Spinal cord fMRI: functional response and linear model assessment

a a a Introduction Functional magnetic resonance imaging (fMRI) has emerged during the last decade as the main non-invasive technique for the investigation of human brain function. More recently some studies have been conducted also to reveal the activation in the human spinal cord [1-2], albeit the characteristics of functional contrast are still debated [3] (even its BOLD origin has been challenged). Although performing fast imaging in the spinal cord still remains a technical challenge (motion-effects and susceptibility artifacts, related to local inhomogeneities, do impair the quality and the spatial resolution of the images), such kind of investigation provides promising perspectives for the study and follow-up of spinal cord injuries. In this study we report the results obtained applying an fMRI block-design motor paradigm of the upper limb to identify the hemodynamic response function (HRF, i.e. the impulse response function) in the human cervical spinal cord and to test the linearity assumption of fMRI response.