# Transcriptomics reveals pallial and subpallial subdivisions of the mouse medial amygdala

## TL;DR

This study uses transcriptomics to show that the mouse medial amygdala has both pallial and subpallial subdivisions, challenging its traditional classification.

## Contribution

The paper provides new evidence for the pallial origin of the ventral medial amygdala using snRNAseq and developmental markers.

## Key findings

- The ventral medial amygdala shows molecular similarity to pallial regions like the anterior basomedial nucleus.
- The posterodorsal medial amygdala has a GABAergic profile consistent with subpallial origins.
- Radial glia analysis supports the pallial classification of the ventral medial amygdala.

## Abstract

The medial amygdala plays a key role in social brain networks supporting affiliation behavior. This whole domain is widely considered a subpallial (GABAergic) amygdalar subdivision, although it is composed of a mixture of cells of different origins, including populations migrated from the hypothalamus, the prethalamic eminence and the neighboring pallial amygdala. Specifically, the ventral part of the medial amygdala has a high percentage of glutamatergic cells. We developed a transcriptomic study (snRNAseq) to examine the pallial versus subpallial ascription of the mouse medial amygdala cells. We detected high molecular similarity between the ventral region of the medial amygdala and the pallial anterior amygdalar radial unit (classical anterior basomedial nucleus, BMA, and anterior cortical nucleus, ACo), in contrast with the GABAergic profile of the posterodorsal region of the medial amygdala, and the central and intercalated amygdalar nuclei. To verify the possible pallial origin of the ventral medial amygdala, we also analyzed pallial and subpallial marker genes in this region during development and in adult specimens. In addition, we labeled radial glia at perinatal stages to reconstruct the radial domain to which the ventral medial amygdala belongs. The results are consistent with a pallial nature of the ventral medial amygdala, while the posterodorsal medial amygdala is subpallial.

The online version contains supplementary material available at 10.1007/s00429-026-03076-x.