Functional Connectivity of Brain Regions Resulting from Learning Unfamiliar Words: Word Frequency Effect

The study is aimed to investigate the change in functional interactions of brain regions during the learning process with fMRI. It was assumed that a word training, during which the meanings of a language words were assigned to certain pseudo-words, had an impact on the functional interactions of structures, primarily involved in semantic processing, as well as in the processes of involuntary attention. The ROI’s were divided into 2 groups. The first group united the regions involved in semantic processing, the second group—associated with involuntary attention and involved in the generation of MMN. The results obtained described synchronous changes in functional connectivity after learning in the selected regions. As a result of training, it was possible to show how the functional connectivity of the involved regions had changed in the parameters of the hemodynamic response. The analysis of the semantic network revealed a simultaneous increase in cerebral blood flow in the posterior superior and middle temporal gyrus, as well as in the anterior superior temporal gyrus and in the insula after the semantization. Functional connectivity changes in ROI associated with the involuntary attention were manifested by a simultaneous decrease in the BOLD signal during the deviant stimuli perception.