Neuronal diversity and reciprocal connectivity between the vertebrate hippocampus and septum

Abstract

A hallmark of the nervous system is the precision with which myriad cell types are integrated into functional networks that control complex behaviors. The limbic system governs evolutionarily conserved processes essential for survival. The septum and the hippocampus are central to the limbic system, and control not only emotion‐related behaviors but also learning and memory. Here, we provide a developmental and evolutionary perspective of the hippocampus and septum and highlight the neuronal diversity and circuitry that connects these two central components of the limbic system. This article is categorized under: Nervous System Development > Vertebrates: Regional Development Nervous System Development > Vertebrates: General Principles Comparative Development and Evolution > Regulation of Organ Diversity

Cell types and clonal relations in the mouse brain revealed by single-cell and spatial transcriptomics

“…Because the number of clones containing at least one CA1 or CA3 neuron was small (42 clones with 77 CA1 cells and 11 clones with 14 CA3 cells), we cannot exclude that these cells share a common progenitor. However, our observations are in agreement with previous studies about the early specification of CA field identity 42 and might indicate a fate specification (or at least fate bias) as early as E9.5.…”

Neuronal pericellular baskets: neurotransmitter convergence and regulation of network excitability

“…In addition to this temporal axis of septal basket development, there is also a significant spatial axis, with baskets elaborating first in the medial septum and later in the lateral septum. Notably, this pattern matches that of septal neuron maturation including dendritic arborization [56]. Similar temporal dynamics describe the formation of pericellular baskets in other brain regions, such as the cerebellum [57], cortex, and hippocampus [58][59][60].…”

Transcriptional profiling of sequentially generated septal neuron fates

“…The expression of Zic family transcription factors distinguishes septal progenitor zones from adjacent regions ( Inoue et al, 2007 ). The developing septum can be further divided into pallial-like, LGE-like, and MGE/PoA-like areas demarcated by the enriched expression of transcription factors such as Tbr1 , Gsh2, and Nkx2.1 , respectively, which give rise to specific subpopulations of neurons ( Flames et al, 2007 ; Iyer and Tole, 2020 ; Puelles et al, 2000 ; Wei et al, 2012 ). The anatomically distinct MGE/PoA-like region has been previously described as the ‘ventral septum’ (vSe) to differentiate it from the septum proper ( Flames et al, 2007 ; Hoch et al, 2015b ; Hoch et al, 2009 ; Puelles et al, 2000 ; Wei et al, 2012 ).…”