The overall goal of this procedure is to enable localized control over neuroplastic mechanisms in the human brain. Using neurofeedback from real-time functional magnetic resonance imaging. Neurofeedback training holds the potential to combat neurologic disorders of the brain by altering synaptic potentials in target brain regions, without the use of pharmaceutical drugs or invasive surgical intervention.
The main advantage of this technique is that subjects can learn to endogenously alter localized brain activity in a systematic way. The strategies used from altering the localized brain activity can be translated to ubiquitous platforms such as, smart phones, tablets, to enable simple at home solution. Abnormal synaptic potentials in brain connectivity are associated with many neurologic disorders including autism, traumatic brain injury, Parkinson's disease and vestibular disorders.
A feedback is based on chemodynamic changes associated with neuronal activity and thus, has poor temporal resolution, making training more difficult for some subjects. Because hyperactivity of brain regions is often a finding in patients with tinnitus, this approach is aimed at teaching subjects to down regulate activity in regions of interest. Begin by connecting the TR trigger output from the magnetic resonant imaging or MRI machine to the stimulus PC.Then position the MR compatible display so that it will be visible to the participant via the mirror affixed to the head coil.
Next, have the participant lie down in a supine position on the scanner table. Place the headphones on the participant's head and ensure the ears are covered. Then, ask them to keep their head inside the head coil.
Lock the upper body of the head coil into place and affix the mirror to the head coil. Position the response devices in the participant's hands. Next, landmark the location of the participant's nasion relative to the scanner and move the landmark to location to the center of the MRI bore.
Finally, confirm that the participant can view the entire display using the mirror. Begin by providing task instructions to the participant in the MRI room. Then, begin the synchronized administration of audible stimuli and data acquisition by pushing the scan button on the MRI scanner.
Collect whole brain echo planar images using a gradient recall echo MRI pulse sequence. Next, use multi variate statistics to compute an activation map and use the activation map overlaid on a mean fMRI image to determine the region in which the feedback signal for the subsequent neurofeedback will be derived. Then, navigate through the slices using the slice slider bar to find anatomical markers visible in the fMRI data, such as the inferior surface of the frontal horn of the lateral ventricles.
Threshold the activation map using the threshold slider bar, to reveal the box cells most robustly activated during the functional localizer in the target region. Finally, use the left mouse button to select individual voxels with activation above the selected threshold and within the target region to add to the ROI. Begin by instructing the participant to perform mindfulness tasks that drives brain activity towards the desired states.
In the tinnitus example, instruct the participant to divert attention away from the auditory system to either sensory systems to reduce auditory activity. In order to normalize data prior to presenting feedback, instruct the participant to relax during a countdown presented at the beginning of the scan. Then, begin synchronized stimuli presentation and data acquisition by pressing the scan button on the MRI scanner and collect echo planar images in the same manner as the functional localizer scan.
Then visually present a countdown timer and blank feedback display. Next, display the current feedback signal through a thermometer style bar plot where the height of the bar is proportional to the signal measured from the selected box cells. Then, overlay instructions asking the participant to relax, raise or lower the thermometer bar on the feedback display.
Finally, after the neurofeedback session is complete, escort the patient out of the scanner. These results indicated that the control of the left DLPFC increased significantly across five six minute 24 seconds runs of neurofeedback separated across five separate sessions conducted within 14 days. Further, fMRI NFT combined with MBAT practice, creates focal changes in brain activity that are confined to the target region and do not affect up or downstream components of the working memory network.
Once mastered, a single training session using this technique can be completed in as little as 20 minutes. While attempting this procedure, it's important to carefully select the target brain region for neurofeedback. Other methods like diffusion tensor imaging, magnetic resonance spectroscopy, arterial spin labeling and behavioral testing can be performed before or after this procedure to provide additional insight into neuroplastic changes.
After watching this video, you should have a good understanding of how to perform neurofeedback training from real time functional magnetic resonance imaging. Don't forget that the magnetic field associated with MRI can present serious safety issues. Therefore, proper screening should always be performed.
