Published works affiliated with MarkoLab

Inverse Reinforcement Learning with Switching Rewards and History Dependency for Characterizing Animal Behaviors

Ke J, Wu F, Wang J, Markowitz JE, Wu A.

arXiv January, 2025

Abstract

Traditional approaches to studying decision-making in neuroscience focus on simplified behavioral tasks where animals perform repetitive, stereotyped actions to receive explicit rewards. While informative, these methods constrain our understanding of decision-making to short timescale behaviors driven by explicit goals. In natural environments, animals exhibit more complex, long-term behaviors driven by intrinsic motivations that are often unobservable. Recent works in time-varying inverse reinforcement learning (IRL) aim to capture shifting motivations in long-term, freely moving behaviors. However, a crucial challenge remains: animals make decisions based on their history, not just their current state. To address this, we introduce SWIRL (SWitching IRL), a novel framework that extends traditional IRL by incorporating time-varying, history-dependent reward functions. SWIRL models long behavioral sequences as transitions between short-term decision-making processes, each governed by a unique reward function. SWIRL incorporates biologically plausible history dependency to capture how past decisions and environmental contexts shape behavior, offering a more accurate description of animal decision-making. We apply SWIRL to simulated and real-world animal behavior datasets and show that it outperforms models lacking history dependency, both quantitatively and qualitatively. This work presents the first IRL model to incorporate history-dependent policies and rewards to advance our understanding of complex, naturalistic decision-making in animals.

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Other Publications

An optogenetics-compatible red fluorescent calcium indicator with negligible blue light photoactivation

Zhang X, Addison BR, Ulutas EZ, Deng CM, Doshi S, Nabhan S, Emanuel AJ, Markowitz JE, Koveal D

BioRxiv March, 2026

High-resolution in vivo kinematic tracking with injectable fluorescent nanoparticles

Ulutas EZ, Pradhan A, Koveal D, Markowitz JE.

Science Advances October, 2025

Act natural: a review of new methods for assessing dopamine’s role in natural behavior

Markowitz JE.

Current Opinion in Behavioral Sciences May, 2025