Neural desynchronization during speech planning of phrase composition

Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Marco C. H. Lai¹, Ellie Abrams¹, Sherine Bou Dargham², Jacqui Fallon³, Ebony Goldman⁴, Miriam Hauptman⁵, Alicia Parrish¹, Sarah F. Phillips^1,6, Alejandra Reinoso⁷, Liina Pylkkänen^1,2; ¹New York University, ²New York University Abu Dhabi, ³University of Colorado Boulder, ⁴City University of New York Graduate Center, ⁵Johns Hopkins University, ⁶Georgetown University Medical Center, ⁷Northwestern University

Previous research on language production has observed power desynchronization during single-word speech planning (Ala-Salomäki et al., 2021; Piai et al., 2015). Furthermore, the Information via Desynchronization Hypothesis suggests that increased power desynchronization reflects the amount of information encoded within the neural population (Hanslmayr et al., 2012). The present study used a picture naming task with magnetoencephalography (MEG) to investigate (1) whether neural desynchronization is modulated by the amount of information during speech planning and (2) how information is integrated when speakers plan to produce phrases. In the experiment, participants described a picture using either an adjective-noun phrase (e.g., “green house”) for phrase naming or a noun (e.g., “house”) for word naming. Time-frequency analyses of MEG data from 20 adult participants (mean age: 26.3 years) revealed that, compared to word naming, phrase naming showed greater theta (4–7 Hz) power desynchronization in the left anterior temporal lobe (ATL) and precuneus approximately -400 to -200 ms before speech onset. Additionally, greater beta (15–30 Hz) power desynchronization was observed for phrase naming in the bilateral posterior temporal lobes around -250 ms before speech onset. Representational similarity analysis further showed that theta power desynchronization in the left ATL is associated with a conceptual combination process—an additive operation that combines the semantic vectors of adjectives and nouns—during phrase naming. Our findings indicate that increased power desynchronization corresponds to a greater amount of information processed during speech planning. Moreover, theta power desynchronization in the left ATL plays a crucial role in the conceptual combination of simple phrases.

Topic Area: LONG-TERM MEMORY: Semantic