RESUMO
Effective connectivity based on functional magnetic resonance imaging (fMRI) allows assessing directions of interaction between brain regions. For real-time fMRI, we compared models of positive social emotion regulation based on a network involving the bilateral amygdala, dorsomedial prefrontal, and subgenual anterior cingulate cortex. The top-down regulation model implied modulation of the dorsomedial prefrontal cortex exerted onto other regions, while the bottom-up model implied the inverse modulation. The validity of model calculations was tested using the data from three healthy volunteers who imagined positive interactions with people in presented photos (stimuli). We confirmed the dominance of the top-down model and evaluated the number and duration of iterations required for model estimations. The study shows the applicability of the four-node effective connectivity models for regulation of positive social emotions using real-time fMRI, e.g., for neurofeedback applications.
RESUMO
This article discusses the contribution of fMRI- and fMRI-EEG-neurofeedback into recovery of motor function in two subacute stroke patients during the early post-stroke period. Premotor and supplementary motor zones of the cortex were chosen as the targets of voluntary control. Patient 1 received 6 sessions of motor imagery-based fMRI neurofeedback of secondary motor areas activity and Patient 2 received a similar course with the addition of µ- and ß-EEG activity suppression. Both reduced the motor deficit severity, improved on the quality of life, and increased the C3/C4 coherence to other central leads within EEG µ-band. Patient 1 reliably increased the fMRI signal in target areas and improved on the strength and speed of hand movements. Patient 2 (fMRI-EEG) mastered the EEG activity regulation to a greater degree. The authors conclude that pure fMRI neurofeedback and bi-modal fMRI-EEG neurofeedback produce different clinical effects in motor rehabilitation, which confirms the prospect of the closed-loop stroke treatment.
