Shedding Light on How the Brain Controls the Emotion in Your Voice
By Jeffrey Markowitz
How do we convey information when we speak to one another? There is what we say–the literal content of what is spoken–but there is also how we say it. The loudness of a sound can turn a gentle nudge into an intimidating command. The modulation of our voices is critical in navigating a wide variety of social contexts, raising the question of whether there is a specific part of our brain that is dedicated to this task.
A mouse broadcasting its emotions through ultra-sonic vocalizations. Image credit: Jingyi Chen.
In work recently published in Nature, Jingyi Chen and colleagues studied how mice control the volume and duration of their high-pitched whistles called ultra-sonic-vocalizations (USVs). USVs are an important way for mice to communicate with each other. For instance, in the presence of a female, male mice will make their USVs louder and longer. Using a combination of experimental tools and machine learning, Chen et al identified a specific set of neurons in the lateral preoptic area, a region of the hypothalamus, that regulate the socially-aware tuning of mouse vocalizations. Direct stimulation of these cells could generate the full gamut of USVs produced by male mice; while stimulation of their downstream targets produced only long and loud USVs–in essence, crude vocalizations without social affect. This shows that a specific subset of cells in the hypothalamus, a structure that plays a key role in regulating many of the essential features of emotional behavior, also directly control the emotional valence of vocalizations. This work may pave the way for the discovery of similar cells in humans, advancing our understanding of social disorders such as autism and depression.
Jeffrey Markowitz is a postdoctoral fellow in the Department of Neurobiology at Harvard Medical School.
Learn more in the original research article:
Flexible scaling and persistence of social vocal communication.
Chen J, Markowitz JE, Lilascharoen V, Taylor S, Sheurpukdi P, Keller JA, Jensen JR, Lim BK, Datta SR, Stowers L. Nature. 2021 May;593(7857):108-113. doi: 10.1038/s41586-021-03403-8. Epub 2021 Mar 31.PMID: 33790464