Neuroscience 2003 Abstract
| Presentation Number: | 692.8 |
|---|---|
| Abstract Title: | Measurement of CMRO2 in barrel cortex using MRI, LDF, and OIS. |
| Authors: |
Mayhew, J. E.*1
; Kennerley, A. J.1
; Berwick, J.1
; Martindale, J.1
; Papadakis, N.1
1Dept. Psychol, Univ. Scheffield, Sheffield, United Kingdom |
| Primary Theme and Topics |
Sensory Systems - Tactile/Somatosensory -- Cortex imaging |
| Session: |
692. Cortical Imaging: Methodology Poster |
| Presentation Time: | Tuesday, November 11, 2003 4:00 PM-5:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # E6 |
| Keywords: | FMRI, OPTICAL IMAGING, BLOOD FLOW, BARREL |
Optical imaging spectroscopy (OIS), laser Doppler flowmetry (LDF) and magnetic resonance imaging (MRI) were used to investigate the hemodynamic response to neural activation in rat barrel cortex. The MRI measurements were made at 3T in a small animal magnet facility (Magnex with MRRS console). Both fMRI measurements of the BOLD signal and cbv-MRI estimates of changes in blood volume (CBV) were obtained concurrently with measurements of CBF using a magnet compatible LDF probe (Perimed) following both electrical stimulation of the whisker pad (16s,1.2mA @5Hz) and hypercapnic challenge (120s @10% CO2).
MRI measurements were obtained using a GRE-EPI sequence at a voxel resolution of 470x470x2000µm. Of necessity, cbv-MRI data was collected after BOLD measurements following infusion of the contrast agent AMI-227 (10mgFe/kg ~200µmol Fe/kg).
The BOLD and cbv-MRI data from the hypercapnic challenges were used to estimate the baseline scaling term M=TE.A.CBV0.[Hbr]βv0 used in the biophysical model of the BOLD signal under activation (Davis 1998). Changes in CMRO2 were calculated by transforming the cbv-MRI measurements into estimates of changes in CBF using the relationship established by Grubb (1974): CBF= CBV2.63. These results are compared with estimates of CMRO2 changes more directly calculated using the LDF measurements of flow changes and with changes estimated from optical imaging spectroscopy and the OTT biophysical model (Zheng et al. 2002). The relationship found between the fractional changes in CBV determined by cbv-MRI, optical-imaging spectroscopy (Hbt) and those in CBF measured by LDF for both the hypercapnia and activation data were not significantly different from the value of Grubb’s exponent.
MRI measurements were obtained using a GRE-EPI sequence at a voxel resolution of 470x470x2000µm. Of necessity, cbv-MRI data was collected after BOLD measurements following infusion of the contrast agent AMI-227 (10mgFe/kg ~200µmol Fe/kg).
The BOLD and cbv-MRI data from the hypercapnic challenges were used to estimate the baseline scaling term M=TE.A.CBV0.[Hbr]βv0 used in the biophysical model of the BOLD signal under activation (Davis 1998). Changes in CMRO2 were calculated by transforming the cbv-MRI measurements into estimates of changes in CBF using the relationship established by Grubb (1974): CBF= CBV2.63. These results are compared with estimates of CMRO2 changes more directly calculated using the LDF measurements of flow changes and with changes estimated from optical imaging spectroscopy and the OTT biophysical model (Zheng et al. 2002). The relationship found between the fractional changes in CBV determined by cbv-MRI, optical-imaging spectroscopy (Hbt) and those in CBF measured by LDF for both the hypercapnia and activation data were not significantly different from the value of Grubb’s exponent.
Supported by NIH/NINDS Grant 5R01NS044567, MRC Grant No. 54030: G0100538:
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
Copyright © 2003-2026 Society for Neuroscience; all rights reserved. Permission to republish any abstract or part of any abstract in any form must be obtained in writing by SfN office prior to publication.
