Fig. 2.

(A) Optical recording of neural responses to N.IX stimulation in an E12 mouse medulla slice preparation. The recording was made with the caudal side up. The fast signals observed near the root of the N.IX were reversed in polarity with hyperpolarizing stimulation (data not shown), suggesting that they were not active responses but electrotonic potentials. (B) Enlarged traces of optical signals detected in the dorso-lateral region (a position indicated by an asterisk in A). The upper trace is a signal detected in a physiological solution, and the lower trace is a signal in a solution containing both APV (200 μM) and CNQX (5 μM). The slow signal was eliminated in the presence of these glutamate receptor antagonists.