Adapting lexical representaitons by adding new meanings to known words: The role of left pMTG
Poster No:
796
Submission Type:
Abstract Submission
Authors:
Xiaoping Fang1, Charles Perfetti2
Institutions:
1Beijing Language and Culture University, Beijing, China, 2University of Pittsburgh, Pittsburgh, PA
First Author:
Co-Author:
Introduction:
Associating new meanings with existing words is a crucial method for expanding lexical knowledge at both the individual and population levels (Brochhagen et al., 2024; Ramiro et al., 2019). However, lexical learning studies have primarily focused on the acquisition of novel words, leaving the mechanisms underlying new-meaning learning unclear (e.g., Fang et al., 2017; Rodd et al., 2012). The left posterior middle temporal gyrus (pMTG) is essential for representing form-meaning mappings (e.g., Hickok & Poeppel, 2007). This same brain region is also implicated in creating form-meaning mappings when novel words are learned (e.g., Takashima et al., 2014; Takashima et al., 2017). Building on this, the current study examines the role of the left pMTG in binding new meanings to known words.
Methods:
Participants learned new action meanings (e.g., "lifting with one hand," "walking backwards") for both known words (e.g., "cloud") and novel words (e.g., "bropt") over a four-day learning program. To control for the effect of mere exposure, we included exposure controls for both learning conditions. On Day 4, participants completed two tasks on the studied words while brain activity was recorded using MEG (Elekta Neuromag Vector View 306 Channel System): (1) meaning jusgment, in which participants categorized the new meanings (e.g., leg or hand movement), and (2) Letter Judgment, where participants determined whether a specific letter appeared in a word (e.g., "Is there an 'i' in 'cloud'?").
Results:
Participants achieved high learning performance on both the cued-recall (4.96 out of 5) and recognition tests (98%) on Day 4, indicating that the studied words and their new meanings were well learned. Behavioral data from the MEG tasks revealed that, in both the meaning judgment and letter judgment tasks, participants were slightly more accurate in making judgments on known words than on novel words (β = 1.51, SE = 0.66, z = 2.29, p = .022).
In the MEG data, we focused on source activation in the left posterior middle temporal gyrus (pMTG) and other brain areas relevant to processing the action meanings presented (Binder & Desai, 2011; Papeo et al., 2015). Although not statistically significant, there was a trend of stronger activation for novel words with meanings compared to exposure controls in the left pMTG. Additionally, regardless of the task requirement, stronger source activation for novel words with action meanings, compared to exposure controls, was observed in the left MT+, a brain region sensitive to visual motion. For known words, the inferior frontal gyrus (IFG, BA44), lateral precentral gyrus, and left pMTG, but not the left MT+, were more engaged during the meaning judgment task for known words with new action meanings compared to exposure controls. However, when participants performed a meaning-unrelated letter detection task, activation was reduced for words that had been paired with new meanings.
In the MEG data, we focused on source activation in the left posterior middle temporal gyrus (pMTG) and other brain areas relevant to processing the action meanings presented (Binder & Desai, 2011; Papeo et al., 2015). Although not statistically significant, there was a trend of stronger activation for novel words with meanings compared to exposure controls in the left pMTG. Additionally, regardless of the task requirement, stronger source activation for novel words with action meanings, compared to exposure controls, was observed in the left MT+, a brain region sensitive to visual motion. For known words, the inferior frontal gyrus (IFG, BA44), lateral precentral gyrus, and left pMTG, but not the left MT+, were more engaged during the meaning judgment task for known words with new action meanings compared to exposure controls. However, when participants performed a meaning-unrelated letter detection task, activation was reduced for words that had been paired with new meanings.
·Figure 1. Source activation in the meaning judgment task.
·Figure 2. Source activation in the letter judgment task.
Conclusions:
Overall, the MEG findings suggest that the new meanings of both novel and known words are processed through different parts of the sensorimotor circuits. The left pMTG was more consistently involved in the learning of new meanings for known words than for novel words. Additionally, while source activation for novel words appears unaffected by the task, the processing of new meanings for known words is modulated by task demands. These findings suggest that the left pMTG plays a role in binding new meanings to previously known words, possibly by interacting with neocortical areas involved in the more specific representation of new meanings.
Language:
Language Acquisition 1
Language Comprehension and Semantics
Learning and Memory:
Learning and Memory Other
Modeling and Analysis Methods:
EEG/MEG Modeling and Analysis 2
Keywords:
Language
Learning
MEG
1|2Indicates the priority used for review
Abstract Information
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Provide references using APA citation style.
Brochhagen, T., Boleda, G., Gualdoni, E., & Xu, Y. (2023). From language development to language evolution: A unified view of human lexical creativity. Science, 381(6656), 431–436. https://doi.org/10.1126/science.ade7981
Fang, X., Perfetti, C., & Stafura, J. (2017). Learning new meanings for known words: Biphasic effects of prior knowledge. Language Cognition and Neuroscience, 32(5), 637–649. https://doi.org/10.1080/23273798.2016.1252050
Hickok, G., & Poeppel, D. (2007). The cortical organization of speech processing. Nature Reviews Neuroscience, 8(5), 393–402. https://doi.org/10.1038/nrn2113
Ramiro, C., Srinivasan, M., Malt, B. C., & Xu, Y. (2018). Algorithms in the historical emergence of word senses. Proceedings of the National Academy of Sciences, 115(10), 2323–2328. https://doi.org/10.1073/pnas.1714730115
Rodd, J. M., Berriman, R., Landau, M., Lee, T., Ho, C., Gaskell, M. G., & Davis, M. H. (2012). Learning new meanings for old words: Effects of semantic relatedness. Mem Cognit, 40(7), 1095–1108. https://doi.org/10.3758/s13421-012-0209-1