Neural correlates of vocal learning in songbirds and humans: cross-species fMRI studies into individual differences
Vocal learning is a trait shared by songbirds and humans. It is also a trait that is restricted by the brain rather than by a species' vocal apparatus. In this dissertation, functional MRI is employed in both species in order to explore potential common neural mechanisms underlying the ability to develop species-specific vocalizations through memorization and imitation of an adult model. Furthermore, the restrictions imposed on this ability by sensitive periods for vocal learning, which have been hypothesized for both songbirds and humans, are explored.
- Anne Marie van der Kant
- 28 January 2015
- Full text in Leiden University Repository
In zebra finches, a songbird species that learns one specific song, neural responses to songs learned during development were compared to neural responses to songs that were familiar, but not learned for production. In human adults, who possess a language system too extensive and complex to test in a single experiment, neural responses were recorded before, during and after learning an artificial grammar, comparing a grammar with and without learnable regularities in the form of non-adjacent dependencies.
The results of these studies provide additional insight into the neural correlates of vocal learning and the processing of learned stimuli. In both humans and zebra finches, vocal learning and processing of learned vocalizations and their structure induce selective activation in brain regions associated with auditory processing and abstraction of vocalizations. Furthermore, this selective activation is related to learning outcomes both in humans and in zebra finches. In humans, structural and functional connectivity within the network processing human language are related to (artificial) grammar learning capacity.