Fig. 7

Pallial-like accumulation of GABAergic neurons in the adult amphioxus brain. a–f, h–o Distribution of GABAergic neurons in the adult amphioxus brain, detected by immunohistochemistry and shown in coronal (a–f) and frontal (h–o) thick vibratome sections. Planes of sectioning for frontal sections are indicated by dashed lines on the coronal sections. Coronal sections are ordered from ventral to dorsal (a to f) and frontal sections are ordered from anterior to posterior, as indicated by the dashed lines in a–f. GABAergic neurons concentrate in the dorsal half of the cv, in this region of the central nervous system. g Distribution of GABAergic neurons in one-gill-slit embryos (1GS) detected by in situ hybridisation of GAD in whole mount preparations. GABAergic neurons are at these stages located in the neural tube. Only a pair is visible at the caudal end of the cv, as indicated by the dashed line. Their ventral position is obvious in a cross section of the same embryo, shown in the inset. All scale bars are 20μm. Colour code: red, GAD/GABA; green, neuropil and intraventricular cilia (acetylated tubulin); blue/cyan, nuclear staining (Dapi)