Movies of our minds: Hierarchical neural patterns of event, scene, and object construction
Poster No:
980
Submission Type:
Abstract Submission
Authors:
Pitshaporn Leelaarporn1, Julia Taube1, Yilmaz Sagik2, Cornelia McCormick1
Institutions:
1University Hospital Bonn, Bonn, NRW, 2German Center for Neurodegenerative Diseases, Bonn, NRW
First Author:
Co-Author(s):
Introduction:
Most of us can easily conjure up detail-rich mental events to envision future scenarios, remember past events or indulge in fictitious day-dreaming[1]. Neurally, these types of events are thought to rely on hierarchical neural structures involving the ventromedial prefrontal cortex (vmPFC), hippocampus, and visuoperceptual cortex (VC)[2,3]. In this hierarchy, we have proposed earlier that the vmPFC maybe the apex, initiating, and coordinating hippocampal scene construction processes to support the elaboration of vivid mental extended events[4,5]. We further proposed that the hippocampus constructs spatially coherent mental scenes6,7 and directs activity in the VC which may be involved in assembling rich details needed to populate scenes within events4. Original data supporting this thesis are missing. Therefore, we contrast event, scene, and object imagery to expose the underlying neural hierarchy. Our hypothesis deems a hierarchy indicating that the vmPFC supports mental events greater than scenes and objects, the hippocampus supports event and scene imagery greater than object imagery, and that the VC supports all three constructions equally.
Methods:
20 healthy young right-handed individuals (age: 28 ± 3.49 years old, Males: 8, years of education: 19.4 ± 3.71 years) were recruited with informed consent to complete an experimental fMRI task consisting of four different types of word cues imagery: objects (e.g., espresso), scenes (e.g., mountain range), events (e.g., concert), and non-words (e.g., Tribuomnus). Participants were instructed to construct mental visuoperceptual images of each of the word cues, followed by their rating of their own ability to visualize. The MRI protocol included a whole-brain T1-weighted scan and task-based rapid whole-brain submillimeter functional MRI (fMRI) sequences, acquired using a MAGNETOM 7T Plus ultra-high field scanner (Siemens Healthineers, Germany). fMRI preprocessing was performed using SPM12 software package. Using a GLM model, we analyzed the imagery time (5 s) for each imagery type as mini-blocks. 1-sample t-contrasts were calculated and thresholded at p<0.001, unc.: 1. Events <> Scenes, 2. Scenes <> Objects, 3. Events > Non-words, 4. Scenes > Non-words, and 5. Objects > Non-words. Regions-of-interest (ROI) spheres with a diameter of 5 mm were created for the right vmPFC, hippocampus, and VC and % signal change was extracted using the contrasts 3, 4, and 5, and was then assessed using 1-way RM-ANOVA with Tukey's multiple comparison test.
Results:
Figures 1 and 2 illustrate that the vmPFC showed stronger activation for event imagery than scene and object imagery, and the hippocampus showed stronger activation for both event and scene imagery in contrast to object imagery. Furthermore, the VC showed no preference for event, scene, or object imagery. Some other brain regions also exhibited preferential activation patterns which will be discussed in more detail later. Furthermore, effective connectivity models may provide more detailed insights into the hierarchical nature of these relationships. These results suggest that there is a hierarchy of neural structures supporting our ability to construct detail-rich extended mental events in front of our mind's eye, with the vmPFC being at the apex, initiating, and directing our minds' movies construction.
Conclusions:
Here, we set out to examine the specific contributions of the vmPFC, hippocampus, and VC to the construction of detail-rich mental extended events. We presented event-, scene-, and object-cues to participants during fMRI scanning and asked participants to imagine the displayed cues. With these tight contrasts, we found that the vmPFC preferentially supported event construction, whereas the hippocampus supported both event and scene construction. In addition, the VC supported all three types of mental imagery. These results provide the first evidence that these brain regions align on a hierarchy, potentially expanding the visual process stream up to the vmPFC.
Higher Cognitive Functions:
Imagery 1
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI) 2
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Cortical Anatomy and Brain Mapping
Keywords:
Cognition
Cortex
Experimental Design
FUNCTIONAL MRI
MRI
STRUCTURAL MRI
Sub-Cortical
1|2Indicates the priority used for review
Provide references using author date format
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3. Pearson, J., Naselaris, T., Holmes, E. A., & Kosslyn, S. M. (2015). Mental imagery: functional mechanisms and clinical applications. Trends in cognitive sciences, 19(10), 590-602.
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