Hand-grasping is an important and clinically significant daily function, but more work is needed to understand the associated spinal cord neural activity. In this study, participants performed a hand-grasping task with both hands and spinal cord fMRI motor activation was modeled with two methods: (1) a typical idealized block design (Ideal) and (2) based on recorded grasp force normalized to individual maximum voluntary contraction (%MVC). Robust detection of hand-grasping activity was shown in the spinal cord, highly lateralized ipsilateral to the side of the task. In addition, the impact of sample size, number of fMRI runs, and spatial smoothing on activation estimates was explored. Overall, we emphasize the importance of a task that is well-controlled within and across participants. Using individually calibrated tasks in people with motor impairments will be especially beneficial to compare across groups.If you want to learn more, please check out the paper here!
Announcements
Multiple ANVIL successes to celebrate!
Congratulations are in order for three outstanding accomplishments from ANVIL lab members this past month!
Becca Clements (2nd year PhD student in BME) was awarded a 3-year fellowship from the NSF Graduate Research Fellowship Program! This will fund her exploration into the organization of vascular regulation in the human brain, and particularly the presence of long-distance “vascular networks” that may support typical functional neural networks.
Kim Hemmerling (4th year PhD student in BME) received a stellar 6%ile score on her NIH F31 Predoctoral Fellowship application! This score reflects the amazing potential for the spinal cord fMRI methods she has been developing in our lab, and specifically towards looking at atypical upper limb movement patterns post-stroke.
And finally, Max Wang (Postbac Research Technologist) has been awarded a prestigious Fulbright Scholarship! Max will pursue his Masters research in translational neuroimaging at the University of Nottingham in the UK starting this fall.
These successes reflect the impressive ongoing hard work and perseverance of our trainee researchers. We are so pleased to see these efforts acknowledged and rewarded, and we are looking forward to seeing what new science emerges as they begin these exciting projects. Congratulations Becca, Kim, and Max!
Exploring variability in spinal cord fMRI processing
How reliable are our current techniques for processing spinal cord fMRI data? In a recently published paper, Dr. Mark Hoggarth and Max Wang explore how person-to-person variability in the contouring of fMRI spinal cord masks affects downstream analyses. Using masks drawn by 8 raters of varying experience to inform co-registration to standard template space, they identify spatial differences in the accuracy of registration related to underlying image contrast and rater experience. At the group-level, spatial differences were present in activation maps although no systematic effect on overall activation level was identified. This work characterizes how variability in manually contoured masks propagates to results in spinal cord fMRI, demonstrating that standardization of processing pipelines and improving image acquisition should be prioritized.
This work was performed in collaboration with Dr. Kenneth Weber at the Stanford Systems Neuroscience and Pain Lab.
You can find the full access paper here!
New paper on the correlation between baseline blood flow and vascular reactivity in the brain
A recent paper from the lab, led by Dr. Rachael Stickland, identifies a positive correlation between baseline cerebral blood flow (CBF) and Blood Oxygenation Level Dependent cerebrovascular reactivity (BOLD-CVR), measured with MRI. This positive correlation is seen between and within subjects and is strengthened by the addition of a breathing task to a resting-state acquisition and by optimizing for hemodynamic lag effects in CVR modeling. This work demonstrates how two analytical factors affect the observed relationship 
between baseline CBF and BOLD-CVR in healthy populations; the relationship becomes even more relevant to understand when interpreting results in
populations with altered vascular baselines or impaired cerebrovascular reserve.
This work was performed in collaboration with Dr. César Caballero-Gaudes’ lab at the Basque Center on Cognition, Brain and Language in Spain.
Check out the paper here!
Conference paper on visualization tool for assessment of spinal cord fMRI data quality
Check out our conference paper that was presented at the IEEE Engineering in Medicine and Biology Conference and published online in December 2021! This paper details our method, developed by PhD candidate Kimberly Hemmerling, for visualization of complex spinal cord fMRI data as heatmaps. This work was inspired by a visualization technique designed for brain fMRI data (Power et al., 2017). Our heatmaps can be visualized alongside motion or physiological traces that may be used to identify coincidence of signal variation. The technique may be easily integrated into a preprocessing pipeline to visualize the effect of a preprocessing step, identify spatially or temporally varying artifacts, or to assess general data quality.Check out the work here, and our GitHub repository (BrightLab-ANVIL/spinalcordplot), which contains the code and example data necessary to generate the plots.
Lab awarded NIH funding for clinical trial to enhance brain blood flow
Molly has been awarded a two-year R21 grant from NINDS to determine the ability of Acute Intermittent Hypoxia therapy to enhance blood flow in the brain of healthy adults. This controlled cross-over trial is an exploratory “high-risk, high-reward” study that examines whether a simple intervention can increase resting cerebral perfusion and the vasodilatory responsiveness of cerebral blood vessels. The intervention is already used in several studies at Northwestern University and the Shirley Ryan AbilityLab to evoke neural plasticity for rehabilitation, and this study explores whether it also achieves vascular plasticity. Participants will undergo three weeks of regular, brief exposures to hypoxia, and advanced arterial spin labeling MRI techniques and MRI-compatible gas challenges will be used to assess the impact on the cerebrovasculature. Recruitment starting soon; see the Current Studies page for more information!
Welcome Rebecca Clements and Hannah Johnson to the lab!
ANVIL welcomes two new Biomedical Engineering students to the lab!
From left to right: Hannah and Becca join Neha, Kristina, and Kim as ANVIL BME doctoral students
Rebecca Clements is a new PhD student coming to us from the University of Delaware, where she completed her Bachelors degree in Biomedical Engineering. She has extensive research experience working in the Mechanical Neuroimaging lab at UD, where she used magnetic resonance elastography measures to better understand age-related changes to the brain.
Hannah Johnson, also an incoming PhD student, joins us from the University of Arizona, where she earned her Bachelors degree in Biomedical Engineering. As an undergraduate, she worked with Dr. Elizabeth Hutchinson in the Multi-Scale Brain Imaging Lab to identify longitudinal biomarkers of traumatic brain injury in preclinical models using MRI.
Becca and Hannah are excited to be joining the team, and we look forward to working with them!
A new strategy for adding vascular insight to resting state fMRI
Congratulations to postdoctoral research fellow Rachael Stickland and colleagues on our publication in Neuroimage, titled A practical modification to a resting state fMRI protocol for improved characterization of cerebrovascular function.
By simply adding a few short breath-holds or deep breaths to the start of a typical resting state fMRI acquisition, we can achieve much more robust maps of cerebrovascular reactivity (CVR, the dilatory responsiveness of blood vessels) as well as the temporal delay of this response. We show that this practical approach can identify atypical cerebrovascular function, and that it is essential to understand both the amplitude and timing of the vascular response to accurately characterize pathology. This approach is easy to incorporate into traditional fMRI experiments and could help determine how vascular function and neural function are related in disease.
Find the (open access) full paper here!
New review paper on mapping CVR without gas challenges
Check out our latest publication in Frontiers Physiology, titled “Cerebrovascular Reactivity Mapping Without Gas Challenges: A Methodological Guide”. This work was lead by the excellent Joana Pinto, now a postdoc in Oxford, and covers breathing task methodology and resting state approaches for measuring CVR. This article is part of a special Frontiers “research topic” on Imaging CVR: Physiology, Physics, and Therapy.
Molly joins the Aperture team as Handling Editor
We are excited to announce that Aperture, the new online journal affiliated with the Organization for Human Brain Mapping, has just opened for submissions, and Molly has been invited to act as a founding Handling Editor for this exciting new format for scientific publishing. Aperture is an open-access, peer-reviewed, online journal created by members of OHBM to share and promote research beyond the traditional PDF, looking for research that will enhance, innovate, and advance neuroscience. We will publish traditional articles (research reports and reviews) but also other “research objects”, including tutorials, workshops, processing pipelines, software, simulations, computational notebooks, and datasets. For more details on the journal, submission process, and the editorial team, check out the new Aperture website.