Abstract #4129
            Characterization and Reduction of Cardiac- and Respiratory- Induced Noise as a Function of the Sampling Rate (TR) in fMRI
                      Dietmar Cordes                     1,2                    , Rajesh R. Nandy                     3                    , 						Scott Schafer                     2                    , and Tor D. Wager                     2          
            
            1
           
           Ryerson University, Toronto, Ontario, 
						Canada,
           
            2
           
           University 
						of Colorado, Boulder, Colorado, United States,
           
            3
           
           University 
						of North Texas Health Science Center, Texas, United 
						States
          
            
          The physiological noise in the lower brain areas (brain 
						stem and nearby regions) are investigated in 
						resting-state data and a novel method is presented for 
						computing both low-frequency and high-frequency 
						physiological regressors. In particular, using a novel 
						optimization algorithm that penalizes curvature, the 
						cardiac -and respiratory-related low-frequency response 
						functions are computed. Also, the frequency-aliasing 
						property of the high-frequency cardiac waveform as a 
						function of the repetition time (TR) is investigated. It 
						is shown that for brain areas associated with large 
						pulsations of the cardiac rate, the temporal SNR 
						associated with the BOLD response has maxima at 
						subject-specific TRs.
         
				
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