Functional connectivity of the hippocampus and its subfields in resting-state networks

First published: 30 March 2021Many neuroimaging studies have shown that the hippocampus participates in a resting-state network called the default mode network. However, how the hippocampus connects to the default mode network, whether the hippocampus connects to other resting-state networks and how the different hippocampal subfields take part in resting-state networks remains poorly understood. Here, we examined these issues using the high spatial-resolution 7T resting-state fMRI dataset from the Human Connectome Project. We used data-driven techniques that relied on spatially-restricted Independent Component Analysis, Dual Regression and linear mixed-effect group-analyses based on participant-specific brain morphology. The results revealed two main activity hotspots inside the hippocampus. The first hotspot was located in an anterior location and was correlated with the somatomotor network. This network was subserved by co-activity in the CA1, CA3, CA4 and Dentate Gyrus fields. In addition, there was an activity hotspot that extended from middle to posterior locations along the hippocampal long-axis and correlated with the default mode network. This network reflected activity in the Subiculum, CA4 and Dentate Gyrus fields. These results show how different sections of the hippocampus participate in two known resting-state networks and how these two resting-state networks depend on different configurations of hippocampal subfield co-activity.Agencia Canaria de Investigación, Innovación y Sociedad de la Información; Ministerio de Ciencia, Innovación y Universidades, Grant/Award Number: PSI2017-84933- P, PSI2017-91955- EXP and TEC2016-80063- C3- 2- R; NIH Blueprint for Neuroscience Research, Grant/Award Number: 1U54MH091657; McDonnell Center for Systems Neuroscience; European Social Fund (ESF

Interview with the Co-ordinator of the Malta Neuroscience Network

Iggy Fenech interviews the Co-ordinator of the Malta Neuroscience Network, Professor Giuseppe Di Giovanni. He is a neuroscientist. For more than 2 decades, his research has focused on understanding the patho- physiology of central monoaminergic systems in di fferent neuropsychiatric disorders such as depression, schizophrenia, drug abuse, Parkinson's disease and epilepsy.peer-reviewe

Centralized and distributed cognitive task processing in the human connectome

A key question in modern neuroscience is how cognitive changes in a human brain can be quantified and captured by functional connectomes (FC) . A systematic approach to measure pairwise functional distance at different brain states is lacking. This would provide a straight-forward way to quantify differences in cognitive processing across tasks; also, it would help in relating these differences in task-based FCs to the underlying structural network. Here we propose a framework, based on the concept of Jensen-Shannon divergence, to map the task-rest connectivity distance between tasks and resting-state FC. We show how this information theoretical measure allows for quantifying connectivity changes in distributed and centralized processing in functional networks. We study resting-state and seven tasks from the Human Connectome Project dataset to obtain the most distant links across tasks. We investigate how these changes are associated to different functional brain networks, and use the proposed measure to infer changes in the information processing regimes. Furthermore, we show how the FC distance from resting state is shaped by structural connectivity, and to what extent this relationship depends on the task. This framework provides a well grounded mathematical quantification of connectivity changes associated to cognitive processing in large-scale brain networks.Comment: 22 pages main, 6 pages supplementary, 6 figures, 5 supplementary figures, 1 table, 1 supplementary table. arXiv admin note: text overlap with arXiv:1710.0219

Interview with the Coordinator Prof. Giuseppe Di Giovanni, University of Malta, Department of Physiology and Biochemistry

Interview with the Coordinator of the Malta Neuroscience Network Programme, Prof. Giuseppe Di Giovanni regarding the Malta Neuroscience Net- work. "With the creation of the Malta Neuroscience Network, we will be keeping up with the most important developments with regard to brain research world- wide: multi-disciplinary collaboration. Understanding the way the brain works, and above all brain diseases is extremely complicated, and requires the involvement of researchers coming from a number of diff erent scientifi c disciplines and clinical areas collaborating in new ways."peer-reviewe

A mechanistic model of connector hubs, modularity, and cognition

The human brain network is modular--comprised of communities of tightly interconnected nodes. This network contains local hubs, which have many connections within their own communities, and connector hubs, which have connections diversely distributed across communities. A mechanistic understanding of these hubs and how they support cognition has not been demonstrated. Here, we leveraged individual differences in hub connectivity and cognition. We show that a model of hub connectivity accurately predicts the cognitive performance of 476 individuals in four distinct tasks. Moreover, there is a general optimal network structure for cognitive performance--individuals with diversely connected hubs and consequent modular brain networks exhibit increased cognitive performance, regardless of the task. Critically, we find evidence consistent with a mechanistic model in which connector hubs tune the connectivity of their neighbors to be more modular while allowing for task appropriate information integration across communities, which increases global modularity and cognitive performance