EphrinA5 protein expression in E18.5 embryonic mouse brain. EphrinA5 protein distribution is represented on coronal sections in a rostro-caudal sequence (panels a to u) and on a sagittal section (panel v). At E18.5, ephrinA5 is mostly expressed in the telencephalon especially in olfactory structures (panels a, b) in the septum (panel f) in the lateral migratory stream (panel d) and in the cortex (panels g, m, n, v) at a moderate level. The thalamus (panel j) and inferior colliculus (panel r) showed also a moderate expression, whereas other brain structures exhibited weak ephrinA5 immunoreactivity. Arrowheads in panels f, j and r represent respectively a lateral and ventral (high) to medial and dorsal (low) gradient in the septum, a lateral and dorsal (high) to medial and ventral (low) gradient in the thalamus and a lateral (high) to medial (low) gradient in the inferior colliculus. Dotted line in panel r indicates the limit between the superior and the inferior colliculi. Scale bar: panels a, b: 250 μm; panels c, e, n: 400 μm; panels d, j, r, t: 300 μm; panels f, g, l: 200 μm; panel h: 450 μm; panels i, m: 250 μm; panel k: 100 μm; panel o: 110 μm; panel p: 175 μm; panel q: 150 μm; panel s: 100 μm, panel v: 550 μm. Abbreviations: see list.