Neural signatures of semantic anticipation in sentence comprehension
It has been proposed that the human brain is a proactive processor. Rather than passively receiving information, it is seen as continuously attempting to predict what will happen next. In the domain of language, evidence supports that people predict different linguistic aspects of the sentences they...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/673778 |
| Acceso en línea: | http://hdl.handle.net/10803/673778 |
| Access Level: | acceso abierto |
| Palabra clave: | Comprensió Comprensión Comprehension Semàntica Semántica Semantics Comunicació oral Comunicación oral Oral communication Malaltia de Parkinson Enfermedad de Parkinson Parkinson's disease Psicofisiologia Psicofisiología Psychophysiology Ciències de la Salut 159.9 |
| Sumario: | It has been proposed that the human brain is a proactive processor. Rather than passively receiving information, it is seen as continuously attempting to predict what will happen next. In the domain of language, evidence supports that people predict different linguistic aspects of the sentences they read or hear, such as the meaning of upcoming words. However, the brain mechanisms that sustain the formulation of these predictions and the subsequent generation of semantic expectations during comprehension remain largely unknown. The current dissertation investigated neural correlates associated with anticipatory processing during sentence comprehension throughout four electrophysiological (EEG) studies. To this end, a novel experimental paradigm was designed, which allowed to capture two theoretically distinct temporal phases in from the lens of predictive processing: the anticipatory and the processing phase of (un)predicted words. The first three studies focused on exploring the mechanisms involved in the anticipatory phase in healthy young adult population. The first study described signatures of anticipatory processing associated with semantic prediction in speech comprehension. Specifically, in the interval between the context and the final word of a sentence, a sustained negative potential developed, with a larger amplitude at increasing levels of semantic expectancy. The second study replicated this anticipatory index in reading comprehension, establishing generality across input modalities. Furthermore, it demonstrated that differences emerged earlier and progressively over the course of sentence processing. Lastly, the third study revealed that contextually expected words were also preceded by a transient alpha power decrease, common in both modalities of comprehension. Based on their psychophysiological features, the observed neural signatures are consistent with the online recruitment of anticipatory mechanisms tied to semantic prediction during sentence comprehension. Finally, the fourth study evaluated the status of the previously described brain signatures in adults with Parkinson’s disease (PD) with dopaminergic compensation), given that this condition entails cognitive deficits that might negatively affect the proper use of sentential contexts. Relative to the control group, the group of PD patients exhibited normal correlates of semantic anticipation and semantic processing. On the other hand, semantic processing was altered in a subgroup of PD patients with mild cognitive impairment (PD-MCI), compared to patients without MCI. Specifically, there was a significant prolongation in the semantic processing of words that did not match the contextual expectation. Lastly, for all PD patients, worse verbal fluency scores correlated with alterations in semantic anticipation and processing, suggesting that, in PD, deficits in mechanisms that rely on brain networks in the temporal lobe might hinder predictive language processing during sentence comprehension. |
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