Temporal Profile of Brain Gene Expression After Prey Catching Conditioning in an Anuran Amphibian

PreyTouch: a touchscreen-based closed-loop system for studying predator-prey interactions

The ability to catch prey is crucial for survival and reproduction and is subject to strong natural selection across predators. Prey capture demands the orchestrated activation of multiple brain regions and the interplay between sensory processing, decision-making, and motor execution. These factors, together with the ubiquity of prey capture across species makes it appealing for comparative studies across neuroscience and ecology. However, despite recent technological advances, experimental approaches for studying natural behaviors such as prey catch are lagging behind. To bridge this gap, we created PreyTouch-a novel approach for performing prey capture experiments that incorporate flexible prey control, accurate monitoring of predator touchscreen strikes and automated rewarding. Further, its real-time processing enables coupling predator movement and prey dynamics for studying predator-prey interactions. Finally, PreyTouch is optimized for automated long-term experiments featuring a web UI for remote control and monitoring. We successfully validated PreyTouch by conducting long-term prey capture experiments on the lizard Pogona vitticeps. This revealed the existence of prey preferences, complex prey attack patterns, and fast learning of prey dynamics. PreyTouch's unique features and the importance of studying prey capture behavior make it a valuable platform for connecting natural behavior with cognitive studies across various species and disciplines.

Transcriptomic signature of extinction learning in the brain of the fire-bellied toad, Bombina orientalis

Insight into the molecular and cellular mechanisms of learning and memory from a diverse array of taxa contributes to our understanding of the evolution of these processes. The fire-bellied toad, Bombina orientalis, is a basal anuran amphibian model species who could help us describe shared and divergent characteristics of learning and memory mechanisms between amphibians and other vertebrates, and hence answer questions about the evolution of learning. Utilizing next generation sequencing techniques, we profiled gene expression patterns associated with the extinction of prey-catching conditioning in the brain of the fire-bellied toad. For this purpose, gene expression was at first compared between toads sacrificed after acquisition and extinction of the conditioned response. A second comparison was done between toads submitted to extinction following either short or long acquisition training, which results in toads displaying response extinction or resistance to extinction, respectively. We analyzed brain tissue transcription profiles common to both acquisition and extinction learning, or unique to extinction learning and resistance to extinction, and found significant overlap in gene expression related to molecular pathways involving neuronal plasticity (e.g. structural modification, transcription). However, extinction learning induced a unique GABAergic transcriptomic signal, which may be responsible for suppression of the original response memory. Further, when comparing extinction learning in short- and long-trained groups, short training engaged many pathways related to neuronal plasticity, as expected, but long training engaged molecular pathways related to the suppression of learning through epigenetic mediated transcriptional suppression and inhibitory neurotransmission. Overall, gene expression patterns associated with extinction learning in the fire-bellied toad were similar to those found in mammals submitted to extinction, although some divergent profiles highlighted potential differences in the mechanisms of learning and memory among tetrapods.