Biology subjects

Shein-Idelson, M.

Publications and source records attributed to Shein-Idelson, M..

6 recordsLinked to original sources

bioRxiv2026

A personalized eye-tracking system reveals complex state-dependent visual acquisition in lizards

Gaze shifts are fundamental to visual exploration and processing, yet empirical knowledge is largely confined to a small number of model species, limiting our understanding of general principles of visual acquisition across animals. Here, we introduce a versatile, low-cost and open-source framework design for eye tracking in small freely-moving animals. Leveraging photogrammetry, 3D modeling, and 3D-printing, we produce headmounts adaptable to diverse head-eye geometries as we demonstrate for lizards, turtles, and mice. Detailed recordings in Pogona vitticeps, a laterally eyed ectotherm with a high-acuity retina, reveal a rich oculomotor repertoire with kinematics closely resembling the saccadic main sequence in primates. We found both movement-coupled large binocular saccades which exhibited a strong axial bias as well as small, isotropic, and monocular saccades suggesting a capacity for visual exploration of local details. Visual acquisition strategies were strongly tied to behavioral states with periods of active sampling (3-5Hz saccades) separated by periods of ocular stillness lasting many seconds and suggesting divergent visual acquisition strategies for ectotherms. Further, active states were correlated with pupil constriction in contrast to mammals and similarly to birds. Our results demonstrate the utility of our experimental approach for understanding visual acquisition across terrestrial vertebrates. Such a multi-perspective view on natural visual acquisition across species will be essential for developing a generalized understanding of vision, its ecological functions, and its evolutionary trajectory.

animal behavior and cognition↗

bioRxiv2024

PreyTouch: An Automated System for Prey Capture Experiments Using a Touch Screen

The ability to catch prey is crucial for survival and reproduction and is subject to strong natural selection across predators. In many animals, prey capture demands the orchestrated activation of multiple brain regions, demonstrating the intricate interplay between sensory processing, decision-making, and motor execution. This makes prey capture a prime paradigm in neuroscience. Further, its ubiquity across species makes it ideal for comparative research and for studying the evolution of cognition. However, despite recent technological advances in the collection and analysis of behavioral data, experimental approaches for studying prey catch are lagging behind. To bridge this gap, we created PreyTouch - a novel system for performing prey capture experiments on a touch screen. PreyTouch incorporates flexible presentation of prey stimulus, accurate monitoring of predator strikes and automated rewarding. The systems real time processing enables closing the loop between predator movement and prey dynamics for studying predator-prey interactions. Further, the system is optimized for automated long-term experiments and features a web-ui for remote control and monitoring. We successfully validated PreyTouch by conducting long-term prey capture experiments on the lizard Pogona Vitticeps. The acquired data revealed the existence of prey preferences, complex prey attack patterns, and fast learning of prey dynamics. The unique properties offered by PreyTouch combined with the ubiquity of prey capture behaviors across animals establish it as a valuable platform for comparatively studying animal cognition.

animal behavior and cognition↗

bioRxiv2024

Adeno-Associated Viral Tools to Trace Neural Development and Connectivity Across Amphibians

The development, evolution, and function of the vertebrate central nervous system (CNS) can be best studied using diverse model organisms. Amphibians, with their unique phylogenetic position at the transition between aquatic and terrestrial lifestyles, are valuable for understanding the origin and evolution of the tetrapod brain and spinal cord. Their metamorphic developmental transitions and unique regenerative abilities also facilitate the discovery of mechanisms for neural circuit remodeling and replacement. The genetic toolkit for amphibians, however, remains limited, with only a few species having sequenced genomes and a small number of transgenic lines available. In mammals, recombinant adeno-associated viral vectors (AAVs) have become a powerful alternative to genome modification for visualizing and perturbing the nervous system. AAVs are DNA viruses that enable neuronal transduction in both developing and adult animals with low toxicity and spatial, temporal, and cell-type specificity. However, AAVs have never been shown to transduce amphibian cells efficiently. To bridge this gap, we established a simple, scalable, and robust strategy to screen AAV serotypes in three distantly-related amphibian species: the frogs Xenopus laevis and Pelophylax bedriagae, and the salamander Pleurodeles waltl, in both developing larval tadpoles and post-metamorphic animals. For each species, we successfully identified at least two AAV serotypes capable of infecting the CNS; however, no pan-amphibian serotype was identified, indicating rapid evolution of AAV tropism. In addition, we developed an AAV-based strategy that targets isochronic cohorts of developing neurons - a critical tool for parsing neural circuit assembly. Finally, to enable visualization and manipulation of neural circuits, we identified AAV variants for retrograde tracing of neuronal projections in adult animals. Our findings expand the toolkit for amphibians to include AAVs, establish a generalizable workflow for AAV screening in non-canonical research organisms, generate testable hypotheses for the evolution of AAV tropism, and lay the foundation for modern cross-species comparisons of vertebrate CNS development, function, and evolution.

neuroscience↗

bioRxiv2023

ReptiLearn: A Smart Home Cage for Behavioral Experiments in Reptiles

Understanding behavior and its evolutionary underpinnings is crucial for unraveling the complexities of brain function. Traditional approaches strive to reduce behavioral complexity by designing short-term, highly constrained behavioral tasks with dichotomous choices in which animals respond to defined external perturbation. In contrast, natural behaviors evolve over multiple time scales and under minimally constrained conditions in which actions are selected through bi-directional interactions with the environment and without human intervention. Recent technological advancements have opened up new possibilities for more natural experimental designs by replacing stringent experimental control with accurate multidimensional behavioral analysis. However, these approaches have been tailored to fit only a small number of species. This specificity limits the experimental opportunities offered by species diversity. Further, it hampers comparative analyses which are essential for extracting overarching behavioral principles and for examining behavior from an evolutionary perspective. To address this limitation, we developed ReptiLearn - a versatile, low-cost, Python-based solution, optimized for conducting automated long-term experiments in the home cage of reptiles, without human intervention. In addition, this system offers unique features such as precise temperature measurement and control, live prey reward dispensers, engagement with touch screens, and remote control through a user-friendly web interface. Finally, ReptiLearn incorporates low-latency closed-loop feedback allowing bi-directional interactions between animals and their environments. Thus, ReptiLearn provides a comprehensive solution for researchers studying behavior in ectotherms and beyond, bridging the gap between constrained laboratory settings and natural behavior in non-conventional model systems. We demonstrate the capabilities of ReptiLearn by automatically training the lizard Pogona vitticeps on a complex spatial learning task requiring association learning, displaced reward learning and reversal learning.

animal behavior and cognition↗

bioRxiv2023

Travelling waves or sequentially activated discrete modules: mapping the granularity of cortical propagation

Numerous studies have identified travelling waves in the cortex and suggested they play important roles in brain processing. These waves are most often measured using macroscopic methods that are unable to assess the local spiking activity underlying wave dynamics. Here we investigated the possibility that waves may not be travelling at the single neuron scale. We first show that sequentially activating two discrete brain areas can appear as travelling waves in EEG simulations. We next reproduce these results using an analytical model of two sequentially activated regions. Using this model, we were able to generate wave-like activity with variable directions, velocities, and spatial patterns, and to map the discriminability limits between travelling waves and modular sequential activations. Finally, we investigated the link between field potentials and single neuron excitability using large-scale measurements from turtle cortex ex-vivo. We found that while field potentials exhibit wave-like dynamics, the underlying spiking activity was better described by consecutively activated spatially adjacent groups of neurons. Taken together, this study suggests caution when interpreting phase delay measurements as continuously propagating wavefronts in two different spatial scales. A careful distinction between modular and wave excitability profiles across scales will be critical for understanding the nature of cortical computations.

neuroscience↗

bioRxiv2020

Temporally-precise basolateral amygdala activation is required for the formation of taste memories in the gustatory cortex

Learning to associate malaise with the intake of novel food is critical for survival. Since food poisoning may take hours to affect, animals developed brain circuits to transform the current novel taste experience into a taste memory trace (TMT) and bridge this time lag. Ample studies showed that the basolateral amygdala (BLA), the nucleus basalis magnocellularis (NBM) and the gustatory cortex (GC) are involved in TMT formation and taste-malaise association. However, how dynamic activity across these brain regions during novel taste experience promotes the formation of these memories is currently unknown. We used the conditioned taste aversion (CTA) learning paradigm in combination with short-term optogenetics and electrophysiological recording in rats to test the hypothesis that temporally specific activation of BLA projection neurons is essential for TMT formation in the GC, and consequently CTA. We found that late-epoch (LE, >800ms), but not the early epoch (EE, 200-700ms), BLA activation during novel taste experience is essential for normal CTA, for early c-Fos expression in the GC (a marker of TMT formation) and for the subsequent changes in GC ensemble palatability coding. Interestingly, BLA activity was not required for intact taste identity or palatability perceptions. We further show that BLA-LE information is transmitted to GC through the BLA[->]NBM pathway where it affects the formation of taste memories. These results expose the dependence of long-term memory formation on specific temporal windows during sensory responses and the distributed circuits supporting this dependence. SignificanceConsumption of a novel taste may result in malaise and poses a threat to animals. Since the effects of poisoning appear only hours after consumption, animals must store the novel tastes information in memory until they associate it with its value (nutritious or poisonous). Here we elucidate the neuronal activity patterns and circuits that support the processing and creation of novel-taste memories in rats. Our results show that specific patterns of temporal activation in the basolateral amygdala transmitted across brain areas are important for formation of taste memory and taste-malaise association. These findings may shed light on long-term activity-to-memory transformation in other sensory modalities.

neuroscience↗