Anatomical and functional investigation of the marmoset default mode network

Abstract

The default mode network (DMN) is associated with a wide range of brain functions. In humans, the DMN is marked by strong functional connectivity among three core regions: medial prefrontal cortex (mPFC), posterior parietal cortex (PPC), and the medial parietal and posterior cingulate cortex (PCC). Neuroimaging studies have shown that the DMN also exists in non-human primates, suggesting that it may be a conserved feature of the primate brain. Here, we found that, in common marmosets, the dorsolateral prefrontal cortex (dlPFC; peak at A8aD) has robust fMRI functional connectivity and reciprocal anatomical connections with the posterior DMN core regions (PPC and PCC), while the mPFC has weak connections with the posterior DMN core regions. This strong dlPFC but weak mPFC connectivity in marmoset differs markedly from the stereotypical DMN in humans. The mPFC may be involved in brain functions that are further developed in humans than in other primates.

Optogenetic Stimulation of Basal Forebrain Parvalbumin Neurons Activates the Default Mode Network and Associated Behaviors

“…coupling and directly implicating PV projection neurons in BF-ACC interactions. Further evidence along these lines comes from work in the macaque monkey, where transient BF local field potential activations in the BF in the gamma and other frequency ranges have been shown to precede fluctuations in cortical fMRI deflections (Liu et al, 2019). In addition to reducing exploration behavior, we observed that animals spent increased amounts of time in a state of selfgrooming during BF PV optogenetic stimulation.…”

Group Similarity Constraint Functional Brain Network Estimation for Mild Cognitive Impairment Classification

“…Changes in these subnetworks were consistent with the results of previous cognitive function studies such as those on spatial attention (Rolle et al, 2017), executive function (Liao et al, 2019), and auditory function (Bi et al, 2018) that reference subnetworks in MCI patients. Moreover, the DMN has been regarded as the core part of a functional center (Liu et al, 2019) that is involved in episodic memory and is thought to be the major cognitive domain impaired during early-stage AD (Eyler et al, 2019). That the DMN contains the most distinguishing information for MCI identification was verified using our proposed methods.…”

Structural attributes and principles of the neocortical connectome in the marmoset monkey

“…2a). Areas of the putative default mode network (DMN), including those in the posterior parietal cortex (PGM, PG, OPt, AIP), posterior cingulate cortex (A23a, A23b) and dorsolateral prefrontal cortex (A8aD, A6DR) lie in the core structure, but not those in the medial prefrontal cortex (A24d, A32, A32V), reflecting recent studies in the marmoset 23,24 .…”