title: Combining Real-Time fMRI Neurofeedback Training of the DLPFC with N-Back Practice Results in Neuroplastic Effects Confined to the Neurofeedback Target Region.
abstract: In traditional fMRI, individuals respond to exogenous stimuli and are naïve to the effects of the stimuli on their neural activity patterns. Changes arising in the fMRI signal are analyzed post-hoc to elucidate the spatial and temporal activation of brain regions associated with the tasks performed. The advent of real-time fMRI has enabled a new method to systematically alter brain activity across space and time using neurofeedback training (NFT), providing a new tool to study internally-driven processes such as neuroplasticity. In this work, we combined n-back practice with fMRI-NFT of the left dorsolateral prefrontal cortex (DLPFC) to better understand the relationship between open- and closed-loop neuromodulation. FMRI data were acquired during both traditional n-back and NFT across five imaging sessions. Region-of-interest (ROI) and voxel-wise 2 × 2 within subjects ANOVAs were carried out to determine the effects of, and interaction between, training session and neuromodulation type. A main effect of training session was identified for only a single, highly focused cluster that shared spatial properties with the fMRI-NFT target region (left DLPFC). This finding indicates that combined open- and closed-loop neuroplastic enhancement techniques result in focal changes that are confined to the target area of NFT, and do not affect up- or down-stream network components that are normally engaged during working memory. Additionally, we identified a main effect of neuromodulation type for 15 clusters with significantly different activation between open- and closed-loop neuromodulation during training, 12 of which demonstrated higher activity during the open-loop neuromodulation. Our results, taken together with previous reports, indicate that fMRI-NFT combined with n-back practice leads to a highly focal volume exhibiting neuroplasticity without additional network effects.
authors.affiliation: Wright State Research Institute, Wright State UniversityDayton, OH, USA; Department of Biomedical, Industrial, and Human Factors Engineering, Wright State UniversityDayton, OH, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Sherwood
authors.affiliation: Rio Grande Neurosciences Dayton, OH, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Weisend
authors.affiliation: Wright State Research Institute, Wright State UniversityDayton, OH, USA; Department of Neuroscience, Cell Biology, and Physiology, Wright State UniversityDayton, OH, USA.
authors.forename: Jessica H
authors.initials: JH
authors.lastname: Kane
authors.affiliation: Department of Biomedical, Industrial, and Human Factors Engineering, Wright State UniversityDayton, OH, USA; Department of Neurology, Boonshoft School of Medicine, Wright State UniversityDayton, OH, USA.
authors.forename: Jason G
authors.initials: JG
authors.lastname: Parker
keywords: DLPFC; fMRI; n-back; neurofeedback; neuromodulation; plasticity