Tingying Peng1, Rami Niazy2, Richard Wise, Stephen Payne3
1Institute of Biomedical Engineering, University of Oxford, Oxford, Oxfordshire, UK; 2CUBRIC, University of Cardiff, Cardiff, UK; 3Institute of Biomedical Engineering, University of Oxford, Oxford, UK
Spontaneous fluctuations in arterial carbon dioxide (CO2) have previously been identified as an important source of low frequency variations in the resting-state BOLD signal. Current study investigates the underlying relationship between CO2 and BOLD variations under two circumstances: eyeopen and eyeshut by using linear regression analysis and cross-correlation analysis. It has been found out that the time delay between the two signals is significantly shorter in eyeshut than in eyeopen. Furthermore, wavelet cross-correlation analysis is used to investigate the frequency-dependency of the CO2-BOLD coupling, suggesting the effects of CO2 are concentrated in the low frequency band 0-0.08Hz.