Differential coupling of visual cortex with default network or frontal-parietal network based on goals

The relationship between top-down enhancement and suppression of sensory cortical activity and large-scale, neural-networks remains unclear. Functional connectivity analysis of human fMRI data revealed visual cortical areas that selectively process relevant information are functionally connected with the frontal-parietal network, while those processing irrelevant information are simultaneously coupled with the default-network. This provides the first evidence that sensory cortical regions are differentially and dynamically coupled with distinct networks based on task goals. Goal-directed decisions influence our perception and result in corresponding modulation of sensory cortical activity. This phenomenon, known as top-down modulation, is characterized by increased cortical responses when stimuli are task-relevant (i.e., enhancement) and decreased responses when stimuli are task-irrelevant (i.e., suppression) 1, 2. It is this modulatory ability that allows us to successfully navigate multiple streams of sensory information in a flexible manner. Top-down modulation is not thought to be an intrinsic property of visual cortices, but rather achieved via distributed connections between brain regions, or neural-networks, notably involving the prefrontal cortex, parietal cortex and the visual association cortex 3-5. Recent evidence suggests that enhancement and suppression are distinct neural processes; e.g., they are differentially impacted by aging 6 and cognitive load manipulations 7. Similar to top-down modulation of sensory cortices, distinct sets of parietal and frontal regions exhibit enhanced and suppressed activity depending upon an individual's goals. Specifically, the frontal-parietal network (FPN) 8, 9 is co-activated during a wide-array of externally-directed tasks (e.g., selective attention 3, 10), while the default network 9, 11 is de-Users may view, print, copy, download and text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: activated during these tasks 11 and actived by introspective cognitive processes (e.g. prospective/retrospective memory, internal monitoring 12). To our knowledge, the relationship between these large-scale networks and top-down enhancement and suppression of sensory cortical activity has not been reported. The present study evaluated whole-brain networks associated with top-down modulation in the setting of simultaneous, competing visual processing demands. We utilized fMRI during a selective, delayed-recognition task in which participants were required to remember specific stimuli, while simultaneously ignoring irrelevant stimuli (i.e., superimposed faces and natural scenes) over a brief delay period 13 (Fig. 1). Both working memory accuracy and response time were negatively impacted by the presence of irrelevant stimuli, compared to trials where relevant stimuli were presented in isolation (Supplementary Fig. 1). To derive …