Auditory input to a vocal nucleus in the frog Rana pipiens: hormonal and seasonal effects

Summary In Rana pipiens, single unit recordings from the pretrigeminal nucleus (pre-V), a nucleus involved in call production, demonstrated neurons that respond to auditory stimuli. Most of these neurons had V-shaped tuning curves, with best excitatory frequencies between 200–1400 Hz, thresholds between 31–87 dB SPL, latencies between 10–50 ms, and Q (10 dB) between 1.3–5.1. The number of pre-V neurons that responded to acoustic stimulation increased after gonadotropin injections, and appeared to increase during the breeding season. In addition, a small number of neurons with more complex response properties, such as W-shaped tuning curves or sensitivity to white noise but not to pure tones, appeared after hormone treatments. The hormonal and possible seasonal effects on pre-V auditory activity suggest that the auditory input to this vocal nucleus may play a role in reproductive behavior.