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Songbirds can change their song through a specific manipulation of brain activity patterns. This was discovered by Sanne Moorman, cognitive neurobiologist at Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ. ‘One of the changes we observed was that birds repeated parts of their song. After normalisation of the brain activity, the original song was restored: they sang their old song again.’ According to Moorman, this result can help improve speech problems, such as stuttering, in humans. Her findings were published in the scientific journal on 10 May.

Moorman points out that there are parallels between the brain mechanisms for bird song and human speech. ‘As a result, we expect that a similar recovery of brain activity patterns, as we found in our songbirds, may also help to improve speech problems in humans.’

Continuing to speak and pace of speech

Stuttering is not only characterised by the repetition of words or parts of words. Moorman: ‘Another characteristic is that after a hesitation, it is possible to continue speaking. And that the pace of speech also is less fluent.’ The Utrecht researcher explains that repetitions in stuttering also occur in the animal models. ‘The zebra finches in our study similarly repeated some song notes after the pharmacological manipulation. So they stuttered.’ However, the other symptoms of stuttering had never been observed in animals before. ‘But we found that after the repetition, stuttering, our zebra finches continued to sing. The pace of the notes, and the pauses, also appeared to have become more irregular.’ Such a stutter phenotype, which resembles human stuttering in so many facets, has never been found in animals before.

Researchers will be able to refine their search for pharmacological therapies for speech disorders.

Pattern of brain activity

Is the solution to human stuttering now up for grabs? Moorman says that that stage has not yet been reached. ‘Humans and zebra finches both have what is known as the cortico-striatal circuit in the brain. This brain circuit is important to both songbirds and humans for learned movements, such as singing in birds and speech in humans. A disorder in this circuit can lead to movement disorders, such as stuttering or Parkinson's disease. What we have now discovered through our research is that the pattern of brain activity in this circuit is crucial for changing behaviour, more than the absolute degree of brain activity. We expect that a normalisation of the activity pattern in the cortico-striatal circuit in humans, as in zebra finches, may lead to a change in speech. The information from our study will enable researchers to refine their search for pharmacological therapies for speech disorders.’

Sanne Moorman conducted this research project in collaboration with colleagues from .