Welcome Rebecca Clements and Hannah Johnson to the lab!

Hannah Johnson

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

Molly Bright

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

Molly Bright

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.

You can find the open access article here.

Molly joins the Aperture team as Handling Editor

Molly Bright

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.

Two new publications in collaboration with SPiN lab

Molly Bright

Announcing the availability of two new publications in collaboration with the SPiN lab, lead by Cesar Caballero-Gaudes at the Basque Center on Cognition, Brain and Language in Spain! Both focus on the preprocessing and analysis of breath-hold fMRI data to measure cerebrovascular reactivity (CVR) and hemodynamic lag:

BCBL PhD student Stefano Moia and ANVIL postdoc Rachael Stickland co-authored an IEEE paper describing our lagged Generalized Linear Model approach for estimating the temporal delay between systemic carbon dioxide changes and the local BOLD fMRI response, mapping CVR and lag at the voxel level. The approach simultaneously fits other fMRI confounds, such as head motion, to better isolate the physiologic effects of interest. Download the pdf here!

Using the BCBL EuskalIBUR dataset, which uniquely studies breath-hold CVR across 10 repeated weekly MRI sessions, a new preprint in BioRxiv demonstrates the benefits of multi-echo data and compares multi-echo ICA denoising strategies for reliably mapping CVR and lag. Download the pdf here!

CVR maps for an example subject, scanned weekly for 10 weeks. Each row reflects a different use of multi-echo fMRI data, either combining information across the echo times or using the relationship across echo times and Independent Component Analysis (ICA) to differentiate the CVR effects from highly collinear noise confounds.

Research featured at ISMRM Annual Meeting

Molly Bright

Recent work from the lab, lead by first author Dr. Rachael Stickland, was featured in the closing highlights session of the annual meeting of the International Society for Magnetic Resonance in Medicine. The meeting, held virtually for the first time, brought together over 5 thousand clinicians and scientists in the field of MRI and medical imaging for a week of talks, poster presentations, and virtual discussion. Dr. Stickland’s work was selected and discussed by Dr. Kevin Murphy (Cardiff University Brain Research Imaging Center), and demonstrates our lab’s proposed technique for characterizing the responsiveness of brain blood vessels using a simple, feasible, breathing task protocol during scanning. Congrats to all the authors!

Congratulations to Apoorva Ayyagari on completing her Masters Degree!

Molly Bright

The Bright Lab celebrates Apoorva Ayyagari’s completion of her MS degree in Biomedical Engineering at Northwestern! After 2 excellent years as a core member of our lab, Apoorva successfully defended her MS thesis, titled “Understanding noise in spinal cord BOLD fMRI data with a breath-hold paradigm to investigate feasibility of studying vascular reactivity“. In this work, she rigorously assesses cardiac and respiratory noise, motion confounds, and co-linearity between different physiologic signals in spinal cord imaging data. Spinal cord fMRI data are notoriously challenging to work with due to all of these artifactual signals, and this thesis reflects excellent progress in understanding and modeling these factors. Apoorva’s many contributions in the lab will continue to benefit our ongoing projects in mapping cerebrovascular reactivity amplitude and latency, standardizing how physiologic data is collected during MRI scanning, preprocessing spinal cord fMRI data, and quantifying relationships between different sources of signal variance in these data. Although we are extremely sad to see her go, we wish Apoorva the very best as she starts her new job in human factors engineering in Evanston. Congrats Apoorva!

Demonstrating network-level interactions between neural and vascular function

Molly Bright

Our most recent work demonstrating that the brain’s vasculature is regulated to mimic neural networks is now published in Neuroimage: https://doi.org/10.1016/j.neuroimage.2020.116907. This work was performed in collaboration with Prof. Kevin Murphy’s lab at Cardiff University Brain Research Imaging Center in the UK.

Using fMRI, we simultaneously administer two neural paradigms (a working memory task and a visual stimulus) and one “vascular” paradigm that dilates blood vessels systemically (inhaled CO2). We then averaged together 30 fMRI datasets and used Independent Component Analysis to decompose the average dataset into network components. We readily identify three “neural networks” that show strong temporal correlation with the neural stimulus paradigms. These represent the Default Mode Network, Task Positive Network, and Visual Network – three robust and commonly observed functional brain networks expected to be activated or deactivated by our neural paradigms. However, we also see three additional components with similar network structure, and these three networks predominantly reflect the vascular stimulus design.

Our results demonstrate, for the first time, pairs of spatially similar neural and vascular brain networks. This suggests that the brain’s vasculature may be regulated to support specific brain networks, which must be taken into account to interpret fMRI studies of functional connectivity.

Dr. Rachael Stickland receives NUCATS pilot grant

Molly Bright

Congratulations to postdoctoral fellow Dr. Rachael Stickland on her success in the NUCATS Pilot Grant program! Over the coming year, Dr. Stickland will be assessing a multi-parametric imaging protocol focused on cerebrovascular function, testing reliability in healthy participants then translating into patients. This project will use the RespirAct™ to deliver carbon dioxide in a carefully controlled, breath-by-breath basis during concurrent MRI scanning to characterize the associated vasodilatory response. More information about NUCATS can be found on their website.

Funding from the Craig H. Neilsen Foundation to study neural plasticity in Spinal Cord Injury

Molly Bright

The Craig H. Neilsen Foundation has awarded Dr. Molly Bright a SCIRTS Pilot Grant to use imaging to characterize neurovascular plasticity in spinal cord injury. Working with Dr. Milap Sandhu, PT PhD at the Shirley Ryan Ability Lab, we will employ fMRI and cerebrovascular imaging techniques to characterize how one session of Acute Intermittent Hypoxia impacts brain and spinal cord physiology. Acute Intermittent Hypoxia is an emerging intervention that transiently improves motor function in individuals with spinal cord injury; although large clinical trials are getting underway, we aim to better understand the mechanisms for these functional improvements in order to optimize or tailor the intervention. This study will span two years, and recruitment is soon beginning for individuals with incomplete cervical spinal cord injury as well as uninjured control participants. Mark Hoggarth, DPT (left) will be joining the lab later this fall to take the lead on spinal cord imaging and analyses. Welcome Mark, and stay tuned for details on how to get involved with the study!