Journal article
Eccentricity mapping of the human visual cortex to evaluate temporal dynamics of functional T1ρ mapping
Journal of cerebral blood flow and metabolism, Vol.35(7), pp.1213-1219
07/2015
DOI: 10.1038/jcbfm.2015.94
PMCID: PMC4640285
PMID: 25966957
Abstract
Recent experiments suggest that T1 relaxation in the rotating frame (T(1ρ)) is sensitive to metabolism and can detect localized activity-dependent changes in the human visual cortex. Current functional magnetic resonance imaging (fMRI) methods have poor temporal resolution due to delays in the hemodynamic response resulting from neurovascular coupling. Because T(1ρ) is sensitive to factors that can be derived from tissue metabolism, such as pH and glucose concentration via proton exchange, we hypothesized that activity-evoked T(1ρ) changes in visual cortex may occur before the hemodynamic response measured by blood oxygenation level-dependent (BOLD) and arterial spin labeling (ASL) contrast. To test this hypothesis, functional imaging was performed using T(1ρ), BOLD, and ASL in human participants viewing an expanding ring stimulus. We calculated eccentricity phase maps across the occipital cortex for each functional signal and compared the temporal dynamics of T(1ρ) versus BOLD and ASL. The results suggest that T(1ρ) changes precede changes in the two blood flow-dependent measures. These observations indicate that T(1ρ) detects a signal distinct from traditional fMRI contrast methods. In addition, these findings support previous evidence that T(1ρ) is sensitive to factors other than blood flow, volume, or oxygenation. Furthermore, they suggest that tissue metabolism may be driving activity-evoked T(1ρ) changes.
Details
- Title: Subtitle
- Eccentricity mapping of the human visual cortex to evaluate temporal dynamics of functional T1ρ mapping
- Creators
- Hye-Young Heo - 1] Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USAJohn A Wemmie - 1] Department of Psychiatry, University of Iowa, Iowa City, Iowa, USA Department of Neurosurgery, University of Iowa, Iowa City, Iowa, USA Department of Veterans Affairs Medical Center, Iowa City, USACasey P Johnson - Department of Radiology, University of Iowa, Iowa City, Iowa, USADaniel R Thedens - Department of Radiology, University of Iowa, Iowa City, Iowa, USAVincent A Magnotta - 1] Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA Department of Psychiatry, University of Iowa, Iowa City, Iowa, USA
- Resource Type
- Journal article
- Publication Details
- Journal of cerebral blood flow and metabolism, Vol.35(7), pp.1213-1219
- DOI
- 10.1038/jcbfm.2015.94
- PMID
- 25966957
- PMCID
- PMC4640285
- NLM abbreviation
- J Cereb Blood Flow Metab
- ISSN
- 0271-678X
- eISSN
- 1559-7016
- Publisher
- United States
- Grant note
- R01 MH085724 / NIMH NIH HHS U54 TR001356 / NCATS NIH HHS R01 HL113863 / NHLBI NIH HHS R01HL113863-01 / NHLBI NIH HHS U54 TR001013 / NCATS NIH HHS 1R01MH085724-01 / NIMH NIH HHS U54TR001013 / NCATS NIH HHS
- Language
- English
- Date published
- 07/2015
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Electrical and Computer Engineering; Molecular Physiology and Biophysics; Psychiatry; Iowa Neuroscience Institute; Neurosurgery
- Record Identifier
- 9984003469702771
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