Abstract
Previous studies have reported that some objects evoke a sense of local three-dimensional space (space-defining; SD), while others do not (space-ambiguous; SA), despite being imagined or viewed in isolation devoid of a background context. Moreover, people show a strong preference for SD objects when given a choice of objects with which to mentally construct scene imagery. When deconstructing scenes, people retain significantly more SD objects than SA objects. It, therefore, seems that SD objects might enjoy a privileged role in scene construction. In the current study, we leveraged the high temporal resolution of magnetoencephalography (MEG) to compare the neural responses to SD and SA objects while they were being used to build imagined scene representations, as this has not been examined before using neuroimaging. On each trial, participants gradually built a scene image from three successive auditorily-presented object descriptions and an imagined 3D space. We then examined the neural dynamics associated with the points during scene construction when either SD or SA objects were being imagined. We found that SD objects elicited theta changes relative to SA objects in two brain regions, the right ventromedial prefrontal cortex (vmPFC) and the right superior temporal gyrus (STG). Furthermore, using dynamic causal modeling, we observed that the vmPFC drove STG activity. These findings may indicate that SD objects serve to activate schematic and conceptual knowledge in vmPFC and STG upon which scene representations are then built.
Highlights
Our lived experience of the world comprises a series of scenes that are perceived between the interruptions imposed by eye blinks and saccades
Power Changes A whole brain beamforming analysis revealed significant theta power attenuation for SD compared to SA objects in only two regions: the right ventromedial prefrontal cortex (vmPFC) and right superior temporal gyrus (STG; peak MNI = 66, −6, −12; t-value = 3.76; cluster size = 1,197; Figure 3A)
A subsequent contrast between each object type and the baseline revealed that the theta power changes were decreases, echoing numerous previous reports of power attenuation during the construction of scene imagery (e.g., Guderian et al, 2009; In this study, we focused on an object property, SD-SA, that has been shown to influence how scene imagery is constructed (Mullally and Maguire, 2013)
Summary
Our lived experience of the world comprises a series of scenes that are perceived between the interruptions imposed by eye blinks and saccades. Scene mental imagery has been shown to dominate when people engage in critical cognitive functions such as recalling the past, imagining the future, and spatial navigation (Andrews-Hanna et al, 2010; Clark et al, 2020; see Clark et al, 2019). It is not surprising, that visual scenes have been deployed extensively as stimuli in cognitive neuroscience. How are scene representations built, and what specific roles might these brain regions play? While spatial aspects of scenes have been amply investigated and linked to the hippocampus (Byrne et al, 2007; Morgan et al, 2011; Epstein et al, 2017; Epstein and Baker, 2019), the higher-order properties of objects within scenes have received comparatively less attention (Auger et al, 2012; Troiani et al, 2014; Julian et al, 2017; Epstein and Baker, 2019), and yet they could influence how scene representations are constructed by the brain
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