Cylinder device for detecting anterior limb asymmetry of murine animal and detection method

Abstract

The invention discloses a cylinder device for detecting anterior limb asymmetry of murine animals and a detection method. The cylinder device is composed of a double-layer transparent cylinder, a top wide-angle infrared camera, a detachable transparent touch-sensitive lining, a base rapid lock catch and a data processing unit. The lining coaxially overlaps the capacitor partition array and the ultrathin force-sensitive film, and outputs a touch position and a load-bearing signal in real time; the top camera synchronously collects videos, and forelimb sides and light / load-bearing touch are judged through timestamp fusion. The inertial measurement unit is arranged in the system to eliminate false signals, consumable sterilization replacement is supported, and after the set touch times or the statistical time is reached, automatic ending is achieved, and a report is generated. Compared with previous experimental equipment, the experimental device can intelligently obtain behavioral data of rats, judge forelimb side and light / load-bearing touch and eliminate false signals, and the behavioral data detection accuracy is high.

Description

Technical Field

[0001] This invention relates to the field of animal behavior testing equipment, specifically to a cylindrical device and testing method for detecting forelimb asymmetry in rodents. Technical Background

[0002] The Cylinder Test has been recognized as one of the "gold standards" for evaluating unilateral motor deficits in rodents since the 1990s. It is used to assess the degree of motor dysfunction after unilateral brain injury, monitor forelimb motor compensation mechanisms in neurodegenerative disease models, and verify the effectiveness of neuroprotective or rehabilitation interventions. The principle is that when rodents are placed in a vertical, transparent cylinder, they spontaneously stand upright and use their forelimbs to touch the cylinder wall for balance. If degenerative or ischemic damage occurs in one brain region, the frequency of contact with the cylinder wall and the weight-bearing ratio of the contralateral forelimb decrease significantly. The resulting left-right asymmetry index quantitatively reflects the degree of motor function loss. This index is significantly correlated with dopaminergic neuron loss, Aβ deposition, and infarct volume in models of Parkinson's disease, Alzheimer's disease, and stroke, and is therefore widely used for drug efficacy verification, gene function analysis, and pre- and post-operative efficacy tracking.

[0003] Traditional cylindrical experimental setups consist of only a transparent acrylic cylinder and a camera. Researchers must visually determine "left / right / bilateral" contact events frame by frame in the playback video. This process is time-consuming, prone to subjective bias, and data cannot be compared across different laboratories due to differences in lighting angles, cylinder diameter-to-height ratios, and evaluation thresholds. This severely restricts the need for high-throughput, multi-center research. As research on neurodegenerative diseases advances towards a "chronic, minimally invasive, early intervention" approach, higher demands are placed on the sensitivity, spatiotemporal resolution, and data dimensionality of forelimb asymmetry detection. The existing technology has at least five defects: (1) manual scoring relies on experience and has a low consistency coefficient across operators; (2) single-view imaging is easily affected by abdominal obstruction and reflection from the cylinder wall, resulting in high rates of missed and false judgments; (3) it cannot distinguish between two mechanical events, "light touch probing" and "weight support," causing early minor motor impairments to be submerged in background noise; (4) it lacks real-time signal output and cannot perform millisecond-level time locking with other synchronous recordings (such as electrophysiology, optogenetics, and calcium imaging); (5) commercially available cylinders only provide containers, without sensors, algorithms, or cloud interfaces, making it difficult to meet the current needs of automated, intelligent, and large-scale experiments. Therefore, under the premise of maintaining the natural behavior ecology of animals, developing a cylinder system that integrates tactile sensing, multi-view vision, and edge computing to achieve highly sensitive, objective, and real-time acquisition and analysis of forelimb touch events has become a technical problem that urgently needs to be solved in the field of neurobehavioral detection. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a cylindrical device and detection method for detecting forelimb asymmetry in rodents. Through intelligent video analysis and mechanical measurement modules, it identifies, classifies, and counts forelimb touches in mice, distinguishing between light and heavy touches. It supports setting target detection completion conditions to complete forelimb asymmetry inspection experiments in both mice and rats. This application provides an intelligent tactile-visual fusion cylindrical system for detecting forelimb asymmetry in experimental animals, aiming to solve problems such as the strong subjectivity of manual scoring in existing cylindrical experiments, easy omissions in video testing, and insufficient sensitivity to chronic injuries.

[0005] The objective of this invention can be achieved through the following technical solutions: A cylindrical device and method for detecting forelimb asymmetry in rodents include: a double-layered transparent cylindrical wall, with an outer layer being a transparent rigid cylinder and an inner layer being a removable transparent touch-sensitive liner. The touch-sensitive liner is coaxially superimposed with a transparent capacitive sensing film partition array and an ultra-thin force-sensitive film; a top imaging and supplementary lighting module, including a wide-angle camera and a ring-shaped near-infrared supplementary light mounted on the top of the cylinder; a base quick-lock and signal interface, with an inertial measurement unit built into the integrated support base; a data acquisition and fusion processing unit, used to simultaneously acquire touch and force signals and video signals output from the touch-sensitive liner, and to determine the side of the touched forelimb and its load-bearing status based on timestamp fusion; and an automatic analysis and output module, used to calculate the forelimb usage ratio and asymmetry index, and generate an experimental report. The double-layered transparent cylindrical wall has an outer layer being a rigid support cylinder and an inner layer being a removable transparent touch-sensitive liner. This liner is coaxially superimposed with a transparent capacitive sensing film partition array and an ultra-thin force-sensitive film, with each partition independently outputting touch and load-bearing signals.

[0006] Furthermore, the touch-sensitive liner is designed to be replaceable as a consumable material and can be sterilized by high temperature or chemical means.

[0007] Furthermore, the data acquisition and fusion processing unit includes a visual analysis system and a mechanical acquisition system; the visual analysis system of the visual analysis module is based on an image AI algorithm, which is trained by acquiring label images of mice and rats touching the inner wall of the cylinder, and automatically captures the front paws of mice and rats to determine whether they are touching the inner lining.

[0008] Furthermore, the base has a built-in inertial measurement unit for determining that the verticality error of the cylinder is <1° and for detecting whether there is a continuous sway of >0.2g.

[0009] Furthermore, the top wide-angle infrared camera, in conjunction with a ring-shaped near-infrared fill light and a polarizer, enables reflection-free overhead shooting; Furthermore, the base adopts a quick-locking buckle and a touch-sensitive inner lining with an integrated electromechanical hidden interface, and has a built-in IMU to eliminate false signals from device shaking; the data acquisition and fusion processing unit synchronizes touch-sensitive events and video posture estimation with timestamps, automatically determines the forelimb side and distinguishes between light touch and weight-bearing touch; Furthermore, the automatic analysis and output module can statistically analyze the number of times, proportions, and asymmetry index of the left and right limbs and both limbs touching the wall in real time, and can automatically end the experiment after setting a threshold for the number of touches, generating a standardized and reproducible report.

[0010] Furthermore, the automatic analysis and output module has the function of setting a threshold for the number of touches or setting an experimental time limit, and automatically ending the experiment after the threshold is reached.

[0011] Furthermore, the quick-locking base includes a double-layer transparent cylindrical outer layer bottom magnetic attraction and an integrated bracket bottom magnetic attraction, and the signal interface is a magnetic brass contact spring pin pogo pin connector. Beneficial effects

[0012] 1. This invention utilizes visual and force modules and intelligent AI algorithms to intelligently identify, classify, and count touches on the forelimbs of rats and mice. The force detection module can eliminate false touches, distinguish between light and heavy touches, and provides multi-dimensional and information-rich behavioral data. The device can automatically and accurately conduct behavioral experiments on rats. This system is objective, automatic, and highly sensitive, suitable for long-term behavioral assessment of unilateral sensorimotor injury models.

[0013] 2. The force detection module of this invention is transparent and washable. The outer layer and bottom of the cylinder are magnetically attached, making it easy to install and disassemble, and facilitating cleaning and deodorization of the cylinder after the experiment.

[0014] 3. This invention can improve the efficiency of batch experiments and reduce manual operation by setting start and end conditions for the experiment and completing the experiment according to the conditions, and reminding the operator.

[0015] 4. This invention can determine whether the cylinder is tilted or shaking when placed upright by an inertial measurement unit, thereby improving the accuracy of the measurement. Attached Figure Description

[0016] The following figures are provided only to illustrate the features and examples of the present invention, and are not intended to limit the scope of the invention.

[0017] Figure 1 This is a schematic diagram of the overall invention.

[0018] Figure 2 This is a general sectional view of the present invention.

[0019] Figure 3 This is a side view of the outer cylinder of the present invention.

[0020] Figure 4 This is a schematic diagram of the bracket of the present invention.

[0021] Figure 5 This is a schematic diagram of the partitioned array of transparent capacitive sensing film adhered to the liner of the present invention.

[0022] In the picture: 1. Bracket; 2. Outer cylinder; 3. Wide-angle camera; 4. Infrared light; 5. Inner liner; 6. Inertial measurement unit; 7. Magnetic attraction. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0024] like Figures 1-2 As shown, a cylindrical device and detection method for detecting forelimb asymmetry in rodents include: a double-layer transparent cylindrical wall, an integrated support, a top imaging and supplementary lighting module, a base quick-lock and signal interface, a data acquisition and fusion processing unit, and an automatic analysis and output module.

[0025] Structural assembly: The outer cylinder 2 of the double-layered cylindrical structure is made of high-transparency acrylic tube with an outer diameter of 200mm, a height of 300mm, and a wall thickness of 5mm. Eight positioning holes are machined into the bottom, and magnetic 7 is placed inside each hole. The inner liner 5 is a 0.5mm thick PET substrate with a transparent conductive layer formed by vacuum sputtering ITO on its surface. It is then etched with a femtosecond laser into 40 rectangular sections, each 6mm vertically and 8mm horizontally; the section line width is 0.2mm, and the light transmittance is >88%. A 0.1mm thick piezoelectric force-sensitive film (range 0–200g, threshold 5g) is bonded on top of the ITO layer. A 3mm thick PET reinforcing ring is hot-pressed onto the top and bottom of the inner liner, with a φ2mm gold-plated pogo pin embedded on each ring as an electrical signal contact.

[0026] The upper crossbeam of bracket 1 has a hole in the middle for mounting a wide-angle distortion-free lens camera 3. The lens is surrounded by an infrared lamp 4 consisting of a ring array of 12 850nm infrared LEDs. A linear polarizer (45°) is added in front of the LEDs, and a 90° cross polarizer is added in front of the lens to eliminate reflections.

[0027] The integrated bracket base is made of CNC machined aluminum alloy, with an outer diameter of 220mm and a height of 10mm. The support rod and crossbeam are welded to the base from aluminum alloy. The upper surface has 8 sets of magnetic attraction corresponding to the outer layer of the cylinder, and a pogo-pin combination interface corresponding to the inner reinforcing ring, enabling quick detachment in 1 second. The base has a built-in 9-axis inertial measurement unit, model IMU BMI160.

[0028] Detection method: S1: After the system is powered on, it first performs an IMU self-test. If it detects a continuous shaking of >0.2g or a tilt of more than 1°, it will pause data acquisition and issue a prompt.

[0029] S2: Place the mouse into the cylinder and activate touch sensitivity and video synchronous acquisition. The touch-sensitive liner scans the capacitance values ​​of 40 zones at 1kHz, and the force-sensitive film samples synchronously. When the capacitance change of any zone is >3pF and the force-sensitive output is >5g, it is marked as a "touch event" and stamped with a millisecond-level timestamp.

[0030] S3: The camera captures video at 60fps, with each frame header containing a timestamp from the same clock field. Hardware-triggered visual recognition is used to determine forelimb lateral alignment and weight-bearing. S4: Video image analysis uses Jetson Nano to run a lightweight HRNet posture model (3 key points: nose tip, left wrist, right wrist), aligning 2D coordinates with touch events: if the Euclidean distance between the center of the touch zone and any wrist key point is <15mm and the force value is >5g, it is determined to be a weighted touch; if the distance is <15mm but the force value is <5g, it is a light touch.

[0031] S5: Real-time statistics refresh the curve every 10 seconds; when the cumulative load-bearing touch on one side reaches 20 times or the experiment duration reaches 10 minutes, the system automatically stops and generates a report, including the original data and the force-time diagram and height distribution diagram in PDF format.

[0032] Sterilization process: The liner can be soaked in 2% peracetic acid for 30 minutes or sterilized by autoclaving at 134°C for 10 minutes. After 50 cycles, the ITO impedance change is <5%, still meeting the sensitivity requirements.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A cylindrical device for detecting forelimb asymmetry in rodents, characterized in that: The system includes a double-layered transparent cylindrical wall, an integrated support frame, a top imaging and lighting module, a base quick-locking and signal interface, a data acquisition and fusion processing unit, and an automatic analysis and output module. The double-layered transparent cylindrical wall consists of an outer transparent rigid cylinder and an inner removable transparent touch-sensitive liner. The touch-sensitive liner is coaxially stacked with a transparent capacitive sensing film array and an ultra-thin force-sensitive film. The top imaging and lighting module includes a wide-angle camera and a ring-shaped near-infrared lighting lamp mounted on the top of the cylinder. The base quick-locking and signal interface includes a magnetic bottom magnetic attraction and a signal magnetic attraction brass contact spring pin pogo pin connector. The base has a built-in inertial measurement unit. The data acquisition and fusion processing unit synchronously acquires touch and force signals and video signals output from the touch-sensitive liner, and determines the forelimb side and load-bearing status based on timestamp fusion. The automatic analysis and output module calculates the forelimb usage ratio and asymmetry index, and generates an experimental report.

2. The cylindrical device for detecting forelimb asymmetry in rodents according to claim 1, characterized in that: The data acquisition and fusion processing unit includes a visual analysis system and a mechanical acquisition system. The visual analysis system of the visual analysis module is based on an image AI algorithm. It is trained by acquiring images of rats and mice touching the inner wall of the cylinder and automatically captures the front paws of rats and mice to determine whether they are touching the inner lining.

3. The cylindrical device for detecting forelimb asymmetry in rodents according to claim 1, characterized in that, The base has a built-in inertial measurement unit to determine if the cylinder's verticality error is less than 1° and to detect if there is a continuous sway of >0.2g.

4. The cylindrical device for detecting forelimb asymmetry in rodents according to claim 1, characterized in that, The quick-locking base includes a double-layer transparent cylindrical outer layer bottom magnetic attraction and an integrated bracket bottom magnetic attraction, and the signal interface is a magnetic brass contact spring pin pogo pin connector.

5. A method for detecting forelimb asymmetry in rodents, comprising the following steps: 1) After the system is powered on, it first performs an IMU self-test. If it detects a continuous shaking of >0.2g or a tilt of more than 1°, it will pause data acquisition and issue a prompt. 2) Place the mouse in the cylinder, turn on touch sensitivity and video synchronous acquisition, scan the capacitance values ​​of 40 zones at 1kHz, and sample the force-sensitive membrane synchronously; when the capacitance change of any zone is >3pF and the force-sensitive output is >5g, it is marked as a "touch event" and stamped with a millisecond-level timestamp; 3) The camera captures video at 60fps, with each frame header containing a timestamp from the same clock field. Hardware-triggered visual recognition is used to determine forelimb lateral alignment and weight-bearing. 4) Video image analysis uses Jetson Nano to run a lightweight HRNet posture model (3 key points: nose tip, left wrist, right wrist). The 2D coordinates are aligned with the touch event. If the Euclidean distance between the center of the touch zone and any wrist key point is <15mm and the force value is >5g, it is determined to be a weighted touch. If the distance is <15mm but the force value is <5g, it is a light touch. 5) The curve is refreshed every 10 seconds in real time. When the cumulative load-bearing touch on one side reaches 20 times or the experiment duration reaches 10 minutes, the system will automatically stop and generate a report.

6. The detection method for detecting forelimb asymmetry in rodents according to claim 5, characterized in that: The lining is soaked in 2% peracetic acid for 30 minutes or sterilized by high-pressure steam at 134°C for 10 minutes. After 50 cycles of use, the ITO impedance change is <5%.

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