Posts Tagged functional neuroimaging
[Abstract] Recovery of functional connectivity of the sensorimotor network after surgery for diffuse low-grade gliomas involving the supplementary motor area.
The supplementary motor area (SMA) syndrome is a well-studied lesional model of brain plasticity involving the sensorimotor network. Patients with diffuse low-grade gliomas in the SMA may exhibit this syndrome after resective surgery. They experience a temporary loss of motor function, which completely resolves within 3 months. The authors used functional MRI (fMRI) resting state analysis of the sensorimotor network to investigate large-scale brain plasticity between the immediate postoperative period and 3 months’ follow-up.
Resting state fMRI was performed preoperatively, during the immediate postoperative period, and 3 months postoperatively in 6 patients with diffuse low-grade gliomas who underwent partial surgical excision of the SMA. Correlation analysis within the sensorimotor network was carried out on those 3 time points to study modifications of its functional connectivity.
The results showed a large-scale reorganization of the sensorimotor network. Interhemispheric connectivity was decreased in the postoperative period, and increased again during the recovery process. Connectivity between the lesion side motor area and the contralateral SMA rose to higher values than in the preoperative period. Intrahemispheric connectivity was decreased during the immediate postoperative period and had returned to preoperative values at 3 months after surgery.
These results confirm the findings reported in the existing literature on the plasticity of the SMA, showing large-scale modifications of the sensorimotor network, at both inter- and intrahemispheric levels. They suggest that interhemispheric connectivity might be a correlate of SMA syndrome recovery.
MONDAY, Dec. 2, 2013 (HealthDay News)
Scientists are testing a new thought-controlled device that may one day help people move limbs again after they’ve been paralyzed by a stroke.
The device combines a high-tech brain-computer interface with electrical stimulation of the damaged muscles to help patients relearn how to move frozen limbs.
So far, eight patients who had lost movement in one hand have been through six weeks of therapy with the device. They reported improvements in their ability to complete daily tasks.
“Things like combing their hair and buttoning their shirt,” explained study author Dr. Vivek Prabhakaran, director of functional neuroimaging in radiology at the University of Wisconsin-Madison.
“These are patients who are months and years out from their strokes,” Prabhakaran said. “Early studies suggested that there was no real room for change for these patients, that they had plateaued in the recovery. We’re showing there is still room for change. There is plasticity we can harness.”
To use the new tool, patients wear a cap of electrodes that picks up brain signals. Those signals are decoded by a computer. The computer, in turn, sends tiny jolts of electricity through wires to sticky pads placed on the muscles of a patient’s paralyzed arm. The jolts act like nerve impulses, telling the muscles to move.
A simple video game on the computer screen prompts patients to try to hit a target by moving a ball with their affected arm. Patients practice with the game for about two hours at a time, every other day.
Researchers also scanned the patients’ brains before, during and a month after they finished 15 sessions with the device.
The more patients practiced, the more they were able to train their brains, the researchers found.
The findings were scheduled for presentation Monday at the annual meeting of the Radiological Society of North America, in Chicago.
Strokes occur when blood flow to the brain stops. This happens because a blood clot blocks a blood vessel in the brain or a blood vessel breaks in the brain. Strokes often cause problems with movement and language.