RT Journal Article
SR Electronic
T1 Connection “Stripes” in the Primate Insula
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.11.03.361055
DO 10.1101/2020.11.03.361055
A1 M. Krockenberger
A1 T.O. Saleh
A1 N.K. Logothetis
A1 H.C. Evrard
YR 2020
UL http://biorxiv.org/content/early/2020/11/04/2020.11.03.361055.abstract
AB The insula has been classically divided into vast granular, dysgranular and agranular sectors. Over the years, several distinct studies proposed subdivisions of these sectors, with however no consensus. We recently proposed a cyto- and myelo-architectonic partition in which each sector contained sharply delimited areas (Evrard et al. 2014 J Comp Neurol 522: 64-97). Some of these areas were further divided into distinct subareas with obvious functional implications. Here, we examined the spatial relationship between architectonic boundaries and tract-tracing labeling in the insula in the macaque monkey. Injections of neuronal tracers in distinct areas of the prefrontal or anterior cingulate cortices produced heterogeneous and discontinuous patterns of anterograde and retrograde labeling in the insula. These patterns were made of sharply delimited patches forming anteroposterior stripes across consecutive coronal sections. While the overall pattern of labeling varied with the injection site, the patches systematically coincided with specific architectonic subareas, particularly in the dysgranular insula. This unequivocally validates our prior architectonic partition and strongly supports the idea of a refined modular Bauplan of the primate insula. This modular organization may underlie a serial stream of integration of interoception with ‘self-agency’ and ‘social’ activities across distinct insulo-prefrontal processing units that need to be explored.Competing Interest StatementThe authors have declared no competing interest.BDABiotinylated dextran amineCTbCholera toxin subunit BFRFluororubyIaiintermediate agranular area of the insulaIallateral agranular area of the insulaIammedial agranular area of the insulaIap1-2posterior agranular area of the insula, subareas 1 and 2Iaplposterior lateral agranular area of the insulaIapmposterior medial agranular area of the insulaIdd1-5dorsal dysgranular area of the insula, subareas 1 to 5Idfaanterior (granular) area of the dorsal fundus of the insulaIdfpposterior (granular) area of the dorsal fundus of the insulaIdm1-3mound dysgranular area of the insula, subareas 1 to 3Idv1-2ventral dysgranular area of the insula, subareas 1 and 2ILSInferior limiting sulcus of the insulaIvfaanterior (agranular) area of the ventral fundus of the insulaIvfpposterior (dysgranular) area of the ventral fundus of the insulaLYLucifer yellowSLSsuperior limiting sulcus of the insula