Premotor cortex uses a compositional neural geometry to plan words
Speech requires precise serial ordering of words and phonemes into novel combinations. To accomplish this, the brain is believed to flexibly prepare utterances before producing them, even allowing pronunciation of never-before spoken words. To discover how neural populations achieve this, intracortical activity from premotor cortex was recorded while two speech neuroprosthesis pilot clinical trial participants attempted to speak factorially-balanced phoneme sequences. During preparation, activity encoded not only the next-phoneme, but multiple upcoming phoneme positions spanning whole words. We found that word-level plans were formed by compositionally combining phoneme representations, a mechanism that may enable efficient planning of novel sequences. When utterances contained more than one word, premotor cortex activity was largely limited to the first word, suggesting that articulatory planning is segmented by higher-order features. Together, these results reveal a compositional, hierarchically-segemented planning geometry, potentially a universal neural strategy for sequence organization across higher levels of language.
Authors
- Maitreyee Wairagkar (ORCID: https://orcid.org/0000-0002-9546-2843)
- Jaimie M. Henderson (ORCID: https://orcid.org/0000-0002-3276-2267)
- Leigh R. Hochberg (ORCID: https://orcid.org/0000-0003-0261-2273)
- Shaul Druckmann
- David M. Brandman (ORCID: https://orcid.org/0000-0003-3224-7019)
- Akansha Singh (ORCID: https://orcid.org/0000-0001-9101-4157)
- Sergey D. Stavisky (ORCID: https://orcid.org/0000-0002-5238-0573)
- Francis R. Willett (ORCID: https://orcid.org/0000-0002-2652-8511)
- Erin M. Kunz (ORCID: https://orcid.org/0009-0003-5246-6937)
- Nicholas S. Card (ORCID: https://orcid.org/0000-0002-6858-268X)
- Nick Hahn
- Carrina Iacobacci
- Benyamin Abramovich Krasa (ORCID: https://orcid.org/0000-0001-8539-5096)
- Foram Kamdar
- Donal Avansino
Institutions
- Allen Institute for Brain Science (US)
- Harvard University (US)
- Neurosciences Institute (US)
- Brown University (US)
- Providence VA Medical Center (US)
- Massachusetts General Hospital (US)
- Center for Neuro-Oncology (US)
- Neurological Surgery (US)
- University of California, Davis (US)
- Stanford University (US)
Publication Details
- Journal
- bioRxiv (Cold Spring Harbor Laboratory)
- Published
- 2026-04-30
- DOI
- https://doi.org/10.64898/2026.04.27.721195
- Primary Topic
- Neurobiology of Language and Bilingualism
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- U.S. Department of Veterans Affairs
- A.P. Giannini Foundation
- Office of Research and Development
- Giannini Foundation of Agricultural Economics
- National Institutes of Health
- Wu Tsai Neurosciences Institute, Stanford University
- National Institute on Deafness and Other Communication Disorders
- National Science Foundation Graduate Research Fellowship Program