Objectives: The present study tested whether functional and structural neuroanatomical changes occur after 20 weeks of mu-based neurofeedback training.
Methods: Neurofeedback training is an operant conditioning task in which trainees learn to control mu rhythm (8-13 Hz) power at electrode site C4, over the sensorimotor cortex in the right hemisphere. Games and movies on a computer reward increased mu-power and decreased muscle activity. All participants complete 30 hours of this training (45 min/session x 2 sessions/week x 20 weeks). Prior to and again immediately following training, participants (7 ASD and 8 TD, ages 8-17) underwent fMRI scans that included the following protocols: resting state fMRI (6 min), 3 fMRI runs of a task that involved imitation and observation of object-oriented finger movements (total of 15 min), anatomical (5 min), and diffusion tensor imaging (10 min). Contrary to imitation tasks previously used by Iacoboni (1999) and Williams (2006), the imitation task in our study was object-oriented (pressing buttons on a button-box). Diffusion tensor imaging data were collected to assess white matter changes associated with neurofeedback training in pathways connecting areas of the MNS.
Results: Before training, greater activation occurred in regions of interest related to MNS in TD compared to ASD during object-oriented imitation and observation. These areas of differential activation included left inferior frontal gyrus (IFG) and bilateral inferior parietal lobules. Abnormal resting state functional connectivity (both under- and over-connectivity) between MNS regions of interest was also seen in ASD compared to TD groups. Following mu neurofeedback training, ASD children showed increased activations in IFG and other relevant MNS areas, as well as normalization of functional connectivity in MNS circuits.
Conclusions: These preliminary data indicate plasticity within the mirror neuron system occurs in response to mu-based neurofeedback training in ASD. Both activation and connectivity measures were found to normalize with training.
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