Tracheal length changes during zebra finch song and their possible role in upper vocal tract filtering.

摘要: Sounds produced in the avian vocal organ may be modified by filter properties of upper tract. Possible mechanisms to actively control characteristics include movements beak, tongue, and larynx adjustments tracheal length. We investigated whether length changes trachea are a likely mechanism for adjusting tract during song zebra finch (Taeniopygia guttata). Tracheal was monitored at basal end using sonomicrometry recorded together with subsyringeal air sac pressure acoustic output. shortening occurred onset bouts, each motif decreased expiratory pulses increased short inspirations. A bilateral syringeal nerve cut confirmed that initial bout is an active (i.e., mediated muscle activity). The modulation not affected denervation most driven pressurization interclavicular sac. absolute change small (<0.2 mm) clearly related features song. For example, some high-frequency syllables, which generated inspiration, were accompanied elongation. Because this elongation shifts tube resonances lower frequencies, it inconsistent adjustment enhance high frequency sounds. magnitude nature dynamic make unlikely they significantly affect if modeled as rigid tube.