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Hahnloser, R. H.

Publications and source records attributed to Hahnloser, R. H..

4 recordsLinked to original sources
bioRxiv2025

Estimating the motor exploration in reinforcement learning

What motor exploration strategies do animals use to learn a skill from rewards? Reinforcement learning theory provides no guidance for estimating motor exploration -- the behavioral component aimed at discovering better strategies. Inspired by the brains modular organization, we postulate a latent learner that explores via an additive source of ideal randomness it injects into behavior. Assuming the learner is ignorant of other motor components, which is sub-optimal by design, evolutionary fitness argues that these should display mainly non-ideal variability. We test this recipe for behavior decomposition in songbirds subjected to a vocal pitch conditioning task. The explorative component we estimate from vocalizations accounts for the motor contribution of a basal ganglia pathway and the other behavioral component accounts for birds suboptimal learning trajectories. This congruence between normative exploration and brain organization suggests that the evolutionary pressure for behavioral optimality is lesser than to learn from purely random trials.

neuroscience↗
bioRxiv2022

Multimodal system for recording individual-level behaviors in songbird groups

The implicit goal of longitudinal observations of animal groups is to identify individuals and to reliably detect their behaviors, including their vocalizations. Yet, to segment fast behaviors and to extract individual vocalizations from sound mixtures remain challenging problems. Promising approaches are multimodal systems that record behaviors with multiple cameras, microphones, and animal-borne wireless sensors. The instrumentation of these systems must be optimized for multimodal signal integration, which is an overlooked steppingstone to successful behavioral tracking. We designed a modular system (BirdPark) for simultaneously recording small animals wearing custom low-power frequency-modulated radio transmitters. Our custom software-defined radio receiver makes use of a multi-antenna demodulation technique that eliminates data losses due to radio signal fading and that increases the signal-to-noise ratio of the received radio signals by 6.5 dB compared to best single-antenna approaches. Digital acquisition relies on a single clock, allowing us to exploit cross-modal redundancies for dissecting rapid behaviors on time scales well below the video frame period, which we demonstrate by reconstructing the wing stroke phases of free-flying songbirds. By separating the vocalizations among up to eight vocally interacting birds, our work paves the way for dissecting complex social behaviors.

animal behavior and cognition↗
bioRxiv2020

Fast retrograde access to projection neuron circuits underlying vocal learning in songbirds

Understanding the structure and function of neural circuits underlying speech and language is a vital step towards better treatments for diseases of these systems. Songbirds, among the few animal orders that share with humans the ability to learn vocalizations from a conspecific, have provided many insights into the neural mechanisms of vocal development. However, research into vocal learning circuits has been hindered by a lack of tools for rapid genetic targeting of specific neuron populations to meet the quick pace of developmental learning. Here, we present a new viral tool that enables fast and efficient retrograde access to projection neuron populations. In zebra finches, Bengalese finches, canaries, and mice, we demonstrate fast retrograde labeling of cortical or dopaminergic neurons. We further demonstrate the suitability of our construct for detailed morphological analysis, for in vivo imaging of calcium activity, and for multicolor brainbow labeling.

neuroscience↗