Morphology and connectivity of retinal horizontal cells in two avian species

Frontiers in Cellular Neuroscience, Год журнала: 2025, Номер 19

Опубликована: Март 4, 2025

In the outer vertebrate retina, visual signal is separated into intensity and wavelength information. birds, seven types of photoreceptors (one rod, four single cones, two members double cone) mediate signals to >20 second-order neurons, bipolar cells horizontal cells. Horizontal contribute color contrast processing by providing feedback feedforward fish, reptiles, amphibians they either encode or show color-opponent responses. Yet, for bird number cell not fully resolved even more importantly, synapses between have never been quantified any species. With a combination light microscopy serial EM reconstructions, we found different in distantly related species, domestic chicken European robin. agreement with some earlier studies, confirmed highly abundant (H1, H2) rare (H3, H4), which H1 an axon-bearing cell, whereas H2-H4 are axonless. made chemical one type interplexiform amacrine at their soma. Dendritic contacts H1-H4 were type-specific similar turtle confirms high degree evolutionary conservation retina. Our data further suggests that potentially H2 may intensity, H3 H4 represent opponent birds’ superb and/or acuity vision.

Язык: Английский

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Conservation of cis-regulatory codes over half a billion years of evolution

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Ноя. 14, 2024

ABSTRACT The identification of homologous cell types across species represents a crucial step in understanding type evolution. retina is particularly amenable to comparative analysis because the basic morphology, connectivity, and function its six major classes have remained largely invariant since earliest stages vertebrate Here, we show that retina’s highly conserved cellular architecture mirrored by deep conservation underlying cis -regulatory codes control gene expression. We use single-cell chromatin accessibility lamprey, fish, bird, mammalian retinas— representing over half billion years evolutionary divergence—to demonstrate cross-species all retinal classes. This persists despite extensive turnover regions between distant species. Conservation manifests as clustering multiple distinct high-affinity transcription factor (TF) binding sites toward center cell-class-specific open with little preservation higher-order syntax. Hierarchical machine-learning models from diverse recovers clusters corresponding Thus, Bauplan controlled which predate divergence extant vertebrates persist nearly complete enhancer turnover.

Язык: Английский

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Robust Sensory Traits Across Light Habitats: Visual Signals but Not Receptors Vary in Centrarchids Inhabiting Distinct Photic Environments

Molecular Ecology, Год журнала: 2025, Номер unknown

Опубликована: Март 11, 2025

ABSTRACT Visual communication in fish is often shaped by their light environment, which influences both sensory (e.g., eye size, opsin gene expression) and signalling traits body reflectance). This study explores the phenotypic variation visual of six species centrarchids (Centrarchidae) inhabiting two contrasting environments. We measured morphological, molecular to determine across photic conditions. Our findings reveal significant interspecific but no consistent between Centrarchids showed robust systems with green‐sensitive rh2 red‐sensitive lws genes representing main chromatic channels, expression remaining largely unaffected distinct habitats. also found evolution genes, although these changes were not associated environmental However, reflectance displayed species‐specific responses conditions, suggesting that may be more flexible than traits. Overall, our results challenge generality current paradigm ecology, portrays as highly tunable owing highlights potential evolutionary or developmental constraints on centrarchid implications for adaptability various habitats novel threats.

Язык: Английский

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Differential retinal ganglion cell resilience to optic nerve injury across vertebrate species

Frontiers in Neuroscience, Год журнала: 2025, Номер 19

Опубликована: Май 20, 2025

Optic neuropathies comprise a diverse group of disorders that ultimately lead to retinal ganglion cell (RGC) degeneration. Despite varying etiologies, these conditions share conserved pathological progression: axonal damage in the optic nerve triggers progressive RGC Understanding species-specific differences neuronal resilience is critical for identifying key survival mechanisms and potential neuroprotective targets. In this study, we compare densities rates following crush (ONC) three vertebrate models-mice, zebrafish, killifish-under standardized experimental conditions. Transcriptomic analysis confirmed that, similar RBPMS mice, Rbpms2 serves as pan-RGC marker zebrafish killifish. Using markers, reveal significant density, with fish species exhibiting over 5-fold higher density than mice at equivalent life stage. Killifish also show an age-dependent decline density. Furthermore, identify distinct injury responses across species: undergo rapid degeneration, losing ∼80% their RGCs by day 14 after ONC; maintain full retention 2 weeks before experiencing loss ∼12%; killifish display biphasic response ONC, young adults retaining two-thirds 21, while older exhibit more pronounced second wave loss, preserving just half 21 days injury. These findings highlight fundamental capacity among species, providing comparative framework uncover molecular governing therapeutic strategies treating neurodegeneration pathologies.

Язык: Английский

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Mosaic evolution of a learning and memory circuit in Heliconiini butterflies

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Апрель 24, 2024

Abstract A critical function of central neural circuits is to integrate sensory and internal information cause a behavioural output. Evolution modifies such generate adaptive change in detection behaviour, but it remains unclear how selection does so the context existing functional developmental constraints. Here, we explore this question by analysing evolutionary dynamics insect mushroom body circuits. Mushroom bodies are constructed from conserved wiring logic, mainly consisting Kenyon cells, dopaminergic neurons output neurons. cells carry identity signals, which modified strength carried forward into other brain areas Despite makeup circuit, there huge diversity size shape across insects. However, an empirical framework evolution architecture circuit largely lacking. To address this, leverage recent radiation Neotropical tribe butterflies, Heliconiini (Nymphalidae), show extensive variation over comparatively short phylogenetic timescales, linked specific changes foraging ecology, life history cognition. understand mechanism increase accommodated through lobe architecture, first combined immunostainings structural markers, neurotransmitters injections generate, our knowledge, most detailed description Papilionoidea butterfly lobe. We then provide comparative, quantitative dataset shows that some cell populations expanded with higher rate than others Heliconius , providing anatomical parallel shifts behaviour. Finally, identified GABA-ergic feedback essential for non-elemental learning sparse coding, conservation neuron number. Taken together, results demonstrate mosaic functionally related systems types identify malleability architecturally guides adaptation cognitive ability.

Язык: Английский

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Mosaic evolution of a learning and memory circuit in Heliconiini butterflies

Current Biology, Год журнала: 2024, Номер unknown

Опубликована: Окт. 1, 2024

Язык: Английский

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