Search Abstracts | Symposia | Slide Sessions | Poster Sessions | Lightning Talks

Catecholaminergic modulation of garden-path sentence processing: An ERP study with methylphenidate

Poster B45 in Poster Session B, Tuesday, October 24, 3:30 - 5:15 pm CEST, Espace Vieux-Port

Yingying Tan1,2, Ashley Lewis2,3, Iris Schmits2, Robbert-Jan Verkes4, Roshan Cools3,4, Peter Hagoort2,4; 1Shanghai International Studies University, Linguistics Department, Shanghai, China, 2Max Planck Institute for Psycholinguistics, Neurobiology of Language Department, Nijmegen, the Netherlands., 3Radboud University, Donders Institute for Brain, Cognition and Behaviour, Center for Cognitive Neuroimaging, Nijmegen, the Netherlands, 4Radboud University Medical Center, Department of Psychiatry, Nijmegen, the Netherlands

The Catecholaminergic (CA) neurotransmitter system located primarily in the prefrontal cortex and basal ganglia of the human brain play a crucial role in cognitive control[1]. CA levels have been implicated in semantic unification during sentence processing[2]. The link between CA and syntactic unification is yet to be explored. In this study, by combining electroencephalography (EEG) and neuropharmacology, we examined how a CA stimulant (methylphenidate – MPH) impacted the processing of garden-path sentences. Garden-path sentences provide an excellent model system for examining the influence of CA levels on syntactic unification processes. Forty healthy participants were tested in two experimental sessions, one in which they ingested 20 mg MPH and the other a placebo. This was a within-participant, double-blind, randomized, crossover design. In every session participants read 40 sentences in each of three conditions (ambiguous, unambiguous, control; Example below). In the ambiguous condition, it is well established that readers initially treat the 3rd noun phrase (NP; “guitarist”) as an instance of NP-coordination, but have to revise their parse upon reading the disambiguating target word (TW; “packed”), which clearly requires a S-coordination reading. In the unambiguous condition, a comma earlier in the sentence helps avoid the garden-path. The control condition includes no ambiguity. Participants’ brain responses were recorded from 28 EEG electrodes. Mixed-effects models were used for statistical testing on the standardly preprocessed data. Example Ambiguous: The fan attacked the drummer and the guitarist packed the instruments up. Unambiguous: The fan attacked the drummer, and the guitarist packed the instruments up. Control: The fan attacked the drummer and the guitarist with a knife in his hand. At the TW, we replicated a P600 effect for the comparison between the ambiguous and control conditions (t = 2.23)[3], while there was no difference between the unambiguous and control condition. Both the ambiguous and the unambiguous conditions elicited a more pronounced negativity in the late N400 time window (tambiguous = -2.95; tunambigouous = -2.06). These results suggest that our Dutch participants may not immediately benefit from punctation, but the comma does appear to have an impact on later processes of revision. The only influence of the drug was observed in the early N400 time window. After taking MPH, participants showed a more pronounced negativity in the unambiguous than in the control condition, regardless of the order of drug administration (t = -2.23). On the other hand, a more pronounced negativity was observed for the ambiguous than control condition, only when the drug was administered in the first testing session (t = -2.02). There was no ambiguity effect in this time window under placebo or when MPH was administered in the second testing session. Our results demonstrate a clear neuropharmacological influence on language processing. The locus of our MPH effect was restricted to early, more automatic processing and we did not find any evidence for an influence of CA levels on later, more controlled processes of syntactic unification. [1] Westbrook et al., 2021. TiCS. [2] Tan, et al., (2020). Cerebral Cortex. [3] Kerkhofs et al., (2008). BrainResearch.

Topic Areas: Syntax and Combinatorial Semantics, Control, Selection, and Executive Processes

SNL Account Login

Forgot Password?
Create an Account