Date of Award

2016

Document Type

Open Access Thesis

Department

Psychology

Sub-Department

College of Arts and Sciences

First Advisor

Rutvik Desai

Abstract

Little is known about the neural basis of temporal concepts. Some have suggested that temporal concepts are grounded in spatial or temporal processes. Here we aimed to examine the representation of duration of event concepts, and compare them with judgments of object size, which may entail spatial processing. A 2x2 block design used event and object nouns as stimuli that were presented during functional imaging. Participants made judgments about event duration, object size, and event and object valence. In addition to whole-brain analyses, we examined activations in areas known to be involved in temporal processing and spatial processing. Knowledge of events compared to objects activated a distributed network with large clusters in bilateral angular gyri, precuneus, middle temporal lobules and prefrontal cortices in whole-brain analyses. The whole-brain analyses of duration minus valence revealed a right hemispheric preference for processing of semantic duration information compared to valence tasks. Peak activation of clusters for duration were located in the right dorsomedial prefrontal cortex, precuneus, lingual gyrus, SMG, left middle MTG/ITG, parahippocampal gyrus and bilateral angular gyri. ROI analyses of angular gyri suggested the processing of semantic information of duration occurred mainly the right AG and left PGp. ROI analyses of temporal perception areas suggested a role of the right SMG in the representation of duration. Additionally, temporal ROIs suggested that the right pSTS and left SMG were involved in event processing relative to objects. IPS ROI revealed that the right middle IPS was activated for event duration minus event valence and object size minus object valance. Additionally, PPA ROI revealed that event duration compared to event valence and object size compared to object valence activated the PPA. Thus, we found that event concepts were supported by bilateral inferior parietal and anterior and middle temporal cortex, as well as precuneus and posterior cingulate. This is consistent with the role of AG in integrating temporal sequences. Conceptual duration processing is grounded in both temporal perception (right SMG) and space (IPS and PPA).

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