Coding of narrow-band and wide-band vocalizations in the auditory midbrain nucleus (MLD) of the Guinea Fowl (Numida meleagris)
1. Auditory responses have been recorded from forty-five single neurones in the lateral mesencephalic nucleus of the dove, confirming the suspected auditory function of this nucleus.2. Most of the neurones with sustained responses to tones fell into three response-categories: inhibitory only, excitatory in a central range of frequencies with inhibition in adjacent frequency regions, and predominantly inhibitory with one or more relatively small excitatory regions. Seven of the neurones studied showed only transient responses: these had high thresholds or were restricted to a narrow range of frequencies.3. Responses to clicks were sometimes obtained, but were variable in different units and in a single unit were often dependent on repetition rate.4. Many properties of these neurones are similar to those in the cat inferior colliculus. The most notable difference is the existence in the dove of neurones with exclusively or predominantly inhibitory responses.