Effects of Timing and Duration of Cognitive Activation in [15O]Water PET Studies
Open Access
- 1 May 1994
- journal article
- Published by SAGE Publications in Journal of Cerebral Blood Flow & Metabolism
- Vol. 14 (3), 423-430
- https://doi.org/10.1038/jcbfm.1994.53
Abstract
The multiple injection [15O]water method offers unique opportunities for studying cognitive processing by the human brain. The influence of the duration and temporal placement of an activation task, in relation to the arrival of the radiotracer in the brain, is a fundamental methodologic question for cognitive activation studies. A quantitative positron emission tomography (PET) study of five normal volunteers was performed in which the stimulation consisted of a visual activation task (alternating checkerboard pattern) superimposed on an auditory baseline task (syllable monitoring). Ten injection conditions, with varying duration and timing of the visual activation, were used. Regional CBF (rCBF) in visual cortex was measured quantitatively using the autoradiographic method. A 20-s stimulation, centered on the bolus arrival in the brain, produced significant changes in rCBF. Because varying the duration and timing of the activation task technically violates the temporal homogeneity assumption of the autoradiographic model, a mathematical simulation was formulated to evaluate the potential influence of these variations. Results of the simulation are consistent with the PET data and suggest that activation can be limited to a narrow temporal window centered on the radiotracer uptake. The ability to observe significant changes in rCBF with short stimulation intervals is of particular interest in the use of [15O]water PET for studies of cognitive processes with a short time course.Keywords
This publication has 19 references indexed in Scilit:
- Improved Detection of Focal Cerebral Blood Flow Changes Using Three-Dimensional Positron Emission TomographyJournal of Cerebral Blood Flow & Metabolism, 1993
- Voxel processing techniques for the antemortem study of neuroanatomy and neuropathology using magnetic resonance imagingThe Journal of Neuropsychiatry and Clinical Neurosciences, 1993
- The Comprehensive Assessment of Symptoms and History (CASH)Archives of General Psychiatry, 1992
- Image processing for the study of brain structure and function: problems and programsThe Journal of Neuropsychiatry and Clinical Neurosciences, 1992
- Comparing Functional (PET) Images: The Assessment of Significant ChangeJournal of Cerebral Blood Flow & Metabolism, 1991
- Enhanced Detection of Focal Brain Responses Using Intersubject Averaging and Change-Distribution Analysis of Subtracted PET ImagesJournal of Cerebral Blood Flow & Metabolism, 1988
- Mapping human visual cortex with positron emission tomographyNature, 1986
- Stimulus rate dependence of regional cerebral blood flow in human striate cortex, demonstrated by positron emission tomographyJournal of Neurophysiology, 1984
- On the Uniqueness of Cerebral Blood Flow Measured by the in vivo Autoradiographic Strategy and Positron Emission TomographyJournal of Cerebral Blood Flow & Metabolism, 1983
- A Simplified in vivo Autoradiographic Strategy for the Determination of Regional Cerebral Blood Flow by Positron Emission Tomography: Theoretical Considerations and Validation Studies in the RatJournal of Cerebral Blood Flow & Metabolism, 1982