Biology subjects

Rhee, J. Y.

Publications and source records attributed to Rhee, J. Y..

3 recordsLinked to original sources

bioRxiv2025

A vector-based strategy for olfactory navigation in Drosophila

Odors serve as essential cues for navigation. Although tracking an odor plume has been modeled as a reflexive process, it remains unclear whether animals can use memories of their past odor encounters to infer the spatial structure of their chemical environment or their location within it. Here we developed a virtual-reality olfactory paradigm that allows head-fixed Drosophila to navigate structured chemical landscapes, offering insight into how memory mechanisms shape their navigational strategies. We found that flies track an appetitive odor corridor by following its boundary, alternating between rapid counterturns to exit the plume and directed returns to its edge. Using a combination of behavioral modeling, functional calcium imaging, and neural perturbations, we demonstrate that this edge-tracking strategy relies on vector-based computations within the Drosophila central complex in which flies store and dynamically update memories of the direction to return them to the plumes boundary. Consistent with this, we find that FC2 neurons within the fan-shaped body, which encode a flys navigational goal, signal the direction back to the odor boundary when flies are outside the plume. Together, our studies suggest that flies leverage the plumes boundary as a dynamic landmark to guide their navigation, analogous to the memory-based strategies other insects use for long-distance migration or homing to their nests. Plume tracking thus uses components of a conserved navigational toolkit, enabling flies to use memory mechanisms to navigate through a complex shifting chemical landscape.

neuroscience↗

bioRxiv2023

Neural correlates of visual object recognition in rats

Invariant object recognition--the ability to recognize objects across size, rotation, or context--is fundamental for making sense of a dynamic visual world. Although initially believed to be unique to primates due to its complexity, emerging evidence suggests rodents, too, can recognize objects across a range of identity-preserving transformations. Here, we describe a comprehensive pipeline for investigating visual behavior in rats, from high-throughput training to cellular resolution imaging in awake, head-fixed animals. Using this suite of tools, we demonstrate that rats excel in visual object recognition and explore potential neural pathways which may support this capacity. We leverage our optical approach to systematically profile multiple visual areas with responses to a range of stimulus types recorded in the same neurons. Primary and higher-order areas of rat visual cortex exhibit a hierarchical organization consistent with a role in visual object recognition. However, marked deviations from the functional organization of primate visual cortex suggest species-specific differences in the neural circuits underlying visual object recognition. This work reinforces the notion that rats possess sophisticated visual abilities and offers the technical foundation for their use as a powerful model to link neuronal responses to perception and behavior.

neuroscience↗

bioRxiv2020

Rats strategically manage learning during perceptual decision making

Balancing the speed and accuracy of decisions is crucial for survival, but how organisms manage this trade-off during learning is largely unknown. Here, we track this trade-off during perceptual learning in rats and simulated agents. At the start of learning, rats chose long reaction times that did not optimize instantaneous reward rate, but by the end of learning chose near-optimal reaction times. To understand this behavior, we analyzed learning dynamics in a recurrent neural network model of the task. The model reveals a fundamental trade-off between instantaneous reward rate and perceptual learning speed, putting the goals of learning quickly and accruing immediate reward in tension. We find that the rats strategy of long initial responses can dramatically expedite learning, yielding higher total reward over task engagement. Our results demonstrate that prioritizing learning can be advantageous from a total reward perspective, and suggest that rats engage in cognitive control of learning.

neuroscience↗