Accelerated redevelopment of vocal skills is preceded by lasting reorganization of the song motor circuitry

Abstract

Complex motor skills take considerable time and practice to learn. Without continued practice the level of skill performance quickly degrades, posing a problem for the timely utilization of skilled motor behaviors. Here we quantified the recurring development of vocal motor skills and the accompanying changes in synaptic connectivity in the brain of a songbird, while manipulating skill performance by consecutively administrating and withdrawing testosterone. We demonstrate that a songbird with prior singing experience can significantly accelerate the re-acquisition of vocal performance. We further demonstrate that an increase in vocal performance is accompanied by a pronounced synaptic pruning in the forebrain vocal motor area HVC, a reduction that is not reversed when birds stop singing. These results provide evidence that lasting synaptic changes in the motor circuitry are associated with the savings of motor skills, enabling a rapid recovery of motor performance under environmental time constraints.

Development of Perineuronal Nets during Ontogeny Correlates with Sensorimotor Vocal Learning in Canaries

“…The fourth group was subdivided into two subgroups that received a 10 mm long SILASTIC implant filled with crystalline T or left empty as control (ctrl) to study the potential effect of T-induced premature crystallization on the expression of PV and PNN (winter ctrl, n = 7; winter1T, n = 8). T has previously been shown to activate singing activity in adult male and female canaries (Madison et al, 2015;Cornez et al, 2017a;Vellema et al, 2019). These two sub-groups were recorded in early winter and their brains were collected on February third (mean age: 317 dph, range 314-320 dph) under a photoperiod of 8L:16D.…”

“…In castrated male canaries, four weeks of exposure to T progressively improved song quality as reflected by a longer duration, higher energy and decreased entropy measured at the level on entire songs (Cornez et al, 2017a). Similarly, T has been shown to promote development in female canaries of more stable male-like songs associated with lower entropy as measured at the level of individual syllables (Vellema et al, 2019). All measures were averaged for each bird and each day.…”

“…T accelerates song development in winter without increasing PNN numbers T increases singing rate and promotes the development of song features typically seen in the song of mature males (e.g., longer duration, higher energy) in castrated male and female canaries (Cornez et al, 2017a;Vellema et al, 2019). We also previously showed that T increases the number of PNN in HVC, RA, and area X in adult female and castrated male canaries (Cornez et al, 2017a).…”

Fast retrograde access to projection neuron circuits underlying vocal learning in songbirds

“…We therefore sought to test our construct on canaries. Canaries ( Serinus canaria ) are seasonal breading songbirds that produce highly complex and flexible songs with extremely fast syllable repetitions, making this species a valuable model system for complex motor skill learning 35 . Additionally, canaries are a popular model for sex hormone-induced neuroplasticity 36 .…”

Automatic bird song and syllable segmentation with an open-source deep-learning object detection method – a case study in the Collared Flycatcher (Ficedula albicollis)

“…Bird song is an important model for study the ontogeny and evolution of signals and sexual selection (Catchpole & Slater 2008, Vellema et al 2019, therefore it attracts great interest from behavioural ecologists. Furthermore, many faunistic, applied and conservational researches are based on bird song (Laiolo 2010, Borker et al 2015, Zachar et al 2019.…”