Journal article
Evaluation of activity-dependent functional pH and T1ρ response in the visual cortex
NeuroImage (Orlando, Fla.), Vol.95, pp.336-343
07/15/2014
DOI: 10.1016/j.neuroimage.2014.01.042
PMID: 24486980
Abstract
Recent experiments suggest that T1 relaxation in the rotating frame (T1ρ) detects localized metabolic changes in the human visual cortex induced by a flashing checkerboard task. Possible sources of the T1ρ signal include pH, glucose, and glutamate concentrations as well as changes in cerebral blood volume. In this study we explored the relationship of the T1ρ signal changes related to cerebral blood volume changes by employing inferior saturation pulses. Our hypothesis was that there would be a contribution of cerebral blood volume to the functional T1ρ signal, but a majority of the signal would correspond to metabolic changes. In addition, the relationship between T1ρ and pH was explored by manipulating the frequency of the flashing checkerboard and imaging with T1ρ, BOLD, and 31P spectroscopy. We hypothesized that T1ρ and pH changes would be sensitive to the stimulation frequency. To test this hypothesis, we used a full-field visual flashing checkerboard and varied the frequency between 1, 4, and 7Hz. Supporting our hypotheses, we found that approximately 73% of the measured signal change corresponds to metabolism in vivo and that increasing stimulation frequency increased responses measured by all three imaging modalities. The activation area detected by T1ρ overlapped to a large degree with that detected by BOLD, although the T1ρ response area was significantly smaller. 31P spectroscopy detected a greater acidosis with the higher stimulation frequencies. These observations suggest that, similar to the BOLD response, the magnitude of the T1ρ and pH response depends on stimulation frequency and is thus likely to be activity-dependent.
•Functional T1ρ imaging shows a faster response as compared to BOLD and ASL imaging.•Functional T1ρ imaging areas of activation overlap significantly with the BOLD.•T1ρ may be a more direct and precise method of imaging brain function.•Functional T1ρ imaging may reflect brain metabolic changes.
Details
- Title: Subtitle
- Evaluation of activity-dependent functional pH and T1ρ response in the visual cortex
- Creators
- Hye-Young Heo - Department of Radiology, University of Iowa, Iowa City, IA 52242, USAJohn Wemmie - Department of Psychiatry, University of Iowa, Iowa City, IA 52242, USADaniel Thedens - Department of Radiology, University of Iowa, Iowa City, IA 52242, USAVincent A Magnotta - Department of Radiology, University of Iowa, Iowa City, IA 52242, USA
- Resource Type
- Journal article
- Publication Details
- NeuroImage (Orlando, Fla.), Vol.95, pp.336-343
- DOI
- 10.1016/j.neuroimage.2014.01.042
- PMID
- 24486980
- NLM abbreviation
- Neuroimage
- ISSN
- 1053-8119
- eISSN
- 1095-9572
- Publisher
- Elsevier Inc
- Grant note
- DOI: 10.13039/100001068, name: DANA Foundation; name: Department of Veterans Affairs (Merit Award); DOI: 10.13039/100000025, name: National Institute of Mental Health, award: 1R01MH085724-01; DOI: 10.13039/100000050, name: National Heart Lung and Blood Institute, award: R01HL113863-01
- Language
- English
- Date published
- 07/15/2014
- 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
- 9984003981702771
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