Local and long-distance organization of prefrontal cortex circuits in the marmoset brain

Abstract

The primate prefrontal cortex (PFC) has greatly expanded to evolve specialized architecture, but its roles in top-down brain control remain enigmatic. Based on connectomics mapping of the marmoset PFC, we characterized two contrasting features of corticocortical and corticostriatal projections. One is the "focalness" of projections, exemplified by multiple columnar axonal terminations in the cortical layers and the other is the "widespreadness" of weaker projections, whose patterns consisted of several common motifs representing the framework of PFC connectivity. We clarified the topographic rules of distribution for these features, which should constrain how PFC neurons can coordinate to control the target regions as populations. These features are observed only primitively in rodents and are considered critical in understanding the roles of the PFC in neuropsychiatric disorders.

The Brain/MINDS Marmoset Connectivity Atlas: exploring bidirectional tracing and tractography in the same stereotaxic space

“…The Explorer includes anterograde tracer image data obtained in 52 marmosets from the Brain/MINDS project ( Watakabe et al, 2021 ). In 19 animals, they are complemented with retrograde tracer data.…”

“…Further, the BMCA-Explorer provides brain annotations for the Brain/MINDS atlas ( Woodward et al, 2018 ), the Marmoset Brain Connectivity Atlas ( Majka et al, 2020 ), and the gray and white matter atlases of the Marmoset Brain Mapping project ( Liu et al, 2018, 2020 ). It also includes annotations of major cortical and subcortical regions for the current STPT template ( Watakabe et al, 2021 ).…”

“…Further, the BMCA integrates anterograde tracer data with retrograde tracer data. Our recent study has shown that signals from combined anterograde and retrograde tracer injections correlate well in the PFC, suggesting a strong correlation between projection patterns and back projection patterns ( Watakabe et al, 2021 ). However, there are consistent reports of non-reciprocal pathways in both the macaque and marmoset brain ( Theodoni et al, 2022 ), and the combination of both tracer modalities is the best approach to further investigate this issue.…”

“…Here we introduce the implementation and features of the Brain/MINDS Marmoset Connectivity Atlas (BMCA), a public access resource that provides a significant new step towards the exploration of the structural basis of primate cognition. The BMCA is built on datasets collected by the Brain/MINDS project( Watakabe et al, 2021 ), which derived from TET-amplified AAV anterograde neural tracer injections into various locations in the marmoset PFC, one of the key regions that differentiate primates from other mammals. This core database contains data from 52 anterograde neural tracer injections in adult marmosets and has complementary structural MR images.…”

A Spiking Neural Network Builder for Systematic Data-to-Model Workflow

“…Japan's Brain/MINDS project (Brain Mapping by Integrated Neurotechnologies for Disease Studies, https://brainminds.jp/en/ ; Okano et al, 2016 ) is building a multi-scale marmoset brain map with structural and functional imaging. Images are obtained from diffusion MRI, systematic tracer injections (Skibbe et al, 2019 ; Gutierrez et al, 2020 ; Watakabe et al, 2021 ), and many types of fluorescent calcium imaging. SNNbuilder seeks to integrate such diverse, large-scale data into computational modeling, and open data and tools from other brain projects.…”