Neurocognitive investigation of objectin-scene representations

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  • Hannah Chandler

Abstract

Organisms are required to perceive, process and remember a wealth of visual information from the environment to guide behaviour during spatial navigation. However, our knowledge is limited regarding how the brain encodes and reconstructs in memory, spatial and non-spatial properties of objects in scenes. For example, how are object locations, arrangements and identities encoded and represented across core scene-selective regions? How does the identity of a focal entity influence memory for the spatial extent of a scene? This thesis used functional magnetic resonance imaging (fMRI) and behavioural approaches across 4 independent experiments to investigate these themes. Empirical Chapters 1 and 2 employed fMRI repetition suppression (RS) to examine how activation across scene-selective regions differed in response to spatial (object Locations and Arrangements) and non-spatial (object Identities) conditions. Results revealed no effect of RS in any ROI, considered to reflect the type of task used (inversion detection). The second fMRI experiment employed a novel task, where participants responded to multiple changes between scenes. Results showed a significant effect of RS in two regions, but no dissociable effects between conditions. In two behavioural chapters, we extended these themes by using boundary extension (BE),to investigate whether memory for the spatial extent of a scene is influenced by the type of entity (object/person). Results revealed that BE was observed in both experiments for objects in scenes (in line with previous research), but not for people in scenes. Further analyses demonstrated that this effect might reflect the increase in attention assigned to people compared to objects, possibly to predict their future actions/behaviours. Together, this body of research provides insight into the mechanisms that drive RS during scene encoding, and identifies that possible differences in saliency associated with people and objects may mediate how the spatial extent of a scene is encoded and subsequently remembered.

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Original languageEnglish
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Thesis sponsors
  • Economic and Social Research Council (ESRC)
Award dateJan 2017