Journal of neurophysiology
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1. An experimental approach was developed that allowed recording of neurophysiological activity from single putative cochlear efferents in the auditory brain stem of anesthetized chickens with the use of glass micropipettes. The aim of this study was to study spontaneous and tone-evoked activity from single efferent neurons in the chick and to compare their properties with those of other vertebrate hair cell organs. ⋯ The others either showed regular spontaneous activity, or their time-interval histograms showed longer modes than ascending fibers. In general, mean spontaneous activity was lower than in ascending fibers, being < 30 spikes/s. 7. In contrast to reports from mammalian studies, in which efferents only showed on peristimulus time (PST) response pattern to tonal stimuli (chopper), two different response types were found in this study: two excitation types (chopper and primary-like) and one suppression type.(ABSTRACT TRUNCATED AT 400 WORDS)