Associate ProfessorPh.D., McGill University
The Rotman Research Institute Baycrest
3560 Bathurst Street
Toronto, Ontario, Canada M6A 2E1
Phone: (416) 785-2500
Email Dr. Jean Chen
At a Glance
Normal brain function is predicated upon continuous neuronal and vascular interplays, a mechanism that is essential to brain function. It is also likely to deteriorate during the cognitive decline associated with aging as well as neurological disorders. Despite previous research efforts, the causes of aging-related illnesses such as dementia remain unclear, and the key to preventative treatment elusive. My research is driven by the need to better understand disease mechanisms, by using neuroimaging to observe the living brain. My research is focused on functional magnetic resonance imaging (fMRI) methodological development, physiological modeling, and the application of our methods in characterizing diseases/treatments.
As head of the Neuroimaging Lab at Baycrest, Dr. Chen is an Assistant Professor in the Department of Medical Biophysics at the University of Toronto and Scientist at the Rotman Research Institute. She received her MSc (2004) in Electrical Engineering from the University of Calgary, completing her MSc research in contrast-enhanced perfusion MRI with Dr. Richard Frayne. She obtained her PhD (2009) in Biomedical Engineering from McGill University, completing her research at the Montreal Neurological Institute under the supervision of Dr. Bruce Pike. Her PhD research focused on blood-volume measurement and calibrated fMRI. She completed her postdoctoral work on multimodal MRI of brain aging, mentored by Dr. David Salat at the Martinos Center for Biomedical Imaging, affiliated with Massachusetts General Hospital and Harvard Medical School. She was appointed Scientist at the Rotman Research Institute (Baycrest) in 2011. Dr. Chen’s current research revolves around the theme of novel methodological development for the study of brain physiology in aging and age-related brain diseases. Her specific interests include studying the neurovascular and neuronal mechanisms underlying resting-state fMRI, as well as to develop new resting-state brain-mapping techniques for large-scale studies. Her research projects are characterized by the following themes: 1. Investigating the physiological basis of resting-state fMRI; 2. The development of new brain-mapping techniques to map vascular and neuronal health; 3. Multi-modal integration of functional, vascular and structural MRI techniques to study the mechanisms of brain aging and of age-related neurodegenerative diseases.
Demonstration of vascular and physiological effects on resting-state fMRI. We used state-of-the-art ultra-fast fMRI acquisition techniques with multivariate physiological monitoring to assess the effect of carbon dioxide (CO2) fluctuations on the resting-state fMRI signal, providing the first detailed assessment of its kind (Golestani et al., NeuroImage 2014). In addition, we demonstrate experimentally the modulation of fMRI-based functional network measurements by non-neural cerebrovascular reactivity (Golestani et al., NeuroImage 2015).
Demonstration of dynamic neurovascular coupling and vascular bias in resting-state functional MRI. The extent of neurovascular coupling is unknown in resting-state fMRI, much less the effect of vascular contributions to resting-state fMRI functional connectivity. Our work, which used a comprehensive set of vascular measures, demonstrated for the first time the spatial variability in resting-state neurovascular coupling as well as the relationship between functional connectivity measures and macrovascular presence (Tak et al., NeuroImage 2014), with critical implications for rs-fMRI data interpretation (Tak et al., Brain Connect 2015).
Demonstration of dissociation between neurovascular and structural variations in healthy brain aging. Structural changes in the brain have long been observed as part of aging and neurodegenerative diseases. While neuronal integrity is irrevocably tied to neurovascular health, the neurovascular mechanism underlying this structural decline has remained unknown. This work clearly demonstrated, for the first time, distinct patterns of vascular and structural changes in normal aging (Chen et al., NeuroImage 2011), and pioneered a new imaging processing methodology (Chen et al., PLoS ONE 2013) for multi-modality imaging in the community of aging.
Elucidation of the dynamic relationship between vascular and metabolic mechanisms of the BOLD (blood-oxygenation level-dependent) fMRI signal. The understanding of neurovascular interactions in the transient BOLD signal is critical to the understanding and interpretation of BOLD fMRI. For the first time, we obtained simultaneous measurement of BOLD-specific blood flow and volume measurements, which experimentally clarified the origins of the BOLD signal transients (Chen and Pike, NeuroImage 2009). 5. Elucidation of the relationship between vascular and metabolic mechanisms of the BOLD signal. We developed MRI techniques to measure venous cerebral blood volume changes (Chen and Pike, NMR Biomed 2009), which led to the quantification of the venous flow-volume relationship in humans (Chen and Pike, NeuroImage 2010). I also developed methodology to quantify the effect of hypercapnic calibration on cerebral metabolism (Chen and Pike, J Cereb Blood Flow 2010). These measurements are critical for the use of techniques such as calibrated BOLD. The methods associated with these publications have been widely discussed, and the results are being adopted by research labs around the world.
List of Key Publications:Link to Pubmed Publications
Chen JJ, Jann K, Wang DJ. Characterizing Resting-State Brain Function Using Arterial Spin Labeling. Brain Connect. 2015 Oct 6. [Epub ahead of print]
Mark CI, Mazerolle EL, Chen JJ. Metabolic and vascular origins of the BOLD effect: Implications for imaging pathology and resting-state brain function. J Magn Reson Imaging. 2015;42:231-46.
Halani S, Kwinta JB, Golestani AM, Khatamian YB, Chen JJ. Comparing cerebrovascular reactivity measured using BOLD and cerebral blood flow MRI: The effect of basal vascular tension on vasodilatory and vasoconstrictive reactivity. Neuroimage. 2015; 110: 110-123.
Golestani AM, Chang C, Kwinta JB, Khatamian YB, Chen JJ. Mapping the end-tidal CO2 response function in the resting-state BOLD fMRI signal: spatial specificity, test-retest reliability and effect of fMRI sampling rate. Neuroimage. 2015; 104:266-77.
Tak S, Polimeni JR, Wang DJ, Yan L, Chen JJ. Associations of resting-state fMRI functional connectivity with flow-BOLD coupling and regional vasculature. Brain Connect. 2015; 5: 137-146.
Coutu JP, Chen JJ, Rosas HD, Salat DH. Non-Gaussian water diffusion in aging white matter. Neurobiol Aging. 2014;35:1412-21.
Tak S, Wang DJ, Polimeni JR, Yan L, Chen JJ. Dynamic and static contributions of the cerebrovasculature to the resting-state BOLD signal. Neuroimage. 2014; 84:672-80.
Chen JJ, Rosas HD, Salat DH. The relationship between cortical blood flow and sub-cortical white-matter health across the adult age span. PLoS One. 2013;8:e56733.
Chen JJ, Rosas HD, Salat DH. Age-associated reductions in cerebral blood flow are independent from regional atrophy. Neuroimage. 2011;55(2):468-78.
Chen JJ, Pike GB. MRI measurement of the BOLD-specific flow-volume relationship during hypercapnia and hypocapnia in humans. Neuroimage. 2010; 53:383-91.
Chen JJ, Pike GB. Global cerebral oxidative metabolism during hypercapnia and hypocapnia in humans: implications for BOLD fMRI. J Cereb Blood Flow Metab. 2010; 30:1094-9.
Chen JJ, Pike GB. BOLD-specific cerebral blood volume and blood flow changes during neuronal activation in humans. NMR Biomed. 2009; 22:1054-62.
Chen JJ, Pike GB. Origins of the BOLD post-stimulus undershoot. Neuroimage. 2009;46: 559-68.
- Jonathan Kwinta
- Powell Chu
- Don Ragot
- Zahra Faraji-Dana