Functional Differentiation of Memory Retrieval Network in Macaque Posterior Parietal Cortex

Abstract

Human fMRI studies revealed involvement of the posterior parietal cortex (PPC) during memory retrieval. However, corresponding memory-related regions in macaque PPC have not been established. In this monkey fMRI study, comparisons of cortical activity during correct recognition of previously seen items and rejection of unseen items revealed two major PPC activation sites that were differentially characterized by a serial probe recognition paradigm: area PG/PGOp in inferior parietal lobule, along with the hippocampus, was more active for initial item retrieval, while area PEa/DIP in intraparietal sulcus was for the last item. Effective connectivity analyses revealed that connectivity from hippocampus to PG/PGOp, but not to PEa/DIP, increased during initial item retrieval. The two parietal areas with differential serial probe recognition profiles were embedded in two different subnetworks of the brain-wide retrieval-related regions. These functional dissociations in the macaque PPC imply the functional correspondence of retrieval-related PPC networks in macaques and humans.

The Cutting Edge in Brain Science and Sportology

“…A task-evoked connectivity network was identified based on data from the functional imaging conducted during recognition tasks (Miyamoto et al, 2013) and temporal-order judgment tasks (Osada et al, 2015). A significant positive correlation was observed between the predicted impact on performance and the betweenness centrality based on task-evoked connectivity network, whereas no correlation was observed between the predicted impact on performance and the betweenness centrality based on anatomical connectivity network.…”

“…Experimental details are described in our previous reports (Miyamoto et al, 2013;Osada et al, 2015). Four monkeys (M. mulatta and M. fuscata) were used.…”

“…Experimental details are described in our previous paper by Miyamoto et al (2013) and Osada et al (2015). In this experiment, two monkeys performed a recognition task 4) 8) or a temporal-order judgment task 6) modified for fMRI 5) .…”

“…Recently, we developed a novel approach to identify task-related brain networks 4) and this approach was extended so that it allows behavioral consequences of brain damage to be precisely predicted in primates 5) . Functional magnetic resonance imaging (fMRI) was used to measure whole-brain activity during the performance of a cognitive task (in our proof-of-concept experiments, we used well-established memory tasks).…”

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Objective: We aimed to establish a novel approach that enables the prediction of behavioral effects of lesions using neuroimaging data, which is applicable to sportological analyses, particularly in identifying the links between brain activity and behavior related to sports.

Materials and Methods:Experimental details are described in our previous reports (Miyamoto et al, 2013;Osada et al, 2015). Four monkeys (M. mulatta and M. fuscata) were used.

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