MEG Connectivity Fingerprints of the Frontal Eye Field and Inferior-frontal Junction

Neuroimaging studies suggest FEF and IFJ subserve the encoding of spatial and non-spatial (such as feature- or object-based) representations, respectively, both during visual attention and working memory tasks. However, it is still unclear to what extent this functional specialization is reflected in their underlying functional connectivity profiles. Here, we hypothesize that FEF has predominant functional connectivity with spatiotopically organized areas in the dorsal visual stream, whereas IFJ has predominant functional connectivity with the feature-or object-encoding areas in the ventral visual pathway. We applied seed-based functional connectivity analyses to resting-.state MEG recordings. We parcellated the brain according to the multimodal Glasser atlas and tested whether the spontaneous activity of each parcel in the ventral and dorsal pathway has predominant functional connectivity with FEF or IFJ. We used both phase. And power-based metrics: Imaginary part of coherence (iCOH) and orthogonalized power envelope correlation (oPEC). Also, we inquired about the dominant directionality of these interactions between FEF/IFJ and the visual streams. Both power- (oPEC) and phase-based (iCOH) measures showed that FEF has more robust functional coupling with the spatiotopically organized regions in the dorsal visual stream. In contrast, IFJa has more substantial power and phase relation with the feature-and object-encoding regions in the ventral visual stream. We argue that intrinsic connectivity patterns are congruent with each brain region‘s function. Therefore, we conclude that FEFF‘s functional connectivity with the spatiotopically organized regions in SPL and IPS supports its role in spatial attention and working memory. In contrast, IFJa‘s functional coupling with feature- or object-based encoding areas in the inferior-temporal (IT) cortex indicates its role in non-spatial attention and working memory. FEF and IFJ have dissociable connectivity patterns that fit their respective functional roles in spatial versus non-spatial top-down attention and working memory control.