A lateralized top-down network for visuospatial attention and neglect

Abstract

The lateralization of visuospatial attention has been well investigated and demonstrated to be primarily resulting from unbalanced interaction between interhemispheric fronto-parietal networks in previous studies. Many recent studies of top-down attention have reported the neural signatures of its effects within visual cortex and identified its causal basis. However, the relationship between top-down networks and asymmetric visuospatial attention has not been well studied. In the current study, we aimed to explore the relationship between top-down connectivity and asymmetric visuospatial ability by using repetitive transcranial magnetic stimulation (rTMS) and resting-state functional connectivity (RSFC) analyses. We used rTMS and RSFC to model the virtual lesion to assess the behavioral performances in visuospatial attention shifting and to identify the behavior-related top-down functional connectivities, respectively. Furthermore, we also investigated the top-down connectivity in neglect patients to validate the RSFC findings. RSFC analyses in healthy subjects and neglect patients consistently revealed that asymmetric visuospatial ability and visuospatial neglect were closely related to the bias of top-down functional connectivity between posterior superior parietal lobule (SPL) and V1. Our findings indicate that stronger top-down connectivity has stronger dominance on its corresponding visual field. We argue that an asymmetric top-down network may represent a possible neurophysiological substrate for the ongoing functional asymmetry of visuospatial attention, and its interhemispheric unbalanced interaction could contribute to the clinical manifestations of visuospatial neglect.

Prism adaptation modulates connectivity of the intraparietal sulcus with multiple brain networks

“…Functional connectivity analysis: To initiate the analysis, we created seed regions composed of the right and left intra-parietal sulcus (IPS) regions 1 and 2, where transcranial magnetic stimulation causes changes in visuospatial behavior when applied online (Szczepanski and Kastner, 2013). We identified these regions of interest using a probabilistic atlas of the visual areas (Wang et al, 2015). We created each seed by transforming the IPS 1 and 2 maps from the probabilistic atlas into TT_N27 template space and keeping voxels that had ≥ 30% probability of classification as being in IPS 1 or 2.…”

Functional reorganization of intra‐ and internetwork connectivity in major depressive disorder after electroconvulsive therapy

“…The DMN primarily participates in self‐referential functioning and autobiographical memory (Buckner, Andrews‐Hanna, & Schacter, ; Raichle et al, ; Zhang et al, ). In contrast to the DMN, the DAN is typically involved in top‐down attention processing, and the ECN in the management of exogenous cognitive functions, and externally guided cognition (Corbetta & Shulman, ; Seeley et al, ; Sridharan, Levitin, & Menon, ; Wang et al, ). The SAL and SMN are separately implicated in allocating attentional resource to salient events, sensory‐motor processing, and emotional experience (Lindquist, Wager, Kober, Bliss‐Moreau, & Barrett, ; Menon & Uddin, ; Menon, ).…”

Changed Hub and Corresponding Functional Connectivity of Subgenual Anterior Cingulate Cortex in Major Depressive Disorder

“…Resting-state functional MRI (rs-fMRI), which primarily reflects ongoing spontaneous fluctuations in the human brain, can non-invasively investigate the functional coupling between brain regions to detect intrinsic functional changes and abnormal functional modules (Fox et al, 2006; Buckner et al, 2009; Power et al, 2011; Yeo et al, 2011; Wang et al, 2012, 2015a,b; Cole et al, 2014; Wang J. et al, 2016; Mears and Pollard, 2016). In the brain, a few highly connected and central regions, the so-called hub nodes, play a key role in the global topology of the brain’s network (Hagmann et al, 2008; Bullmore and Sporns, 2009).…”