Neuroscience: How bird brain cells work in harmony to start singing

The zebra finch’s ability to transition between syllables in its courtship songs is driven by the influence of the thalamus region of the brain and a specific set of neurons in another region of the brain associated with birdsong, according to a paper in Nature. The findings highlight the role of the thalamus in controlling complex behaviour.

The thalamus has been shown to play a central role in generating simple trained movements in animals, as inputs from the thalamus are necessary to string short movements together into longer sequences. Male zebra finches (Taeniopygia guttata) practice singing by copying their father’s song, which consists of a sequence of two to seven syllables, each distinct and behaviourally meaningful. However, the mechanisms underlying the motor commands that generate these sequences are unclear.

Michael Long and colleagues studied how neurons in different brain areas work together to learn and produce these courtship songs. The authors used brain imaging to monitor activity in finch brains while they performed their songs in response to seeing their preferred female partners. The authors also used a stimulation electrode implanted in the brain to administer an electrical current at specific moments during the song. Stimulation of a small structure in the thalamus known as nucleus uvaeformis (Uva) showed that this region connects with a set of nerve cells in the brain region called HVC. These nerve cells become very active just before the start of syllables.

These findings have implications for understanding how complex behaviours are generated from combinations of simpler movements; similar arrangements have also been suggested to coordinate human speech and breathing.