Neurofunctional and Neuroanatomical Hippocampal Deficits and Connectivity Differences in Schizophrenia Compared to Healthy Control Participants Tested on a Virtual Reality Navigation Wayfinding Task: An fMRI, VBM and Effective Connectivity Study

FieldValue
dc.contributor.authorLedoux, Andrée-Anne
dc.date.accessioned2013-04-24T18:51:15Z
dc.date.available2013-04-24T18:51:15Z
dc.date.created2013
dc.date.issued2013
dc.identifier.urihttp://hdl.handle.net/10393/24063
dc.identifier.urihttp://dx.doi.org/10.20381/ruor-2961
dc.description.abstractEpisodic memory is a key feature in learning. One must remember past events to act upon a present situation. Episodic memory has been reported to be impaired in individuals with schizophrenia. In order to have an intact episodic memory the contextual features (context) must be bound to the content of the event; this mechanism is referred to as contextual binding. It is proposed that binding errors during the encoding process are responsible for episodic memory impairments in schizophrenia. Since the hippocampal formation is considered to be the central element for contextual binding, it is hypothesized that the synaptic disorganization described in this condition results in such a deficit. Moreover, the hippocampus mediates and influences other cognitive processes such as learning and executive functioning. Hence, a contextual binding deficit can have important consequences on cognition, behaviour and emotions. The object of this dissertation was to investigate the neurofunctioning, neuroanatomy and neurofunctional connectivity of the hippocampus while performing a task that utilized contextual binding mechanisms. Since spatial relational processing is part of contextual binding and is rooted in the hippocampal regions, visuospatial navigation, more precisely a wayfinding task, was used as a probe to activate the hippocampus and its associated regions in a group of patients with schizophrenia and matched healthy controls. The following dissertation presents three original research papers contributing to our understanding of the contextual binding and hippocampal deficits in schizophrenia. The first paper investigates the neurofunctioning of the hippocampus with a wayfinding task. The second paper investigates the hippocampal structural abnormality in schizophrenia and how it relates to performance during the wayfinding task. The third paper explores effective connectivity of the hippocampus with other brain regions involved in navigation in schizophrenia with a particular interest in the prefrontal cortex. These three studies demonstrate significant neurofunctional, neuroanatomical, and neurofunctional connectivity deficits in the hippocampus of the patients with schizophrenia compared to a healthy control population. Results of all three papers are further discussed in terms of research and clinical implications.
dc.language.isoen
dc.publisherUniversité d'Ottawa / University of Ottawa
dc.subjectSchizophrenia
dc.subjectVisuospatial navigation
dc.subjectWayfinding
dc.subjectHippocampus
dc.subjectfMRI
dc.subjectVBM
dc.subjectEffective connectivity
dc.subjectEpisodic memory
dc.subjectContextual binding
dc.subjectVirtual reality
dc.subjectControl participants
dc.titleNeurofunctional and Neuroanatomical Hippocampal Deficits and Connectivity Differences in Schizophrenia Compared to Healthy Control Participants Tested on a Virtual Reality Navigation Wayfinding Task: An fMRI, VBM and Effective Connectivity Study
dc.typeThesis
dc.faculty.departmentPsychologie / Psychology
dc.contributor.supervisorSmith, Andra
dc.embargo.termsimmediate
dc.degree.namePhD
dc.degree.leveldoctorate
dc.degree.disciplineSciences sociales / Social Sciences
thesis.degree.namePhD
thesis.degree.levelDoctoral
thesis.degree.disciplineSciences sociales / Social Sciences
uottawa.departmentPsychologie / Psychology
CollectionThèses, 2011 - // Theses, 2011 -

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