Neural Correlates of Divided Attention in Natural Scenes

Abstract

Individuals are able to split attention between separate locations, but divided spatial attention incurs the additional requirement of monitoring multiple streams of information. Here, we investigated divided attention using photos of natural scenes, where the rapid categorization of familiar objects and prior knowledge about the likely positions of objects in the real world might affect the interplay between these spatial and nonspatial factors. Sixteen participants underwent fMRI during an object detection task. They were presented with scenes containing either a person or a car, located on the left or right side of the photo. Participants monitored either one or both object categories, in one or both visual hemifields. First, we investigated the interplay between spatial and nonspatial attention by comparing conditions of divided attention between categories and/or locations. We then assessed the contribution of top-down processes versus stimulus-driven signals by separately testing the effects of divided attention in target and nontarget trials. The results revealed activation of a bilateral frontoparietal network when dividing attention between the two object categories versus attending to a single category but no main effect of dividing attention between spatial locations. Within this network, the left dorsal premotor cortex and the left intraparietal sulcus were found to combine task- and stimulus-related signals. These regions showed maximal activation when participants monitored two categories at spatially separate locations and the scene included a nontarget object. We conclude that the dorsal frontoparietal cortex integrates top-down and bottom-up signals in the presence of distractors during divided attention in real-world scenes.

Large-Scale Brain Networks Supporting Divided Attention across Spatial Locations and Sensory Modalities

“…The current study aimed at characterizing large-scale brain networks supporting divided attention by re-analyzing previously reported fMRI data (Santangelo et al, 2010 ). Consistent with standard fMRI analyses reported by the previous literature (Fagioli and Macaluso, 2009 , 2016 ; Santangelo et al, 2010 ; Santangelo and Macaluso, 2013a ), the current study found that divided attention was sustained by regions belonging to the frontal and parietal cortices. However, the current data-driven approach based on ICA and CGA also revealed novel findings compared to the previous literature.…”

“…Previous research has demonstrated that monitoring of multiple streams of information typically results in a decrement of processing efficacy (Shaw and Shaw, 1977 ; Eriksen and St. James, 1986 ; Castiello and Umiltà, 1990 , 1992 ; Müller M. M. et al, 2003 ; Müller N. G. et al, 2003 ). At a neurophysiological level, divided attention was shown to recruit high-level brain regions, such as the dorsal frontoparietal attention network (Fagioli and Macaluso, 2009 , 2016 ; Santangelo et al, 2010 ), showing modulatory effects on sensory cortices deputed to process the incoming, multiple information (McMains and Somers, 2004 , 2005 ; Sreenivasan et al, 2014 ).…”

“…The analysis of the independent components (ICA) was used to highlight any large-scale brain network operating during divided attention across spatial locations vs. sensory modalities. Based on the existent literature (Fagioli and Macaluso, 2009 , 2016 ; Santangelo et al, 2010 ; Santangelo and Macaluso, 2013a ), there might be expected a main involvement of the frontoparietal network during divided attention tasks, but also brain differences related to the specific interplay between spatial- and sensory-related factors in multisensory contexts (see, Santangelo et al, 2010 ) during divided attention over different spatial locations or sensory modalities. To investigate the specific contribution of regions within the ICs supporting either divided attention across spatial locations or sensory modalities Granger Causality Analysis (GCA) was employed.…”

Overt orienting of spatial attention and corticospinal excitability during action observation are unrelated

“…Notably, visual search in composite natural situations can be remarkably fast and efficient despite the overwhelming amount of information [96,97]. Fagioli & Macaluso [98] recently suggested that two factors may influence attentional control in these contexts. First, real-world objects are recognized more quickly when they are familiar object, a phenomenon termed “ultra-rapid categorization” [99].…”

Multi-spectral oscillatory dynamics serving directed and divided attention

“…The division of attention between the auditory and visual domains activates similar brain regions as directed attention tasks in each modality, but the activation of these regions is significantly reduced when cognitive resources are divided between the two modalities ( Castiello and Umiltà, 1990 , 1992 ; Eriksen and St. James, 1986 ; Hopfinger et al, 2000 ; Johnson and Zatorre, 2006 ; Loose et al, 2003 ; Müller et al, 2003a ; Müller et al, 2003b ; Salo et al, 2015 ; Shaw and Shaw, 1977 ), suggesting resource processing limitations ( Alais et al, 2006 ; Klingberg, 1998 ; Mowbray, 1953 ; Pashler, 1994 ; Roland and Zilles, 1998 ; Welford, 1952 ). In addition to these decreased activations during divided attention, there is also generally concurrent activation in components of the dorsal frontoparietal attention network ( Corbetta et al, 2008 ; Corbetta and Shulman, 2002 ; Fagioli and Macaluso, 2009 , 2016 ; Hopfinger et al, 2000 ; Johnson et al, 2007 ; Johnson and Zatorre, 2006 ; Loose et al, 2003 ; Moisala et al, 2015 ; Nebel et al, 2006 ; Salo et al, 2015 , 2017 ; Santangelo et al, 2010 ; Schubert and Szameitat, 2003 ; Stelzel et al, 2006 ; Vohn et al, 2007 ).…”