A circuit for detection of interaural time differences in the nucleus laminaris of turtles.

摘要: ABSTRACT The physiological hearing range of turtles is approximately 50–1000 Hz, as determined by cochlear microphonics ( Wever and Vernon, 1956a). These low frequencies can constrain sound localization, particularly in red-eared slider turtles, which are freshwater with small heads isolated middle ears. To determine if these were sensitive to interaural time differences (ITDs), we investigated the connections physiology their auditory brainstem nuclei. Tract tracing experiments showed that cranial nerve VIII bifurcated terminate first-order nucleus magnocellularis (NM) angularis (NA), NM projected bilaterally laminaris (NL). As NL received inputs from each side, developed an head preparation examine responses binaural stimulation. Magnocellularis units responded 100 600 Hz, phase-locked reliably stimulus. Responses binaural, ITD. Measures characteristic delay revealed best ITDs around ±200 μs, neurons typically had phases close 0, consistent excitation. Thus, encode within range, nuclei have similar cell types other reptiles.