ORGANIZERS: Jennifer A. McNab, Ph.D. & Joshua S. Shimony, M.D., Ph.D.
Saturday, 22 April 2017
||13:15 - 17:45
||Moderators: Andrada Ianus, Elizabeth Meyerand
Skill Level: Advanced
Slack Channel: #e_diff_perf_fmri
Session Number: WE06
This session will highlight a variety of different methods that can be used to measure structural or functional brain connectivity including diffusion tractography, RS-FMRI and complementary non-MRI approaches such as optical imaging, Ecog, electrophysiology and histology.
This course is designed for basic scientists, clinicians and technologists, who would like to learn more about MRI connectivity measurements.
Upon completion of this course, participants should be able to:
-Plan experiments for structural and functional connectivity MRI measurements;
-Conduct correlation analyses with connectomics measurements; and
-Distinguish between the different types of connectivity information provided by RS-FMRI, Diffusion MRI, Ecog, Electrophysiology and Histology.
In this talk I will outline basic approaches for charting the organisation of functional connectivity and introduce novel tools and techniques that enable characterisation of functional connectors in terms gradual change in connectivity profiles. I will provide examples of how these techniques can be used in clinical and cognitive neuroscience research.
|Measuring Connectivity with RSFMRI
Connectivity in resting-state fMRI can be evaluated through a variety of different methods. These include methods for static functional connectivity, such as seed-correlation, spatial independent component analysis, and graph theoretical approaches. In addition, dynamic functional connectivity can be assessed using methods such as sliding window correlation, time-frequency analysis, co-activation patterns and temporal independence component analysis.
|Measuring Connectivity with Diffusion MRI
I will present the pipeline that is used for computing estimates of structural brain connectivity as obtained with diffusion tractography. Several methodological considerations will be discussed.
|What Correlates with Your Connectome?
Since the introduction of functional and structural connectivity approaches, MRI has been used to assess age-related differences on a brain network level. A systems-level or network approach of brain structure and function provides an intuitive framework for understanding a complex dynamic system. In this talk I will discuss previous research that used MRI to study the effect of aging on brain networks in vivo, through functional connectivity measures derived from resting-state functional MRI and structural connectivity measures derived from diffusion MRI.
|Break & Meet the Teachers
|RSFMRI - correlation with optical imaging in neonates
Diffuse optical imaging (DOI) is a portable imaging modality that provides the ability to perform early and continuous monitoring of brain function. Its portability overcomes many of the technical and logistical challenges of performing MRI investigations in hospitalized patients. While standard DOI systems suffer from low spatial resolution and lack of brain specificity, new developments in hardware and software have overcome many of these technical limitations. In this talk, I will introduce novel DOI techniques developed for bedside mapping of resting-state functional connectivity in neonates and adults and present multi-modal comparisons with functional MRI maps obtained in the same subjects.
|FMRI - Ecog Correlates
Carl Hacker, Abraham Snyder, Mrinal Pahwa, Maurizio Corbetta, Eric Leuthardt
This talk will focus on recent developments in studying the electrophysiologic basis of functional MRI correlations. We will examine methods to measure the spatial correspondence between electrophysiologic band-limited power (BLP) and fMRI correlation patterns in human subjects. We will then discuss the available evidence that correlated, spontaneous activity of the brain exhibits frequency specificity, and outline a hypothesis that the spectral structure of task responses is reflected in the hierarchical organization of RSNs.
|Diffusion - Histology Correlates
MRI parcellation and connectivity is widely used in neuroscience, however their validation have been challenging. In this talk, sevreral validation methods will be discussed, such as histology, polarized light imaging and optical coherence tomography.
|Diffusion - Electrophysiology Correlates
Bernard Siow, Simon Richardson
The majority of fMRI studies use T2 or T2* weighted scans. Studies have shown that diffusion MRI scans can detect activation. However, the exact biophysical mechanism remains unclear. We will explore the physiology of neuronal activation, the BOLD response, fMRI and diffusion MRI, and how to disentangle the BOLD response and microstructure changes.