1. Understanding mechanisms underlying intrinsic motivation for vocal practice in songbirds.

Intrinsic motivation, which drives animals, including humans, to exhibit various voluntary behaviors, spontaneously originates within the brain without immediate external stimuli such as rewards or punishments (Fig. A below). Songbirds such as zebra finches offer a unique opportunity to study mechanisms of intrinsic motivation because they spontaneously produce many renditions of songs even in the absence of apparent recipients mainly for vocal practice (Fig. B below).  

We are investigating neural mechanisms of intrinsic singing motivation using a behavioral paradigm that we have established to enhance singing motivation (Kim et al. 2021, Sci. Rep.)(Fig. A below). We recently found that a septal barain area, the nucleus of the hippocampal commissure (NHpC), is related to intrinsic singing motivation using a neuronal activation maker an immediate early gene Arc (Mori et al. 2025, Sci. Rep.)(Fig. B below).

2. Understanding physiological and behavioral mechanisms of dawn chorus in songbirds

Many species of songbirds sing vigorously in the early morning hours. This well-known occurrence is referred to as the "dawn chorus (DC)" and has been recognized as a significant biological indicator of the start of the day across the world since ancient times. Despite its widespread presence, the functions and underlying mechanisms of the DC still hold many mysteries. Our research aims to comprehensively understand this mysterious behavior from both proximate and ultimate causes through interdisciplinary research that bridges neuroscientists and ecologists studying who study birdsong. We recently found that intense morning singing resembling the dawn chorus is evoked as a rebound from singing suppression prior to dawn in captive zebra finches, providing a plausible mechanistic explanation for this misterious phenomenon (dos Santos et al. under review)(Fig. A below). We are also conducting manipulative experiments to test this hypothesis in captive songbirds housed in semi-natural conditions (Fig. B below). 

3. Understanding how songbirds modify and optimize their vocal performance using the basal ganglia-thalamo-cortical circuit and the auditory feedback.

Songbirds learn to produce complex vocalizations (song) using a discrete and specialized circuit called the anterior forebrain pathway (AFP, black circuit in Fig. A below), which is homologous to the mammalian basal ganglia-thalamo-cortical circuits  (Fig. B below).  We are trying to understand how the AFP influences the song motor pathway to improve song structure using electrophysiological, pharmacologial, and optogenetic approaches.