  Real-time fMRI neurofeedback (rtfMRI-nf) with simultaneous EEG allows
volitional modulation of BOLD activity of target brain regions and
investigation of related electrophysiological activity. We applied this
approach to study correlations between thalamic BOLD activity and alpha EEG
rhythm. Healthy volunteers in the experimental group (EG, n=15) learned to
upregulate BOLD activity of the target region consisting of the mediodorsal
(MD) and anterior (AN) thalamic nuclei using the rtfMRI-nf during retrieval of
happy autobiographical memories. Healthy subjects in the control group (CG,
n=14) were provided with a sham feedback. The EG participants were able to
significantly increase BOLD activities of the MD and AN. Functional
connectivity between the MD and the inferior precuneus was significantly
enhanced during the rtfMRI-nf task. Average individual changes in the occipital
alpha EEG power significantly correlated with the average MD BOLD activity
levels for the EG. Temporal correlations between the occipital alpha EEG power
and BOLD activities of the MD and AN were significantly enhanced, during the
rtfMRI-nf task, for the EG compared to the CG. Temporal correlations with the
alpha power were also significantly enhanced for the posterior nodes of the
default mode network, including the precuneus/posterior cingulate, and for the
dorsal striatum. Our findings suggest that the temporal correlation between the
MD BOLD activity and posterior alpha EEG power is modulated by the interaction
between the MD and the inferior precuneus, reflected in their functional
connectivity. Our results demonstrate the potential of the rtfMRI-nf with
simultaneous EEG for non-invasive neuromodulation studies of human brain
function.
