Basal ganglia: Bursting with song

Area of Science:

• Neuroscience
• Animal Behavior
• Bioacoustics

Background:

• Mature zebra finch songs are highly stable and repetitive, a state known as song crystallization.
• The basal ganglia play a crucial role in motor control, including vocal production in songbirds.

Purpose of the Study:

• To investigate whether sustained artificial stimulation of cortical inputs to the basal ganglia can induce lasting changes in crystallized zebra finch songs.
• To explore the potential for inducing vocal plasticity and stuttering-like phenomena through targeted neural manipulation.

Main Methods:

• Chronic, pharmacologically induced bursting stimulation of cortical neurons projecting to the basal ganglia in adult male zebra finches.
• Acoustic analysis of song features before, during, and after the stimulation period to quantify changes in vocalizations.
• Behavioral observation to identify any emergent phenomena resembling human speech disorders.

Main Results:

• Sustained bursting stimulation led to cumulative and lasting alterations in multiple song features, disrupting the established crystallized song structure.
• Specific vocal changes were observed, including increased variability and temporal disruptions, some of which were reminiscent of human stuttering.
• The effects persisted long after the stimulation was ceased, indicating a form of vocal learning or adaptation.

Conclusions:

• The basal ganglia network, despite song crystallization, remains capable of undergoing significant and enduring modifications.
• Pharmacological manipulation of specific neural pathways can effectively drive lasting changes in complex learned vocalizations.
• This study provides a model for understanding the neural mechanisms underlying vocal stability and the potential for inducing vocal pathologies like stuttering.