Social Media

Yogesh Rathi, Ph.D, Brigham and Women’s Hospital, Harvard Medical School Abstract: MRI data acquired from multiple scanners is affected by several site specific effects such as the vendor specific reconstruction algorithm, the sensitivity of the receiver coils, as well as differences in acquisition parameters. This is especially true for diffusion MRI data. Consequently, direct pooling of data from different scanners can result in dramatically decreased statistical power in detecting subtle changes in the white/gray matter tissue microstructure. Our experimental work shows that these scanner effects are non-linear and vary across different parts of the brain. In this talk, I will present our algorithm on harmonizing dMRI data acquired from multiple scanners for retrospective as well as prospective multi-site studies. In particular, key advantages/disadvantages of this method compared to the standard methods of statistical covariates or meta-analysis will be discussed. I will also talk about our ongoing efforts on harmonizing 30,000 subjects from ABCD, HCP and HBN databases, which will enable very large-scale data analysis using any type of dMRI model. Brief bio: Yogesh Rathi is an Associate Professor at the Brigham and Women’s Hospital, Harvard Medical School. Dr. Rathi’s research interests lie in developing smart imaging techniques to understand brain structure and function. His current research focus is on: 1) Ultra-high resolution diffusion imaging in a clinically feasible scan time combining acquisition and reconstruction; 2) Harmonizing multi-site diffusion MRI data from 30,000 subjects; 3) Estimating tissue microstructure from biophysical and stochastic models of diffusion 4) Time-series analysis for understanding functional connectivity using fMRI data. His clinical research focus includes using and developing sophisticated tractography algorithms for precise targeting of deep-brain stimulation (DBS) and transcranial magnetic stimulation (TMS) in obsessive compulsive disorder (OCD), Parkinson’s and major depressive disorder (MDD). His broad research focus is in the areas of signal and image-processing, statistics, control theory, machine learning, computer vision and related applications to solve inverse problems in medical imaging. Retrospective and Prospective Harmonization of Multi-Site Diffusion MRI Data BrainMap Seminar Series, July 29/2020 For more information about the BrainMap Seminar Series, visit https://www.martinos.org/education/brainmap/ Athinoula A. Martinos Center for Biomedical Imaging https://www.martinos.org/ Follow @MGHMartinos on Facebook, Instagram + Twitter!

Maria Ida Gobbini Medical School of the University of Bologna, Department of Experimental, Diagnostic and Specialty Medicine DIMES Neural Mechanisms for Face Perception and Recognition BrainMap Seminar Series, 07/22/2020 For more information about the BrainMap Seminar Series, visit https://www.martinos.org/education/brainmap/ Athinoula A. Martinos Center for Biomedical Imaging https://www.martinos.org/ Follow @MGHMartinos on Facebook, Instagram + Twitter!

Heidi Johansen-Berg, Ph.D., Director of the Wellcome Centre for Integrative Neuroimaging, FMRIB, University of Oxford Abstract: Animal studies show that the adult brain shows remarkable plasticity in response to learning or recovery from injury. Non-invasive brain imaging techniques can be used to detect systems-level structural and functional plasticity in the human brain. This talk will focus on how brain imaging has allowed us to monitor healthy brains learning new motor skills, to assess how brains recover after damage, such as stroke, and how they adapt to change, such as limb amputation. Although imaging is useful to detect such adaptations, many brain imaging measures are non-specific and do not allow us to pinpoint the underlying cellular changes that are driving observed effects. The talk will also discuss studies in animal models in which both imaging and histological approaches can be used to shed light on the underlying biological drivers for structural plasticity detected using MRI. Finally, the talk will discuss how brain stimulation can be used to manipulate brain remodelling. For example, transcranial direct current stimulation (tDCS) to the motor cortex can speed people¹s learning of a new task, alter their brain chemistry, or improve function in stroke patients. FMRI identifies changes in cortical activity that may mediate these functional benefits. In future, imaging could be used to guide individually targeted brain stimulation to enhance adaptive brain plasticity. Bio: Heidi Johansen-Berg is a Wellcome Principal Research Fellow and Director of the Wellcome Centre for Integrative Neuroimaging (WIN), based at FMRIB at the University of Oxford. The WIN aims to exploit the ability of non-invasive neuroimaging to bridge the gap between laboratory neuroscience and human health. Heidi’s own research group investigates plasticity and recovery in the sensorimotor system, with particular focus on white matter plasticity. The group’s research uses a variety of neuroimaging and stimulation tools in healthy human volunteers across the lifespan, individuals with brain damage, and rodents. Imaging and Stimulating Adaptive Brain Plasticity BrainMap Seminar Series, 07/15/2020 For more information about the BrainMap Seminar Series visit https://www.martinos.org/education/brainmap/ Athinoula A. Martinos Center for Biomedical Imaging https://www.martinos.org/ Follow @MGHMartinos on Facebook, Instagram + Twitter!

Margaret Ormiston, Ph.D. with collaborators Hannah Kremer & Isabel Villamor Martin School of Business, George Washington University Encouraging the success of junior colleagues - Queen Bee Phenomenon Women in Science For more information about the Athinoula A. Martinos Center for Biomedical Imaging Women in Science, visit https://wis.martinos.org/ Athinoula A. Martinos Center for Biomedical Imaging https://www.martinos.org/ Follow @MGHMartinos on Facebook, Instagram + Twitter!

Virginie van Wassenhove, Ph.D., Research Director, Université Paris-Sud, France Abstract: Late 2008, she moved to NeuroSpin (France) to build NeuroSpin MEG and her research group. The Cognition & Brain Dynamics lab mostly uses psychophysics and time-resolved neuroimaging to study temporal cognition, with the understanding, that humans’ conceptualization of time may dramatically affect how we conceive of the mind and brain. The neural mechanisms supporting temporal cognition remain debated considering they do not encompass a unitary brain function. Temporal cognition in humans is a composite of psychological realities ranging from the individuation and ordering of events to the feeling that time passes, that things exist for a while (duration) or that we can mentally travel time. Several difficulties stand in the way of understanding psychological time: subjective temporalities emerge from the perspective of the brain – the generator, actuator and observer of events – and not that of the external observer (the experimenter). The psychological time arrow, taken as our sense of past-to-future, is a convenient metaphor for how allo- and egocentric temporal cognitive maps may help the capacity to mentally travel time, namely the capacity to generate a chronology of events suiting narratives. The ability to introspect about one’s timing productions (temporal metacognition) will further illustrate that time is “represented”, thus coded, and that the variability of timing is also constitutive of temporal representations. Altogether, these recent findings go beyond our classic notions of temporal perception as duration and focus on the endogenous generation of high-level temporalities may yield abstract and intelligible representations of time in the human mind. Bio: Virginie van Wassenhove is a CEA and INSERM Research Director at NeuroSpin, France. She received her PhD in Neurosciences and Cognitive Sciences at the University of Maryland (College Park, USA in 2004). Her thesis proposed the Analysis-by-Synthesis as a generative predictive coding framework for the integration of audiovisual speech in the human brain. In 2005, she joined the UCSF to study auditory and multisensory learning and plasticity with MEG. In 2006, she relocated to a dual position at UCLA and at Caltech to work on multiple projects that included implicit statistical learning, time perception, gesture communication, and interpersonal interactions. Making Sense of Time in the Human Mind BrainMap Seminar Series, 07/08/2020 For more information about the BrainMap Seminar Series visit https://www.martinos.org/education/brainmap/ Athinoula A. Martinos Center for Biomedical Imaging https://www.martinos.org/ Follow @MGHMartinos on Facebook, Instagram + Twitter!