Abstract
Episodic memory retrieval most often recruits multiple separate processes that are thought to involve different temporal regions. Previous studies suggest dissociable regions in the left lateral parietal cortex that are associated with the retrieval processes. Moreover, studies using resting-state functional connectivity (RSFC) have provided evidence for the temporo-parietal memory networks that may support the retrieval processes. In this functional MRI study, we tested functional significance of the memory networks by examining functional connectivity of brain activity during episodic retrieval in the temporal and parietal regions of the memory networks. Recency judgments, judgments of the temporal order of past events, can be achieved by at least two retrieval processes, relational and item-based. Neuroimaging results revealed several temporal and parietal activations associated with relational/item-based recency judgments. Significant RSFC was observed between one parahippocampal region and one left lateral parietal region associated with relational recency judgments, and between four lateral temporal regions and another left lateral parietal region associated with item-based recency judgments. Functional connectivity during task was found to be significant between the parahippocampal region and the parietal region in the RSFC network associated with relational recency judgments. However, out of the four tempo-parietal RSFC networks associated with item-based recency judgments, only one of them (between the left posterior lateral temporal region and the left lateral parietal region) showed significant functional connectivity during task. These results highlight the contrasting roles of the parahippocampal and the lateral temporal regions in recency judgments, and suggest that only a part of the tempo-parietal RSFC networks are recruited to support particular retrieval processes.
Highlights
Retrieval of past episodes recruits multiple processes, such as recollection and familiarity during item recognition, and these processes are thought to involve different regions in the temporal lobe [1,2,3,4,5,6,7,8,9]
In the present functional MRI study, we examined functional connectivity based on inter-subject correlation of the brain activity during task between the regions of interest (ROIs) in the resting-state functional connectivity (RSFC) networks
The present study examined whether the RSFC-based temporoparietal memory networks showed functional connectivity of brain activity associated with recency judgments
Summary
Retrieval of past episodes recruits multiple processes, such as recollection and familiarity during item recognition, and these processes are thought to involve different regions in the temporal lobe [1,2,3,4,5,6,7,8,9]. Studies of resting-state functional connectivity (RSFC) have revealed significant connectivity between the temporal and parietal regions that may support the retrieval processes [18,19,20,21]. The task-related brain activity in the regions of the RSFC network during particular psychological processes may not show functional connectivity [45], which is considered more directly linked to neural mechanisms supporting the psychological processes. It is to be elucidated whether the taskrelated brain activity in the temporo-parietal memory RSFC network shows functional connectivity to support the memory retrieval processes required in the task
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
