brain and spinal fMRI

Magnetic resonance imaging (MRI) that is able to demonstrate where the brain is functioning (fMRI) is a relatively new development that has had a significant impact on our understanding of brain function and our ability to detect changes as a result of injury. The focus of research in my lab builds upon important new developments that enable fMRI of the spinal cord and brainstem.  This work will significantly enhance the benefit of fMRI for neuroscience research, and eventually for clinical assessments.  One key advantage of adding spinal cord fMRI to conventional brain fMRI is the ability to study distributed networks, such as related to pain or central sensitization, across the entire CNS from the cord to the cortex.

Current projects are focussed on 1) characterizing the effects of traumatic spinal cord injury, and 2) understanding pain processing.  Both of these projects involve combined brain, brainstem, and spinal cord functional MRI.

Magnetic resonance imaging of neuronal function in the human spinal cord has been developed to the point that it can accurately demonstrate activity in response to a variety of sensory stimuli, painful stimuli, or motor tasks.  It has also been demonstrated to detect changes as a result of traumatic injury and multiple sclerosis. 

Methods have been developed to overcome (or at least reduce) the key challenges of 1) magnetic field differences in different materials (bone, tissue, air),  2) movement caused by the heart beat and breathing, and 3) the small physical dimensions of the spinal cord.

Software has been developed specifically for spinal cord and brainstem fMRI analysis.  This includes methods to reduce image artifacts, correct for movement, carry out the analysis, and convert the results into a spatially normalized form that is the same for every person.  Group analysis to characterize consistent features of how spinal cord and brainstem function are affected by injury, or disease, or normal differences in responses to different sensations can also be carried out.  In addition, software has been developed to carry out analyses to identify connectivity between regions that are working as part of a network.

Example of the most sophisticated connectivity methods that have been applied to the spinal cord and brainstem to date. This figure shows the connectivity between regions in response to two different timing patterns of hot thermal stimulation of the hand. The "block" stimulus is a constant heat at 45 C, whereas the "stepwise" gradually increases in steps to 45 C, and produces a different sensation, with more of the transient response to changes in temperature.   The connectivity was calculated using structural equation modeling (SEM).

This research is supported by: