Figure 2.
Anterior-odd rhombomeric code for the induction of EP+. Integrated glossopharyngeal (A, B) or trigeminal (C) neurograms obtained after heterotopic grafting and isolation. Transplantations of the odd r3 (in r5 position; A, arrowhead) and of the even r6 (in r4 position; B, arrowhead) or r2 (in r4 position; C, arrowhead) lead to r3r6 or r3r2 preparations showing an episodic patterning similar to that obtained from the normal configuration r3r4. D, E, Summary histograms of the frequencies of LF bursts and LF + HF bursts (D, filled and empty bars, respectively) and of CV (E) obtained after pooling preparations according to the heterotopic status of either odd (r3, r5) or even (r2, r4, r6) rhombomeres (detailed in Table 1) and the anterior or posterior status of the displacement along the neuroaxis (anterior shift and posterior shift) of rhombomeres, whatever their parity (detailed in Table 1). In all cases, an EP+ pattern comparable with that of the normal r3r4 pair resulted. Surgical isolation, shift, and grafting of rhombomeres do not interfere with the development of the EP+ in artificial rhombomere pairs in which the odd rhombomere is in contact with the anterior edge of the even rhombomere. Scale bar, 1 min.