Preparing to sing: respiratory patterns underlying motor readiness for song

Abstract

Evidence for motor preparation and planning comes from neural activity preceding neural commands to activate the effectors; such preparatory activity is observed in pallial areas controlling learned motor behaviors. Vocal learning in songbirds is an example of a learned, sequential motor behavior that is a respiratory motor act and where there is evidence for neuromuscular planning. Respiration is the foundation of vocalization, elucidating the neural control of song motor planning requires studying respiratory antecedents of song initiation. Despite the importance of respiration in song production, few studies have investigated respiratory antecedents of impending vocalizations. Therefore, we investigated respiratory patterns in male zebra finches (Taeniopygia guttata) and Bengalese finches (Lonchura striata domestica) prior to, during, and following song bouts. In both species, compared to quiet respiration, song respiratory patterns were generated with higher amplitude, faster tempo, and ~70% of the respiratory cycle is in the expiratory phase. In female-directed and isolation song, both species show a change in the respiratory tempo and the proportion time spent inhaling prior to song. Following song, only zebra finches show systematic changes in respiratory patterns; they spend a greater proportion of the respiratory cycle in the expiratory phase for one second after song, which is likely due to hyperventilation during song. Accelerated respiratory rhythms before song may reflect the motor preparation for the upcoming song production; species differences in preparatory motor activity could be related to the degree to which motor planning is required; last, song termination may be dictated by respiratory demands.

Pervasive patterns in the songs of passerine birds resemble human music universals and are linked with production and cognitive mechanisms

“…Oscines are also more likely than suboscines to begin their songs with relatively quiet syllables, and it is possible that more oscine species begin their songs with quiet introductory elements than suboscines. The production of introductory elements and changes in respiration before oscine song is thought to reflect motor preparation for learned sequences (Rajan & Doupe, 2013;Méndez, Dukes & Cooper, 2022), and it is possible that more motor preparation is required for optimal performance of oscine song than suboscine song. Given the importance of respiratory regulation for syllable duration and amplitude, these data suggest consistent differences in the control of respiration between oscines and suboscines that may be linked to vocal learning.…”