Biology subjects

Ravens, A.

Publications and source records attributed to Ravens, A..

2 recordsLinked to original sources

bioRxiv2024

Arc mediates intercellular synaptic plasticity via IRSp53-dependent extracellular vesicle biogenesis.

Current models of learning and memory have focused on cell-autonomous regulation of synaptic strength; however, intercellular signaling between cells in the brain is important for normal cognition. The immediate early gene Arc is a repurposed retrotransposon critical for long-term forms of synaptic plasticity and memory. Arc protein forms virus-like capsids released in extracellular vesicles (EVs) that mediate intercellular signaling of unknown function. Here, we find that long-term potentiation stimuli induce the biogenesis of Arc EVs by recruiting the I-BAR protein IRSp53, which facilitates Arc capsid assembly, trafficking, and release from actin-rich filopodial structures in dendrites. Arc EVs transfer Arc protein and mRNA to neighboring dendrites, where translation of transferred Arc mRNA induces a loss of surface AMPA-type glutamate receptors. These results show that Arc EVs mediate an intercellular form of synaptic plasticity that may be critical for memory consolidation and reveals a new neuronal EV biogenesis pathway.

neuroscience↗

bioRxiv2022

Arc Regulates a "Second-Guessing" Cognitive Bias During Naturalistic Foraging

Foraging involves innate decision heuristics that are adapted for the wild but can cause economically suboptimal cognitive biases in some contexts. The mechanisms underlying cognitive biases are poorly understood but are likely genetic. Here, we investigate foraging in fasted mice using a naturalistic paradigm and uncover an innate "second-guessing" cognitive bias that involves repeatedly investigating an empty former food patch instead of consuming available food. Second-guessing prevents mice from maximizing feeding benefits in the task. Since learning and memory are involved, we tested roles for the synaptic plasticity gene, Arc, and found that Arc-/- mice show a specific lack of second-guessing. Arc-/- males reap benefits by increasing food consumption. Unsupervised machine learning decompositions of foraging show that Arc affects discrete, stereotyped foraging sequences that we call modules within a rich naturalistic behavioral landscape. Thus, our study reports a second- guessing cognitive bias, ethological roles for Arc in naturalistic foraging, and links between genetically determined foraging modules and cognitive bias in decision making.

neuroscience↗