Robust and Reproducible Awake Mouse fMRI with Controlled Movement May Reduce Perceived Stress
Presented During: Poster Session 3
Friday, June 27, 2025: 01:45 PM - 03:45 PM
Friday, June 27, 2025: 01:45 PM - 03:45 PM
Presented During: Poster Session 4
Saturday, June 28, 2025: 01:45 PM - 03:45 PM
Saturday, June 28, 2025: 01:45 PM - 03:45 PM
Poster No:
1376
Submission Type:
Abstract Submission
Authors:
Lauren Daley1, Wen-Ju Pan1, Shella Keilholz1
Institutions:
1Emory University/Georgia Institute of Technology, Atlanta, GA
First Author:
Co-Author(s):
Introduction:
Since its inception, functional MRI provides researchers with a whole-brain, non-invasive measure of neural activity (1). From fMRI, preserved patterns of functional connectivity (FC) and neural dynamics have been observed across species (2). Awake animal fMRI offers scientists the opportunity to longitudinally study and test invasive pathological interventions. Despite its value, animal fMRI magnifies existing problems in clinical fMRI and has its own unique challenges. To provide a truly analogous pre-clinical equivalent, it is imperative to reduce stress response, minimize motion's impact on the signal, and to avoid anesthesia-dependent signal changes. This work presents a robust, reproducible, and stress-minimizing protocol for awake mouse ZTE fMRI, that addresses key issues facing awake studies: 1) Motion - Studies often report excluding significant portions of originally acquired data or entire subject data (3). This sensitivity to motion is exemplified in animal fMRI, as an animal is very likely to move (4). Zero TE sequence use radial k-space sampling, oversampling k-space center, minimizing excessive motion effects. 2) Stress - animals are easily stressed but the training paradigm incrementally introduces stress-inducing components, provides an option for physical movement during fixation, and reward-based training. Most awake animal studies train the animals to tolerate a degree of head/body fixation (4). This study allows the body to freely move with a treadmill module. 3) All trained animal data acquired is included in analysis, to demonstrate variation and homogeneity in training.
Methods:
4 mice (2M/2F, 3-5 mos) were scanned at 9.4T for ZTE fMRI [effective TR=1s; spoke TR=0.891msec; FA=3; BW=129kHz; 407um res; TE=0] 3 times over 2 months. These scans were from an incremental training paradigm, detailed in figure 1a-b. Weight was monitored across the training paradigm, in figure 1c; pupil monitored across scans. During training/scans, mice were initially anesthetized with isoflurane vapor for set-up & cradle positioning. The same treadmill module used in training was directly inserted into the cradle for scanning, in figure 1d. BART reconstruction was followed by motion correction, atlas registration, and temporal filtering. All scans were registered the Allen Atlas (165 key regions: 10 networks). Each registered scan used these key regions and networks to calculate pearson correlation coefficients. Region-level and network-averaged FC matrices are in figure 2.
·Figure 1
Results:
During training, males had an average higher baseline weight than females, though no animal's weight trended downward from baseline. All animals demonstrate decreased motion, including fewer outlying spikes, from scan 1 to scan 2, and scan 2 to scan 3, in figure 1e. FC demonstrates an overall decrease from scan 1 to scan 2 and scan 3, both at an individual level and group average. This may be indicative of less stress, or more likely, an increased level of comfort and familiarity to head fixation and in-scanner environment. Additionally, some granular structure is preserved across all scans.
·Figure 2
Conclusions:
This study provides preliminary results for a robust and reproducible awake mouse fMRI protocol, using ZTE, incremental training, and longitudinal scans. The results indicate initial exposure to the in-scanner environment is useful in mitigating perceived animal stress, evidenced by decreasing head motion from scan 1 to scan 2, and stabilized FC. Despite relatively long latency between scan 2 & 3, FC and motion remain stable. Interpreting high levels of head motion as perceived animal stress, repeated training periods and in-scanner environment exposure does result in a less stressful or learned response to scanning, indicating sufficient training. Including an option for controlled motion in the context of a treadmill belt contributes to this longitudinal decreased stress levels. Future directions include additional refresher training, expanded group sizes, and visual stimulation.
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural)
fMRI Connectivity and Network Modeling 1
Methods Development 2
Novel Imaging Acquisition Methods:
Non-BOLD fMRI
Keywords:
ANIMAL STUDIES
Design and Analysis
FUNCTIONAL MRI
1|2Indicates the priority used for review
Abstract Information
By submitting your proposal, you grant permission for the Organization for Human Brain Mapping (OHBM) to distribute your work in any format, including video, audio print and electronic text through OHBM OnDemand, social media channels, the OHBM website, or other electronic publications and media.
The Open Science Special Interest Group (OSSIG) is introducing a reproducibility challenge for OHBM 2025. This new initiative aims to enhance the reproducibility of scientific results and foster collaborations between labs. Teams will consist of a “source” party and a “reproducing” party, and will be evaluated on the success of their replication, the openness of the source work, and additional deliverables. Click here for more information. Propose your OHBM abstract(s) as source work for future OHBM meetings by selecting one of the following options:
Please indicate below if your study was a "resting state" or "task-activation” study.
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Was this research conducted in the United States?
Are you Internal Review Board (IRB) certified? Please note: Failure to have IRB, if applicable will lead to automatic rejection of abstract.
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.
Please indicate which methods were used in your research:
Which processing packages did you use for your study?
Provide references using APA citation style.
2. Pagani, M., Gutierrez‐Barragan, D., de Guzman, A. E., Xu, T., & Gozzi, A. (2023). Mapping and comparing fMRI connectivity networks across species. Communications Biology, 6(1), 1238.
3. Power, J. D., Schlaggar, B. L., & Petersen, S. E. (2015). Recent progress and outstanding issues in motion correction in resting state fMRI. Neuroimage, 105, 536-551.
4. Mandino, F., Vujic, S., Grandjean, J., & Lake, E. M. (2024). Where do we stand on fMRI in awake mice?. Cerebral cortex, 34(1), bhad478.