In our week-end roundup of neuroscience news covering various developments in brain science, we look at electrical spinal cord stimulation, deconstructing behavioral neuropharmacology, and other areas.
Earlier in the week, Mayo Clinic researchers reported they used electrical stimulation on the spinal cord and intense physical therapy to help a man intentionally move his paralyzed legs, stand and make steplike motions for the first time in three years.
The patient underwent surgery to implant an electrode in the epidural space near the spinal cord below the injured area. The electrode is connected to a computer-controlled device under the skin in the patient’s abdomen. This device, for which Mayo Clinic received permission from the U.S. Food and Drug Administration for off-label use, sends electrical current to the spinal cord, enabling the patient to create movement. (Peter J. Grahn et al. Enabling Task-Specific Volitional Motor Functions via Spinal Cord Neuromodulation in a Human With Paraplegia, Mayo Clinic Proceedings)
Deconstructing Behavioral Neuropharmacology
Researchers at Duke University and the Howard Hughes Medical Institute have developed a way to deliver drugs to specific types of neurons in the brain.
The approach could eventually provide a platform whereby the mechanism of action for widely psychiatric prescribed drugs can be examined with cellular specificity in animal models of several disorders. Such studies could inform new translational strategies by advancing non-obvious drug combinations. (New Method Targets Neuropsychiatric Drugs To Genetically Specified Cells)
Deep Brain Stimulation Decreases Tourette Tics
In more neurostimulation news, thalamic deep brain stimulation, a surgical technique that sends electrical impulses to a specific area of the brain, reduces the “tics” experienced by young adults with severe cases of Tourette syndrome, according to a new study from NYU Langone Medical Center published April 7 in the Journal of Neurosurgery.
The deep brain stimulation involves a multi-stage procedure. First, two electrodes are inserted the medial thalamus, part of the brain circuit that functions abnormally in Tourette’s. During a second surgery the following day or a few days later, a pacemaker-like device called a neurostimulator is connected to the electrodes to emit electrical impulses into the medial thalamus. These impulses are adjusted during a series of follow-up outpatient visits to find the combination of settings that best control symptoms.
To determine the effectiveness of the procedure, the researchers measured the severity of tics before and after surgery in 13 patients. They found that the severity of tics decreased on average 37 percent from the time of the operations to the first follow-up visit. At their latest visit, patients' tic scores decreased by an average of 50 percent.
University of Michigan researchers used PET scans of the brain in a small study to demonstrate that dopamine falls and fluctuates at different times during migraine headaches. During an attack, the 8 migraine patients' studied showed dopamine levels that fell significantly, they found.
Migraine was also the subject of focus in a study from researchers at the University of Toronto who found that generalized anxiety disorder is much more common among adults who have migraines than those without migraine.
An earlier study in 2008 made a link between social anxiety disorder and altered dopamine uptake activity in the striatum. Another 2008 study in Nature Neuroscience linked anxiety, emotional processing in the amygdala, and dopamine storage capacity.
Interestingly, the University of Michigan study found that men with migraine had almost double the odds of generalized anxiety disorder compared with women with migraine.
“This was a surprising finding because in the general population, women are more likely than men to develop generalized anxiety disorder. Our results may be due to the fact that men are less likely than women to take medication to treat their migraine and therefore the disorder may be more painful and less controllable, which could result in anxiety”
said co-author Senyo Agbeyaka, a recently graduated MSW student.
What’s more, migraineurs who did not have a confidant had five times the odds of generalized anxiety disorder compared to those with at least one person to confide in; with social support being shown to play an important protective role in the mental health consequences of other chronic pain disorders.
Elsewhere, researchers warned regulators of the need to monitor and control the use of ketamine for the treatment of depression. In the study, published in Lancet Psychiatry, Oxford University specialists said patients' treatment should be in specialist centers and formally tracked in national or international registries. Johnson & Johnson is currently developing an intranasal form of the drug, esketamine. Early results have been promising enough for Food and Drug Administration officials to award esketamine breakthrough status to speed its progress through regulatory hurdles.
Image: Mayo Clinic