utilizing-reconfigurable-maze-system-to-enhance-reproducibility

Utilizing a Reconfigurable Maze System to Enhance the Reproducibility of Spatial Navigation Tests in Rodents

Several maze shapes are used to test spatial navigation performance and behavioral phenotypes. Traditionally, each experiment requires a unique maze ...

utilizing-vmtracking-to-improve-accuracy-multi-animal-pose-estimation

Utilizing vmTracking to Improve the Accuracy of Multi-Animal Pose Estimation in Rodent Social Behavior Studies

In social behavior research using rodents, there is a growing demand for evaluating more natural interactive behaviors under freely moving conditions. ...

Doshisha University

The Fawn-Hooded (FH) rat carries a gene mutation that results in a dysfunctional serotoninergic system. However, previous studies have reported differing features between the FH/Wjd and FH/Har strains. We aimed to compare the behavioural and neurobiological features of FH/HamSlc rats with those of Fischer 344 rats. We performed the open field, elevated minus-maze, Y-maze spontaneous alternation, and forced swim tests to investigate behavioural alterations. We also assessed neurobiological characteristics by quantifying monoamines and their related compounds in the prefrontal cortex, hippocampus, and striatum using high-performance liquid chromatography with an electrochemical detection system. FH/HamSlc rats showed hyperactivity and a high impulsivity tendency in the open field and the elevated minus maze test, but no cognitive dysfunction. In addition, the hyperactivity was suppressed immediately after the forced swim test. FH/HamSlc rats showed low dopamine levels, but high dopamine turnover in the striatum. Serotonin and noradrenaline levels were low in the prefrontal cortex and the hippocampus of FH/HamSlc rats, but high serotonin turnover was observed in the prefrontal cortex, hippocampus, and striatum. FH/HamSlc rats show (1) mania-like behavioural characteristics that are different from those of other strains of FH rats; (2) stimulus dependent suppression of hyperactivity similar to the clinical findings that exercise alleviates the symptoms of bipolar disorder; and (3) monoaminergic dysregulation such as monoamine imbalance and hyperturnover that may be associated with mania-related behavioural characteristics. Thus, the FH/HamSlc rat is a new animal model for mania including bipolar disorder.

A new inbred strain of Fawn-Hooded rats demonstrates mania-like behavioural and monoaminergic abnormalities.

Multiple mazes are routinely used to test the performance of animals because each has disadvantages inherent to its shape. However, the maze shape cannot be flexibly and rapidly reproduced in a repeatable and scalable way in a single environment. Here, to overcome the lack of flexibility, scalability, reproducibility, and repeatability, we develop a reconfigurable maze system that consists of interlocking runways and an array of accompanying parts. It allows experimenters to rapidly and flexibly configure a variety of maze structures along the grid pattern in a repeatable and scalable manner. Spatial navigational behavior and hippocampal place coding were not impaired by the interlocking mechanism. As a proof-of-principle demonstration, we demonstrate that the maze morphing induces location remapping of the spatial receptive field. The reconfigurable maze thus provides flexibility, scalability, repeatability, and reproducibility, therefore facilitating consistent investigation into the neuronal substrates for learning and memory and allowing screening for behavioral phenotypes.

The Reconfigurable Maze Provides Flexible, Scalable, Reproducible, and Repeatable Tests.

Animal adaptation to environmental goals to pursue rewards is modulated by dopamine. However, the role of dopamine in the hippocampus, involved in spatial navigation, remains unclear. Here, we studied dopaminergic inputs from the ventral tegmental area (VTA) to the hippocampus, focusing on spatial goal persistence and adaptation. Mice with VTA dopaminergic lesions struggled to locate and update learned reward locations in a circular maze with dynamic reward locations, emphasizing the importance of VTA dopaminergic neurons in the persistence and adaptation of spatial memory. Further, these deficits were accompanied by motor impairments or motivational loss even when dopamine receptors in the dorsal hippocampus were selectively blocked. Stimulation of VTA dopaminergic axons within the dorsal hippocampus enhanced the mice's ability to adapt to changing reward locations. These findings provide insights into the contribution of dopaminergic inputs within the hippocampus to spatial goal adaptation.

Optogenetic activation of the ventral tegmental area-hippocampal pathway facilitates rapid adaptation to changes in spatial goals.

In multi-animal tracking, addressing occlusion and crowding is crucial for accurate behavioral analysis. However, in situations where occlusion and crowding generate complex interactions, achieving accurate pose tracking remains challenging. Therefore, we introduced virtual marker tracking (vmTracking), which uses virtual markers for individual identification. Virtual markers are labels derived from conventional markerless multi-animal tracking tools, such as multi-animal DeepLabCut (maDLC) and Social LEAP Estimates Animal Poses (SLEAP). Unlike physical markers, virtual markers exist only within the video and attribute features to individuals, enabling consistent identification throughout the entire video while keeping the animals markerless in reality. Using these markers as cues, annotations were applied to multi-animal videos, and tracking was conducted with single-animal DeepLabCut (saDLC) and SLEAP's single-animal method. vmTracking minimized manual corrections and annotation frames needed for training, efficiently tackling occlusion and crowding. Experiments tracking multiple mice, fish, and human dancers confirmed vmTracking's variability and applicability. These findings could enhance the precision and reliability of tracking methods used in the analysis of complex naturalistic and social behaviors in animals, providing a simpler yet more effective solution.

ArticleTotal : 2	Year
Publication title	2022
Publication title	2025

Article	Year
A new inbred strain of Fawn-Hooded rats demonstrates mania-like behavioural and monoaminergic abnormalities. IBRO reports\| PubMed ID: 31763490	2019
The Reconfigurable Maze Provides Flexible, Scalable, Reproducible, and Repeatable Tests. iScience\| PubMed ID: 31918045	2020
Optogenetic activation of the ventral tegmental area-hippocampal pathway facilitates rapid adaptation to changes in spatial goals. iScience\| PubMed ID: 38089585	2023
vmTracking enables highly accurate multi-animal pose tracking in crowded environments. PLoS biology\| PubMed ID: 39928646	2025

Hirotsugu Azechi

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