Spatial Information Modulates the Neurocognitive Dynamics of Episodic Autobiographical Memory Retrieval
Year: 2018
Type: dissertation
Abstract: Episodic autobiographical memory (EAM) enables reliving past experiences, recalling the sensory information associated with that event. Spatial information is thought to play an early and important role in EAM, contributing to the dynamics of retrieval. Using a combination of behavioural, neuroimaging, and neurostimulation approaches, this dissertation aimed to examine the temporal dynamics of EAM and the role spatial information plays in its retrieval. Chapter 2 demonstrated a temporal precedence for spatial information at the behavioural level, but importantly found high individual variability in early recall of spatial information. Further, individual differences in spatial aspects of EAM were reflected in hippocampal and precuneus grey matter volumes. Chapter 3 examined the temporal dynamics of EAM at the neural level using magnetoencephalography (MEG). While cueing individuals with familiar locations altered the dynamics of retrieval, it did not confer an early neural advantage. Together with the findings from Chapter 2, these results indicate that early spatial information alters the dynamics of EAM retrieval, but does not play a ubiquitous or automatic role in EAM. This study also found that spatial perspective during EAM retrieval was associated with a well-established neural component of episodic memory recollection. Transcranial magnetic stimulation (TMS) administered to the precuneus disrupted this association, demonstrating that this region is crucially involved in neural processing of spatial perspective during EAM. In Chapter 4, I assessed how regions representing spatial information, such as the precuneus and medial temporal lobe (MTL), interact dynamically during EAM retrieval. Using MEG to measure oscillatory activity, this study found that theta (3-7 Hz) and high gamma (65-85 Hz) oscillations underlie MTL-parietal communication, demonstrating the importance of coupling between theta and gamma oscillations in EAM. TMS to the precuneus disrupted this oscillatory activity, suggesting that this region plays a causal role in network-wide theta and gamma oscillatory activity. Together, these studies elucidate the behavioural and neural dynamics of EAM retrieval, as well as spatial contributions to EAM. Future research is needed to further clarify the key contributions of specific regions and the dynamic activity underlying widespread neural communication during EAM.
Source: TSpace (University of Toronto)
Author: Melissa Hebscher
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2997747416