Biology subjects

Kim, G.-H.

Publications and source records attributed to Kim, G.-H..

3 recordsLinked to original sources

bioRxiv2025

Cold sensing by a glutamate receptor drives avoidance behavior in Drosophila larvae

The ability to sense and avoid noxious environments is essential for animal survival; yet, how this is achieved at the behavioral, neuronal, and molecular levels is not well understood. Here, we use Drosophila larvae as a model to investigate how animals sense and avoid cold temperatures. By implementing custom-built thermoelectric devices capable of delivering rapid and precise thermal stimuli, we find that cold delivered to the larval head evokes robust escape behavioral responses. We identify a group of head-located cold-sensitive neurons as necessary and sufficient for such avoidance responses. We further demonstrate that the kainate-type glutamate receptor Clumsy acts as a novel cold sensor required for head cold sensitivity. Knockdown of Clumsy in head cold-sensing neurons suppresses their cold sensitivity. Heterologous expression of Clumsy confers cold sensitivity. Our results show that Drosophila larvae have evolved the capacity to detect and avoid cold temperatures through a previously uncharacterized cold-sensing mechanism.

neuroscience↗

bioRxiv2025

Parietal top-down projections balance flexibility and stability in adaptive learning

Rapid behavioral adaptation requires the brain to solve a fundamental computational dilemma: how to flexibly update learned rules while maintaining stable motor performance. This flexibility-stability trade-off is central to cognitive function and artificial intelligence, yet its neural circuit basis is poorly understood. Here, we identify the circuit architecture that coordinates this balance. Using a within-session auditory reversal learning task combined with circuit-specific manipulations in mice, we demonstrate that the posterior parietal cortex (PPC) orchestrates adaptive learning through two parallel, anatomically distinct pathways to the auditory cortex (AC) and inferior colliculus (IC). These two circuits perform a double dissociation of function: the PPC-to-AC circuit facilitates flexible rule updating by encoding dynamic stimulus-outcome contingencies, while the PPC-to-IC circuit preserves stable action execution across changing rules. A feedforward network model further demonstrates that segregated stable and flexible top-down projections are necessary and sufficient for rapid reversal learning. This parallel architecture segregates adaptive and stable computations into distinct circuits, providing a mechanistic framework for cognitive flexibility and offering potential insight into conditions where this balance is disrupted, such as obsessive-compulsive disorder and schizophrenia.

neuroscience↗

bioRxiv2020

Development of a diamide resistance diagnostic method using LAMP based on a resistance-specific indel in ryanodine receptors for Spodoptera exigua (Lepidoptera: Noctuidae)

Recently, resistance to diamide insecticides (IRAC group 28) has been reported in various lepidopteran pests, including Spodoptera exigua. In the present study, susceptibility of six field populations was evaluated to two diamide insecticides: chlorantraniliprole and flubendiamide. The bioassay test for resistance revealed a high level of diamide resistance and helped to select a diamide resistant (Di-R) strain, whose LC50 values against chlorantraniliprole and flubendiamide were 28,950- and 135,286-fold higher, respectively, than those of susceptible strains. In the ryanodine receptor, instead of the G4946E mutation, one of the well-known diamide resistance mechanisms, we found a I4790M mutation and identified the resistance allele-specific indel linked to it. Resistance allele diagnostic primers were designed using this distinct region and applied in loop-mediated isothermal amplification (LAMP) and general PCR. LAMP accurately detected the specific indel when conducted for 2 h at temperature range from 63 {degrees}C to 65 {degrees}C and using four LAMP primers; its efficiency was further amplified by an additional loop primer. A broad range of DNA concentrations was workable in the LAMP assay, with the minimum detectable DNA concentration of 100 pg. The new DNA releasing method used for the LAMP assay consisted of 5 min of incubation of a larva or adult tissue at 95{degrees}C. The entire diagnostic process, which included the DNA releasing technique and LAMP, lasted only 100 min. This simple and accurate LAMP assay can be applied to monitor diamide resistance and for integrated resistance management of S. exigua in the field.

ecology↗