Calibration WG Overall goals: 2.Develop and implement means for reducing intersite variations in fMRI sensitivity - Procedures on web site - Paper in press: Friedman & Glover, JMRI 1. Develop and maintain scanner QA methods

Calibration WG Proposed intersite calibration aims: 1. Further develop BH methods (GHG) 2.Develop ASL methods (Tom Liu) 3. Examine smoothing equalization (Friedman et al., in review) 4. Develop new method based on SFNR (Lee Friedman) Bonus Aim

Update on BH Theory and measurements developed Paper on BH kids/adults (Thomason, NI 2005) Paper on BH calib (Thomason, HBM in press) Next steps

Children Working Memory Adults Spatial Verbal M. Thomason low high medium low high medium

BH-induced BOLD signal Vascular res.   HR    CBF  hypoxia Basal metab.  O 2 , CO 2, NO, H +   vasodilation   rCBF Thomason, et. al, NI 2005

Vascular BOLD Uniformity Thomason, et. al, NI 2005

BH Task: Children vs. Adults Thomason, et. al, NI 2005

BH Task: Children vs. Adults Thomason, et. al, NI 2005

BOLD Signal Davis, PNAS (1998) Buxton, 2003 rCBF [HbO2] OEF [Hb] CMRO2 = OEF x rCBF x [HbO2] M. Thomason et al., HBM 2006

BOLD Signal Kastrup (1999) Hoge (1999) BH task F = f BH /f a M. Thomason et al., HBM 2006

Use BH task (non-neuronal, no change in CMRO2) to normalize cognitive task Reduces signal change related to vasoreactivity Should reduce inter-subject variance BH Calibration Method

Adult subjects performed - SWM task (Sternberg) - BH task Compared intersubject variability in WM effect with/without BH calibration WM/BH Study M. Thomason et al., HBM 2006

Raw Calib Calibration: WM M. Thomason et al., HBM 2006

Calibration: WM Raw pixel- wise ROI whole brain 1 Slice for all subjects M. Thomason et al., HBM 2006

Calibration: WM Raw pixel- wise 1 Slice for 3 subjects M. Thomason et al., HBM 2006

No calib BH Calibration: Individual Subs Calib 5 ≤ t ≤ 20 M. Thomason et al., HBM 2006

Calibration: SWM 5 subjects, parietal M. Thomason et al., HBM 2006

No calCalib 3.5 ≤ t ≤ 10 vol = p.001vol = 1.0 BH Calibration: Group Activation M. Thomason et al., HBM 2006

Activation Response M. Thomason et al., HBM 2006 t-score average = 7.82t-score average = No calCalib

Update on BH Theory and measurements developed Paper published on BH kids/adults Paper in press BH calib Next steps

Update on BH Theory and measurements developed Paper published on BH kids/adults Paper in press BH calib Next steps

Variations in inspiration may modulate blood oxygenation Vascular Responsivity: BH Sl 10, aud

Behavioral Effect Mitigation Approaches Model breathing variations using GLM Signal = a * Resp + b * HR

Vascular Responsivity: BH GHG111603

Behavioral Effect Mitigation Approaches Model breathing variations using GLM Signal = a * Resp + b * HR Provide respiration feedback to maintain inspiration level constant

BH Status Program available to make calibrated timeseries- input = timeseries, BH scan, params Developing feedback device piezo electric resp monitor from ADI LED meter, analog electronics. Est. cost $500