A radial histogenetic model of the mouse pallial amygdala

Conventional anatomic models of the rodent (mammalian) amygdala are based on section planes oblique to its intrinsic radial glial organization. As a result, we still lack a model of amygdalar histogenesis in terms of radial units (progenitor domains and related radial migration and layering patterns). A radial model of the mouse pallial amygdala is first offered here, based on three logical steps: (1) analysis of amygdalar radial structure in variously discriminative genoarchitectonic material, using an optimal ad hoc section plane; (2) testing preliminary models with experiments labelling at the brain surface single packets of radial glia processes, to be followed into the ventricular surface across intervening predicted elements; (3) selection of 81 differential amygdalar gene markers and checking planar and radial aspects of their distribution across the model elements. This approach shows that subtle changes to the conventional schema of the amygdala allow a radial histogenetic model to be recognized, which is consistent with molecularly coded differential identities of its units and strata. It is expected that this model will help both causal studies of amygdalar developmental patterning and comparative evolutionary studies. It also may have potential impact on hodological and functional studies.