Abstract
.Significance: We propose a customized animal-specific head cap and an near-infrared spectroscopy (NIRS) system to obtain NIRS signals in mobile small animals. NIRS studies in mobile small animals provide a feasible solution for comprehensive brain function studies.Aim: We aim to develop and validate a multichannel NIRS system capable of performing functional brain imaging along with a closed-box stimulation kit for small animals in mobile conditions.Approach: The customized NIRS system uses light-weight long optical fibers, along with a customized light-weight head cap to securely attach the optical fibers to the mouse. A customized stimulation box was designed to perform various stimuli in a controlled environment. The system performance was tested in a visual stimulation task on eight anesthetized mice and eight freely moving mice.Results: Following the visual stimulation task, we observed a significant stimulation-related oxyhemoglobin (HbO) increase in the visual cortex of freely moving mice during the task. In contrast, HbO concentration did not change significantly in the visual cortex of anesthetized mice.Conclusions: We demonstrate the feasibility of a wearable, multichannel NIRS system for small animals in a less confined experimental design.
Highlights
Small animal models have made significant contributions to enhancing our understanding of many different types of neurological disorders, including Alzheimer’s disease, stroke, and Parkinson’s disease.[1,2,3,4] Such models allow for experiments in which various parameters can be tightly controlled, from the type of disease to the stimulus provided to the animal
The grand average of the HbO in the freely moving group slightly increased in the visual cortex during the task period, whereas that in the anesthesia group did not show substantial changes
The HbO response increased in the visual cortex when visual stimulation was performed for freely moving animals
Summary
Small animal models have made significant contributions to enhancing our understanding of many different types of neurological disorders, including Alzheimer’s disease, stroke, and Parkinson’s disease.[1,2,3,4] Such models allow for experiments in which various parameters can be tightly controlled, from the type of disease to the stimulus provided to the animal. Near-infrared spectroscopy (NIRS) is a proven neuroimaging technique for non-invasive and real-time monitoring of cerebral oxygenation changes.[10] It offers advantages over other modalities such as cost-effectiveness compared with PET and fMRI and greater robustness for motion artifacts than electroencephalogram.[11] Most importantly, NIRS can be constructed in the form of wearable probes that do not obstruct natural movements.[12,13] Due to these advantages, wearable NIRS probes have already been developed and used for animals.[14,15,16,17,18,19,20,21,22] animals are still stressed by fixation, which may subsequently impact brain function,[23,24] whereas the use of anesthesia restricts specific behavioral and cognitive experiments since anesthetics strongly modulate the functional properties of cortical neurons.[25,26,27,28] Further, these studies mainly focus on one or two candidate brain regions and are biased toward regions previously shown or predicted to be involved in a given behavior. A new type of NIRS implementation that is nonconstraining for an awake animal and robust to potential motion artifacts and allows for real-time functional imaging is required
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
