Ultrahigh-Field fMRI Findings May Help Patients Recover from Spinal Cord Injury

By MedImaging International staff writers
Posted on 19 Aug 2014

Researchers have achieved the first validated noninvasive measurement of neural signaling in the spinal cords of healthy human volunteers. Their imaging technology may aid efforts to help patients recover from spinal cord injuries and other disorders affecting spinal cord function, including multiple sclerosis.

“We definitely hope that this work can be translated to address many neurological disorders,” said the study’s first author, Robert Barry, PhD, a postdoctoral research fellow in the Vanderbilt University Institute of Imaging Science (VUIIS; Nashville, TN, USA). Directed by senior author John Gore, PhD the study’s findings were published on August 5, 2014, in the journal eLife.

Image: The levels of activity in different parts of the spinal cord of resting individuals were measured using fMRI (Photo courtesy of Barry RL, Smith SA, Dula AN, et al, eLIfe journal, August 5, 2014).

Image: Resting-state signals in the human spinal cord. (A) Horizontal section of a brain (top) and a spinal cord (middle, bottom); the small size of the spinal cord makes it difficult to image neuronal activity. The spinal cord contains two ventral horns (one outlined in red) that are involved in motor function, and two dorsal horns (one outlined in green) that are involved in sensory function. (B) Barry et al. measured the correlation between spontaneous fluctuations in the fMRI signal in the ventral horns (red traces; top) and the dorsal horns (green traces; bottom). This revealed that the ventral horns show a positive correlation with each other, as do the dorsal horns. However, there is no significant correlation between ventral and dorsal horns. This suggests that at rest, the spinal cord is intrinsically organized into two separate networks, corresponding to motor and sensory functions. (C) Possible mechanisms that could explain the spontaneous activity in the spinal cord include input from the peripheral nervous system (top), locally generated rhythms from the interneurons within spinal networks (middle), and ongoing communication between the brain and spinal cord (bottom) (Photo courtesy of Barry RL, Smith SA, Dula AN, et al, eLIfe journal, August 5, 2014).

The researchers used ultrahigh-field functional magnetic resonance imaging (fMRI) to detect for the first time “resting state” signals between neural circuits in the human spinal column. These signals are continuously active, not in response to external stimuli. “We see these background resting circuits as being inherent measures of function,” said Dr. Gore, a professor of medicine, university professor and vice chair of research in the department of radiology and radiological sciences.

The imaging findings may help provide insights into how spinal cord injury alters the “functional connectivity” between neural circuits, for example, and for evaluating and tracking recovery that occurs spontaneously or following various interventions. “The hope is that when you have impaired function that there will be changes [in the signals],” Dr. Gore said. “We’ve already got evidence for that from other studies.”

Research into the “resting” brain reveals how neural circuits coordinate to control various functions and to generate different behaviors. The spinal cord has been more complicated to study because it is much smaller than the brain, and traditional fMRI is not sensitive enough to capture its signals.

The Vanderbilt researchers overcame this hurdle by using an fMRI scanner with a 7 Tesla magnet, multichannel spinal cord coils, and cutting-edge technology for acquiring and analyzing the images.

Related Links:
Vanderbilt University Institute of Imaging Science