Abstract
The organization of region-to-region functional connectivity has major implications for understanding information transfer and transformation between brain regions. We extended connective field mapping to 3-dimensional anatomical space to derive estimates of cortico-cortical functional organization. Using multiple publicly available resting-state fMRI data samples for model testing and replication analysis, we have three main findings. First, we found that the topology of functional connectivity between early visual regions maintained a linear relationship along the anterior-posterior dimension, which corroborates previous research. Higher order visual regions such as the fusiform face area however, showed a pattern of connectivity that supports convergence and biased sampling, which seems to contribute to their core receptive field properties. Second, we demonstrated that linearity of input is a fundamental aspect of functional connectivity of the entire cortex, with higher linearity between regions within a functional network than across networks. The principle gradient of linearity across the cortex resembled the decompositions found in previous work using conventional functional connectivity analysis and models of cortical genetic expression. Last but not least, we showed that the linearity gradients in the lateral prefrontal cortex are partially accounted for by differential dorsal and ventral stream inputs as well as increasing convergence to anterior regions, which support the concurrence of the two main theoretical accounts of prefrontal organization: domain specialization and abstraction of information processing. In sum, these findings suggest that linearity of input is a fundamental motif of functional connectivity between cortical regions for information processing and transfer, with high linearity potentially important for preserving the integrity of information from one region to another within a functional network.
Footnotes
Minor changes to figure aesthetics. Added convergence factor metric and prefrontal cortex analysis (Fig. 7, S4, S5, Table 1)