? ? Hemodynamic-based brain-mapping techniques, including functional magnetic resonance imaging (fMRI), are widely used for clinical and basic neuroscience research. However, the exact relationship between neural activity and the hemodynamic response with regard to spatial extent and amplitude is not yet clear. A few studies have examined this issue with the most widely used fMRI technique, which is based on blood oxygenation level dependent (BOLD) image contrast. However, the BOLD effect has a complex mechanism that depends on alterations in cerebral metabolic rate of oxygen (CMR02), cerebral blood flow (CBF), and cerebral blood volume (CBV) in response to increased neuronal activity. More importantly, the spatial specificity of the conventional BOLD signal is hampered by contributions from large draining vessels, which can be a few centimeters from neuronally active sites. Further, BOLD contrast depends on vascular dimensions and geometry, as well as imaging techniques (e.g., gradient-echo, spin-echo) and experimental parameters (e.g., static magnetic field strength, echo time). Thus, a correlation between neural activity and the BOLD effect found in one experimental condition cannot be easily generalized to other conditions. Therefore, we propose to determine (i) the spatial correspondence between neural activity and tissue-specific CBF-based fMRI devoid of large vascular contributions and (ii) the quantitative relationship between neural activity and CBF, which is independent of magnetic field strength and imaging parameters. We will investigate these issues using the well-established cat orientation column model, which has been extensively investigated with single-unit recording, 2-deoxyglucose (2-DG) autoradiography, and optical imaging, and which has already been implemented in the PI's laboratory. Since individual orientation columns are separated by a) 1- 1.4 mm, it is an ideal model for our proposed studies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS044589-02
Application #
6656360
Study Section
Special Emphasis Panel (ZNS1-SRB-R (01))
Program Officer
Babcock, Debra J
Project Start
2002-09-10
Project End
2006-06-30
Budget Start
2003-07-01
Budget End
2004-06-30
Support Year
2
Fiscal Year
2003
Total Cost
$312,940
Indirect Cost
Name
University of Pittsburgh
Department
Biology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Zong, Xiaopeng; Wang, Ping; Kim, Seong-Gi et al. (2014) Sensitivity and source of amine-proton exchange and amide-proton transfer magnetic resonance imaging in cerebral ischemia. Magn Reson Med 71:118-32
Vazquez, Alberto L; Fukuda, Mitsuhiro; Crowley, Justin C et al. (2014) Neural and hemodynamic responses elicited by forelimb- and photo-stimulation in channelrhodopsin-2 mice: insights into the hemodynamic point spread function. Cereb Cortex 24:2908-19
Moon, Chan Hong; Fukuda, Mitsuhiro; Kim, Seong-Gi (2013) Spatiotemporal characteristics and vascular sources of neural-specific and -nonspecific fMRI signals at submillimeter columnar resolution. Neuroimage 64:91-103
Kim, Seong-Gi; Harel, Noam; Jin, Tao et al. (2013) Cerebral blood volume MRI with intravascular superparamagnetic iron oxide nanoparticles. NMR Biomed 26:949-62
Jin, Tao; Kim, Seong-Gi (2013) Characterization of non-hemodynamic functional signal measured by spin-lock fMRI. Neuroimage 78:385-95
Jin, Tao; Wang, Ping; Zong, Xiaopeng et al. (2013) MR imaging of the amide-proton transfer effect and the pH-insensitive nuclear overhauser effect at 9.4 T. Magn Reson Med 69:760-70
Fukuda, Mitsuhiro; Vazquez, Alberto L; Zong, Xiaopeng et al. (2013) Effects of the ??-adrenergic receptor agonist dexmedetomidine on neural, vascular and BOLD fMRI responses in the somatosensory cortex. Eur J Neurosci 37:80-95
Kozai, Takashi D Yoshida; Vazquez, Alberto L; Weaver, Cassandra L et al. (2012) In vivo two-photon microscopy reveals immediate microglial reaction to implantation of microelectrode through extension of processes. J Neural Eng 9:066001
Zong, Xiaopeng; Kim, Tae; Kim, Seong-Gi (2012) Contributions of dynamic venous blood volume versus oxygenation level changes to BOLD fMRI. Neuroimage 60:2238-46
Jin, Tao; Wang, Ping; Zong, Xiaopeng et al. (2012) Magnetic resonance imaging of the Amine-Proton EXchange (APEX) dependent contrast. Neuroimage 59:1218-27

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