OHBM Neurosalience

Maurizio Corbetta is Full Professor and Chair of Neurology in the Department of Neuroscience at the University of Padua, Italy. He is also the founding director of the new Padua Neuroscience Center, a highly interdisciplinary research programme centered on the idea of brain networks in health and society. After receiving is M.D. from the University of Pavia in Italy, he carried out a residency in Neurology at the University of Verona. In 1990 he moved to US, carting out a fellowship in NeuroImaging at Barnes Hospital at Wash U in St. Louis. While in St. Louis, he worked his way up to being the Norman J. Strupp Professor of Neurology, and Professor of Radiology, Anatomy, Neurobiology Bioengineering and Neuroscience at Wash University, as well as Director of Stroke and Brain Injury Rehabilitation at the Rehabilitation Institute of St. Louis. He moved back to Italy, to teh University of Padua, in 2016. Prof. Corbetta has pioneered experiments on the neural mechanisms of human attention using Positron Emission Tomography (PET). He has discovered two brain networks dedicated to attention control, the dorsal and ventral attention networks, and developed a brain model of attention. His clinical work has focused on the physiological correlates of focal injury. He has developed a pathogenetic model of the syndrome of hemispatial neglect. He is currently developing novel methods for studying the functional organization of the brain using functional connectivity MRI, magneto-encephalography (MEG), and electro-corticography (EcoG). He is also working on the effects of focal injuries on the network organization of brain systems with an eye to neuromodulation. He is known for the high level of rigor and deep insight of his research, and has over 16 papers with over 1000 citations. Discussion In our conversation, we discuss some of the key people that influenced him, the incredible team of people at Washington University, as well as some of his early work. We also discuss his perspective on the utility and information in resting state fMRI. He’s senior author of one of the most provocative and compelling explanations for resting state activity that I’ve seen: titled The secret life of predictive brains: what’s spontaneous activity for? Pezzulo et al TICS 2021. We go on from there to discuss his perspective of the substantial importance and profound potential of systems level neuroimaging to not only basic neuroscience but also to clinical practice. Toward the end of our discussion, he highlights how diagnosis and treatment of stroke with neuromodulation can leverage current state of the art neuroimaging techniques.

Guest: Anastasia Yendiki is a faculty member at the MGH Martinos center and a member of the Laboratory for Computational Neuroimaging (LCN).  Her background is in statistical signal and image processing. She received her Ph.D. in Electrical Engineering from the University of Michigan at Ann Arbor, where she worked on inverse problems in tomographic reconstruction for nuclear imaging. As a postdoctoral research fellow at the Martinos Center, Harvard Medical School and Massachusetts General Hospital, she trained in functional and diffusion-weighted MRI. She is responsible for the development of the diffusion MRI analysis tools in FreeSurfer, including TRACULA (TRActs Constrained by UnderLying Anatomy), a diffusion-weighed MRI analysis stream in Bruce Fischl’s FreeSurfer, for automatically reconstructing a set of major white matter pathways from diffusion MRI data using global probabilistic tractography with anatomical priors. She is also interested in ex vivo imaging of human brain circuits with diffusion MRI and optical imaging to both validate and train algorithms for in vivo tractography. Discussion In this wide-reaching discussion we delve into all aspects of her work developing diffusion-based tractography, including her work on better algorithms, current unknowns and challenges, her validation studies, clinical applications, and Connectome scanner at MGH. Towards the end we discuss the planned connectome II scanner and some of the most exciting challenges the field faces.

Denis LeBihan, M.D., Ph.D., is a clinician and physicist, a relentless innovator in the field of MRI and fMRI since the late 80’s, and—as we hear in this podcast—a broad, deep, and highly creative thinker who remains passionate about his work. Denis is the founding director of NeuroSpin in Orsay, France and spends time in Japan as a guest professor at the University of Kyoto and National Institutes of Physical Sciences in Okazaki.   Denis Le Bihan has achieved international recognition for his truly fundamental contributions to the development of diffusion MRI, diffusion tensor imaging (DTI), and the concept of IVIM to image perfusion. It is the b in his name from which the ubiquitous b-factor in diffusion comes from. He has more recently demonstrated the ability to image brain activation-related diffusion coefficient changes. In this podcast, we discuss the intellectual history of Denis’ career. He produced the first diffusion-weighted images, helped establish diffusion tensor imaging, and advanced the concept of imaging perfusion as having an “apparent diffusion coefficient” (ADC) and order of magnitude higher than water diffusion. He has also demonstrated that water diffusion, when imaged with very high b-values, decreases with brain activation. Cell swelling increases the surface area of cells where low diffusion coefficient water resides, thus lowering overall diffusion coefficient. This last result is still debated but generally gaining acceptance with each new paper demonstrating the effect. He also spends some time in the episode talking about his foray into modeling brain function, tapping into inspiration from Einstein and relativity. Overall, it was a fun and inspiring conversation!

In this episode Peter Bandettini speaks with the Chairs of three large neuroimaging societies: Randy Gollub from the Organization for Human Brain Mapping (OHBM), Fernando Calamante from the International Society for Magnetic Resonance in Medicine (ISMRM) and Ron Mangun from the Cognitive Neuroscience Society. Together they consider how COVID-19 has impacted the annual meetings of these societies and some of the innovative strategies used to increase interactivity at online or hybrid meetings.  For more info on the Neurosalience podcast and the guests, visit: www.ohbmbrainmappingblog.com

Dr. Xavier Castellanos is a psychiatrist and a highly influential scientist who has been working in neuroimaging for over 20 years towards the goal of leveraging MRI, fMRI and other approaches to better understand and treat children and adults with psychiatric disorders. Xavier Castellanos studied Chomskian linguistics at Vassar College, experimental psychology at the University of New Orleans, and medicine at Louisiana State University in Shreveport - receiving his M.D. in 1986. He was in the first cohort of “triple board” residents (combined training in pediatrics, psychiatry, and child and adolescent psychiatry) at the University of Kentucky. In 1991, he conducted child psychiatry research at the National Institute of Mental Health under the supervision of Judy Rapaport. In 2001, he moved to New York University, where he is now an endowed Professor of Child & Adolescent Psychiatry and Professor of Radiology and Neuroscience at the NYU Grossman School of Medicine. He has also been a research psychiatrist at the Nathan Kline Institute since 2006, with a focus on using intrinsic functional connectivity-based approaches in human and translational studies. He was an early advocate of using resting state fMRI and of the creation of consortium-driven databases. Dr. Castelanos is one of the most impactful clinical neuroscientists in brain mapping with an h-index of 124 and over 70K citations. He is a highly collaborative and an outstanding mentor, having won the inaugural OHBM Mentor Award last year. Discussion: Here Dr. Castellanos discusses fascinating career development from his early years to his formative decade at the NIH, and finally to his current position at NYU and Nathan Kline. He discusses his embrace of neuroimaging and fMRI towards studying psychiatric disorders and developmental trajectories and expresses a skepticism with the idea that fMRI will reveal clinically useful biomarkers. That said, he emphasizes that fMRI is deeply useful for understanding the organization of the brain in healthy subjects and those with psychiatric disorders.

In this episode Peter Bandettini meets with Drs Lieneke Janssen and Gisela Govaart to discuss grassroots open science projects. They consider how Lieneke & Gisela got started, what is unique about their group (that it is purely student/postdoc driven), what initiatives they are taking on, the need for open science, and how to incentivize people to embrace open science. For more info on the Neurosalience podcast and the guests, visit: www.ohbmbrainmappingblog.com

This is our second episode with Jack Gallant, PhD, a neuroscientist and engineer. Jack is currently a Chancellor’s Professor of Psychology and Class of 1940 Endowed Chair at UC Berkeley and is affiliated with the Department of Electrical Engineering and Computer Science. The first podcast with him delved so deeply into his approach to assessing fMRI data and his philosophy of doing good science and good fMRI that Peter felt they didn’t get a chance to talk about Jack’s groundbreaking results and what questions they open up. In this episode, Peter and Jack discuss his fascinating and potentially paradigm shifting results on widely distributed, semantic maps in the brain that shift and warp depending on the task itself. Peter’s perspective is that these results open up new avenues for insight into fundamentals of brain organization. The brain is not just a conglomeration of distinct and static modules, but a shifting landscape of representation, much of which may be shaped primarily by our experience in the world. How we or our attention shifts these landscapes is an open and potentially profound question.  Peter and Jack also discuss prospects for layer fMRI as well as the challenges of clinical MRI. 

MRI is ultimately about separating a known but variable signal from highly variable noise. How one does this makes all the difference. fMRI is particularly challenging since what is signal and what is noise is not always clear, as they both vary in time and space. In this episode, Peter talks to Jack Gallant, PhD, a neuroscientist and engineer. Jack is currently a Chancellor’s Professor of Psychology and Class of 1940 Endowed Chair at UC Berkeley and is affiliated with the Department of Electrical Engineering and Computer Science. He is a huge proponent of fMRI encoding or, more generally, careful model building to probe the time series. He thinks that more model free approaches and paradigm free methods are ultimately limited. The discussion gets technical as well as intense at times; while Jack and Peter agreed most of the time, there were some nuanced differences of opinion - mostly when it came to discussing alternative methods for probing fMRI data. Overall, we think it was a fun and hopefully a useful discussion!  What comes through is Jack’s passion for what he does. Given that they only barely got started with Peter’s questions, Peter invited him back for another chat - see S2 Episode 6!

Peter talks to Bob Cox, Ph.D., Gang Chen, Ph.D. and Paul Taylor, Ph.D. about AFNI. AFNI is a major processing package used by brain mapping groups all over the world. It is nearly as old as fMRI itself, and has been steadily growing in functionality. Here we discuss the history of how it all started as well as a few of the challenges of fMRI processing that have arisen over the years. Importantly, time is spent discussing more of the philosophy of data analysis and visualization. A key tenet that AFNI has always encouraged is the ability to drill down and look directly at the data. This ability to flexibly and efficiently visualize the data at all processing steps not only guards against problematic data and hidden artifacts but is also a catalyst for new analysis ideas. We discuss a bit of the future of analysis and the bottleneck for clinical implementation. Guests: Bob Cox, Ph.D. is the creator of AFNI and still leads a team, the Scientific and Statistical Core, at the NIH which helps users and continues to develop AFNI. Bob received his Ph.D in Applied Mathematics from Caltech, and after several industry positions and a short stint at Indiana University and Purdue University, he moved to the Medical College of Wisconsin where he began to create AFNI. He moved to the NIH in 2001 where his work accelerated as he was allowed to grow a team of programmers to further advance AFNI. Gang Chen, Ph.D. joined the AFNI team at the NIH in 2003. He is a staff scientist and the chief statistician for things fMRI and related. He received his PhD. from the University of Arizona, Tucson and has been recently pushing our understanding of variability in large N datasets. Paul Taylor, Ph.D. joined the AFNI team in 2015. He received his D. Phil in Astrophysics from Oxford University, and performed post docs at the University of Cape Town and with Bharat Biswal in New Jersey. He has been leading the effort to incorporate diffusion imaging and tractography into AFNI For more info on the Neurosalience podcast and the guests, visit: ohbmbrainmappingblog.com Keywords: #brain #imaging #software #data #fMRI #research #clinical

Peter talks to Dr. Nikola Stikov, a professor of Biomedical Engineering, a researcher at the Montreal Heart Institute, and co-director of NeuroPoly, the Neuroimaging Research Laboratory at Polytechnique Montreal. Nikola is a physicist, engineer and a strong proponent of quantitative and reproducible MRI for further clinical traction and impact. This involves promoting open science, creating shared analysis toolboxes, and fostering data and code sharing across researchers and vendors. As mature as MRI is, we are still just scratching the surface of what information it can provide. Nikola is a gifted and passionate communicator; this conversation touches on his research in using MRI to derive information about cell structure in the brain and the potential uses in understanding brain connectivity as well as pathology. Also discussed is Nikola’s many initiatives regarding open science, dissemination of results, publishing - and how outdated the pdf is, and science outreach. For more info on the Neurosalience podcast and the guests, visit: ohbmbrainmappingblog.com