Presentation

Friederike Contier¹, Melissa Höger¹, Milena Rabovsky¹; ¹University of Potsdam, Germany

The P600 event-related component is elicited by a wide range of anomalies during sentence comprehension, such as grammatical and semantic violations, structural ambiguities, and even spelling errors, and remains important for neurocognitive models of language comprehension (e.g., Kuperberg, 2021, Top. Cogn. Sci.). A recent hypothesis proposes that the P600, similar to the earlier domain-general P3, reflects phasic norepinephrine (NE) release from the locus coeruleus (LC) to salient stimuli that need selective attention and behavioral adaptation (e.g., Bornkessel-Schlesewsky & Schlesewsky, 2019, Front. Psychol.). Importantly, phasic release of norepinephrine plays an important role in explicit memory formation since the LC innervates limbic structures that are involved in consolidation of long-term memory (Sara, 2009, Nat. Rev. Neurosci.). If these late positivities indeed reflect phasic norepinephrine release from the LC, an enhanced amplitude should thus lead to stronger explicit memory formation. Indeed, the P3 amplitude to a stimulus is predictive of later recall of that stimulus (e.g., Karis et al., 1984, Cogn. Psychol.). This ERP study investigates whether the P600 amplitude similarly relates to explicit memory formation. In the encoding phase, participants (N = 38) will read 240 sentences word by word including a critical target noun that is either morphosyntactically violated (incorrect article), semantically deviant, or correct and semantically fitting. Within this task, we expect that both morphysyntactic and semantic violations will elicit larger amplitudes than controls between 600-900 ms relative to target word onsets at parietal sites (P600 effect). In a subsequent word recognition task, participants will judge whether a particular word (seen target vs unseen word) appeared in a sentence during the encoding phase or not (Y/N) and how certain they are of their answer (likert scale). Seen targets should be more likely to be recognized than unseen words. Crucially, within seen targets, recognition should be positively predicted by the P600. That is, both recognition accuracy and certainty should be better for words that elicited larger P600 amplitudes during the encoding phase. We will additionally explore whether this is the case for both semantic and morphosyntactic violations. We will use linear/logistic mixed effects models, taking into account that the effect of interest might vary across participants and/or items. Data collection will start in June and we expect to present preliminary results at the 2022 SNL meeting. Since the explicit memory effect is a prediction of a specific neurobiological theory of the P600, observing this effect would further link the component to the LC/NE system and the P3, possibly suggesting a more domain-general nature of the component. In addition, it would suggest down-stream consequences in that the brain response that deals with salient and anomalous aspects in the linguistic input in the moment will also be involved in keeping this event available for later recall.

Topic Areas: Control, Selection, and Executive Processes, Meaning: Lexical Semantics