Broad domain generality in focal regions of frontal and parietal cortex

Abstract

Unlike brain regions that respond selectively to specific kinds of information content, a number of frontal and parietal regions are thought to be domain- and process-general: that is, active during a wide variety of demanding cognitive tasks. However, most previous evidence for this functional generality in humans comes from methods that overestimate activation overlap across tasks. Here we present functional MRI evidence from single-subject analyses for broad functional generality of a specific set of brain regions: the same sets of voxels are engaged across tasks ranging from arithmetic to storing information in working memory, to inhibiting irrelevant information. These regions have a specific topography, often lying directly adjacent to domain-specific regions. Thus, in addition to domain-specific brain regions tailored to solve particular problems of longstanding importance to our species, the human brain also contains a set of functionally general regions that plausibly endow us with the cognitive flexibility necessary to solve novel problems.

Keywords: Multiple-demand system; cognitive control.

Fig. 1.

A schematic illustration of the seven tasks. (Note: The timing for the spatial WM and verbal WM tasks is identical to the timing of the Math task.) (Adapted from ref. .)

Fig. 2.

A group-level representation of the MD activity based on average activity in left and right hemispheres. To create this representation, we (i) reflected left hemisphere data to the right, (ii) averaged the resulting 14 (7 contrasts × 2 hemispheres) t-maps, and (iii) thresholded the map at t = 1.5. The map (including a parcellated version) can be downloaded at http://imaging.mrc-cbu.cam.ac.uk/imaging/MDsystem.

Fig. 3.

Average responses across subjects (expressed in percent BOLD signal change relative to the fixation baseline) of individually defined fROIs to the hard and easy condition of each of the seven tasks. In the center we show the anatomical parcels used to constrain the selection of voxels in individual subjects in blue. Each individual subject’s fROI constituted only a small portion of the anatomical parcel (see SI Text and Table S2 for details). For each region, the Upper bar graph represents the profile of the left hemisphere region, and the Lower bar graph, the right hemisphere region. The values on the y axis range from −0.04 to 2 for all fROIs except for the ParSup and ParInf fROIs where they range from 0 to 2.8. Error bars represent SEMs. IFGop, opercular part of the inferior frontal gyrus; MFG, middle frontal gyrus; MFGorb, orbital part of the middle frontal gyrus; ParInf, the inferior parietal cortex; ParSup, the superior parietal cortex; PrecG, precentral gyrus; SMA, supplementary motor area.