revisited. Functional ultrasound (fUS), widefield optical imaging, and electrocorticography (ECoG) are individually mature and strongly complementary, but no single preparation has combined all three within the same chronically accessible tissue in a gyrencephalic brain. Here we present a modular chronic cranial platform, validated in three cats with implants remaining functional for up to 3.3 years that unites these modalities in one customized chamber built around fUS as an anchor modality. The platform also supports fUS imaging in awake, head-unrestrained animals, with activation maps remaining spatially consistent across imaging days. By providing stable, quantitatively reproducible access to the same cortical region over time, this platform enables longitudinal, multimodal characterization of cortical function within individual subjects.

neuroscience↗

bioRxiv2025

In vivo single-cell gene editing using RNA electroporation reveals sequential adaptation of cortical neurons to excitatory-inhibitory imbalance

The balance between excitatory and inhibitory neurotransmission is fundamental for normal brain function, yet the adaptation of individual neurons to disrupted excitatory-inhibitory balance is not well understood. We developed highly efficient, in vivo RNA electroporation-based single-cell gene editing to investigate neuronal responses to loss of fast inhibition. Using CRISPR-Cas9 components delivered as RNA, we knocked out GABA-A receptor {beta} subunits in individual layer 2/3 cortical neurons in mouse visual cortex, eliminating fast inhibition. In vivo patch-clamp recordings revealed that cortical neurons adapted to inhibition loss through two sequential mechanisms: a transient reduction of excitatory synaptic input, followed by intrinsic membrane property changes that decreased input resistance. This sequential adaptation program ultimately prevented target neurons from contributing spikes to the cortical network. Our RNA-based single-cell gene editing approach enables investigation of cellular responses independent of network effects, providing new insights into neuronal homeostasis and gene function in individual cells in vivo.

neuroscience↗

bioRxiv2025

Joint visual-vestibular computation of head direction and reflexive eye movement

Several cognitive maps have been identified, but what sensory signals drive them and how these are combined are not well understood. One such map, the head-direction representation, is believed to be primarily driven by vestibular motion signals in mammals. Here, we combine in vivo imaging of neuronal activity, genetic perturbation of neuronal circuits, behavioral testing, and theoretical modeling to show that the representation of head direction in mouse is driven by not only vestibular but also visual motion signals: both are essential, and the latter, originating in direction-selective retinal ganglion cell activity, dominates at low speeds. We show that, correspondingly, visual perturbations alter navigational behavior that relies on head-direction computation. Finally, we find that head-direction representation and the slow phase of reflexive eye movement are tightly correlated, and we propose a theoretical model that elucidates their emergence from coupled visual and vestibular processes. Our results suggest that the brains estimate of head direction is built on an oculomotor reflex pathway driven by both visual and vestibular signals.

neuroscience↗

bioRxiv2025

Engineering Infrared Light Detection in Blind Human Retina Using Ultrasensitive Human TRPV1 Channels

Engineering infrared light sensitivity in the blind human retina could restore visual function in patients with regional retinal degeneration. However, current approaches are complex and contain non-human biological components. Using rational protein design we engineered human TRPV1 channels ({Delta}786-840) with temperature sensitivity shifted from 45 to 41{degrees}C that enabled near-infrared light- induced heat activation of mammalian cells at close to physiological temperatures. When expressed in ganglion cells of human retinal explants, {Delta}786-840 TRPV1 generated robust spiking responses to brief near-infrared light-induced temperature transients. Additionally, increasing intensity of radiation evoked graded responses correlating with increasing firing frequencies. Unlike previous approaches that used non-human TRPV1 channels, which risk immune reactions and a multicomponent system that poses barriers to clinical implementation, this single component human-derived approach eliminates immunogenicity concerns, addressing a major challenge to clinical translation, and allow gene delivery using adeno-associated viral vectors.

bioengineering↗

bioRxiv2024

An implantable biohybrid nerve model towards synaptic deep brain stimulation

Restoring functional vision in blind patients lacking a healthy optic nerve requires bypassing retinal circuits, ideally, by directly stimulating the visual thalamus. However, available deep brain stimulation electrodes do not provide the resolution required for vision restoration. We developed an implantable biohybrid nerve model designed for synaptic stimulation of deep brain targets. The interface combines a stretchable stimulation array with an aligned microfluidic axon guidance system seeded with neural spheroids to facilitate the development of a 3 mm long nerve-like structure. A bioresorbable hydrogel nerve conduit was used as a bridge between the tissue and the biohybrid implant. We demonstrated stimulation of spheroids within the biohybrid structure in vitro and used high-density CMOS microelectrode arrays to show faithful activity conduction across the device. Finally, implantation of the biohybrid nerve onto the mouse cortex showed that neural spheroids grow axons in vivo and remain functionally active for more than 22 days post-implantation.

bioengineering↗

bioRxiv2024

Action potential propagation speed compensates for traveling distance in the human retina

Neural information processing requires accurately timed action potentials arriving from presynaptic neurons at the postsynaptic neuron. However, axons of ganglion cells in the human retina feature low axonal conduction speeds and vastly different lengths, which poses a challenge to the brain for constructing a temporally coherent image over the visual field. Combining results from microelectrode array recordings, human behavioral measurements, transmission electron microscopy, and mathematical modelling of the retinal nerve fiber layer, we demonstrate that axonal propagation speeds compensate for variations in axonal length across the human retina including the fovea. The human brain synchronizes the arrival times of action potentials at the optic disc by increasing the diameters of longer axons, which increases their propagation speeds.

neuroscience↗

bioRxiv2023

Cell type-focused compound screen in human organoids reveals molecules and pathways controlling cone photoreceptor death

Human organoids that mirror their corresponding organs in cell-type diversity present an opportunity to perform large-scale screens for compounds that protect disease-affected or damage healthy cell types. However, such screens have not yet been performed. Here, we generated 20,000 human retinal organoids with GFP-labeled cone photoreceptors. Since degeneration of cones is a leading cause of blindness, we induced cone death and screened 2,707 compounds with known targets, for those that saved cones or those that further damaged cones. We identified inhibitors of CK1 or MAPK11 that protected cones, HSP90 inhibitors that saved cones in the short term but damaged them in the longer term, and broad HDAC inhibition by many compounds that significantly damaged cones. This work provides a database for cone-damaging compounds and describes compounds that can be starting points to develop neuroprotection for cones in diseases such as macular degeneration.

neuroscience↗

bioRxiv2023

High-efficiency base editing for Stargardt disease in mice, non-human primates, and human retina tissue

Stargardt disease is a currently untreatable, inherited neurodegenerative disease that leads to macular degeneration and blindness due to loss-of-function mutations in the ABCA4 gene. We have designed a dual adeno-associated viral vector split-intein adenine base-editing strategy to correct the most common mutation in ABCA4 (c.5882G>A, p.G1961E). We optimized ABCA4 base editing in human models, including retinal organoids, iPSC-derived retinal pigment epithelial (RPE) cells, as well as adult human retinal- and RPE/choroid explants in vitro. The resulting gene therapy vectors achieved high levels of gene correction in mutation-carrying mice and in non-human primates, with an average editing of 37% of photoreceptors and 73% of RPE cells in vivo. The high editing rates in primates make way for precise and efficient gene editing in other neurodegenerative ocular diseases.

neuroscience↗

bioRxiv2023

Individual thalamic inhibitory interneurons are functionally specialized towards distinct visual features

Inhibitory interneurons in the dorsolateral geniculate nucleus (dLGN) are situated at the first central synapse of the image-forming visual pathway but little is known about their function. Given their anatomy, they are expected to be multiplexors, integrating many different retinal channels along their dendrites. Here, using targeted single-cell-initiated rabies tracing, we found that mouse dLGN interneurons exhibit a degree of retinal input specialization similar to thalamocortical neurons. Some are anatomically highly specialized, for example, towards direction-selective information. Two-photon calcium imaging performed in vivo revealed that interneurons are also functionally specialized. In mice lacking retinal horizontal direction selectivity, horizontal direction selectivity is reduced in interneurons, suggesting a causal link between input and functional specialization. Functional specialization is not only present at interneuron somata, but also extends into their dendrites. Altogether, each inhibitory interneuron globally encodes one visual feature originating mostly in the retina and is ideally suited to perform feature-selective inhibition.

neuroscience↗

bioRxiv2022

Embryonic cortical layer 5 pyramidal neurons form an active, transient circuit motif perturbed by autism-associated mutations

Cortical circuits are composed predominantly of pyramidal-to-pyramidal neuron connections, yet their assembly during embryonic development is not well understood. We show that embryonic layer 5 pyramidal neurons, identified through single cell transcriptomics, display two phases of circuit assembly in vivo. At E14.5, a multi-layered circuit motif, composed of a single layer 5 cell type, forms. This motif is transient, switching to a second circuit motif, involving all three types, by E17.5. In vivo targeted single cell recordings and two-photon calcium imaging of embryonic layer 5 neurons reveal that, in both phases, neurons have active somas and neurites, tetrodotoxin-sensitive voltage-gated conductances, and functional glutamatergic synapses. Embryonic layer 5 neurons strongly express autism-associated genes, and perturbing these genes disrupts the switch between the two motifs. Hence, layer 5 pyramidal neurons form transient active pyramidal-to-pyramidal circuits, at the inception of neocortex, and studying these circuits could yield insights into the etiology of autism.

neuroscience↗

bioRxiv2021

Sonogenetic stimulation of the brain at a spatiotemporal resolution suitable for vision restoration

Remote, precisely controlled activation of the brain is a fundamental challenge in the development of brain-machine interfaces providing feasible rehabilitation strategies for neurological disorders. Low-frequency ultrasound stimulation can be used to modulate neuronal activity deep in the brain1-7, but this approach lacks spatial resolution and cellular selectivity and loads the brain with high levels of acoustic energy. The combination of the expression of ultrasound-sensitive proteins with ultrasound stimulation ( sonogenetic stimulation) can provide cellular selectivity and higher sensitivity, but such strategies have been subject to severe limitations in terms of spatiotemporal resolution in vivo8-10, precluding their use for real-life applications. We used the expression of large-conductance mechanosensitive ion channels (MscL) with high-frequency ultrasonic stimulation for a duration of milliseconds to activate neurons selectively at a relatively high spatiotemporal resolution in the rat retina ex vivo and the primary visual cortex of rodents in vivo. This spatiotemporal resolution was achieved at low energy levels associated with negligible tissue heating and far below those leading to complications in ultrasound neuromodulation6,11. We showed, in an associative learning test, that sonogenetic stimulation of the visual cortex generated light perception. Our findings demonstrate that sonogenetic stimulation is compatible with millisecond pattern presentation for visual restoration at the cortical level. They represent a step towards the precise transfer of information over large distances to the cortical and subcortical regions of the brain via an approach less invasive than that associated with current brain-machine interfaces and with a wide range of applications in neurological disorders.

neuroscience↗

bioRxiv2019

Cell types of the human retina and its organoids at single-cell resolution: developmental convergence, transcriptomic identity, and disease map

How closely human organoids recapitulate cell-type diversity and cell-type maturation of their target organs is not well understood. We developed human retinal organoids with multiple nuclear and synaptic layers. We sequenced the RNA of 158,844 single cells from these organoids at six developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable developed state at a rate similar to human retina development in vivo and the transcriptomes of organoid cell types converged towards the transcriptomes of adult peripheral retinal cell types. The expression of disease-associated genes was significantly cell-type specific in adult retina and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in adult human retinas.

neuroscience↗

bioRxiv2019

The mesoSPIM initiative: open-source light-sheet mesoscopes for imaging in cleared tissue

Over the course of the past decade, tissue clearing methods have reached a high level of sophistication with a wide variety of approaches now available1. To image large cleared samples, light-sheet microscopes have proven to be ideal due to their excellent optical sectioning capability in transparent tissue2. Such instruments have recently seen extensive technological and commercial development. However, despite this progress, the community is lacking instruments capable of exploring large samples with near-isotropic resolution within minutes. Here, we introduce the mesoscale selective plane-illumination microscopy (mesoSPIM) initiative, an open-hardware project that provides researchers with instructions and software to easily build and operate light-sheet microscopes for centimeter-sized cleared samples (http://www.mesospim.org).\n\nA wide range of commercial light-sheet microscopes have ...

neuroscience↗

bioRxiv2018

Targeting neuronal and glial cell types with synthetic promoter AAVs in mice, non-human primates, and humans

Targeting genes to specific neuronal or glial cell types is valuable both for understanding and for repairing brain circuits. Adeno-associated viral vectors (AAVs) are frequently used for gene delivery, but targeting expression to specific cell types is a challenge. We created a library of 230 AAVs, each with a different synthetic promoter designed using four independent strategies. We show that ~11% of these AAVs specifically target expression to neuronal and glial cell types in the mouse retina, mouse brain, non-human primate retina in vivo, and in the human retina in vitro. We demonstrate applications for recording, stimulation, and molecular characterization, as well as the intersectional and combinatorial labeling of cell types. These resources and approaches allow economic, fast, and efficient cell-type targeting in a variety of species, both for fundamental science and for gene therapy.

neuroscience↗