Research master thesis | Psychology (research) (MSc)
open access
2024-08-31T00:00:00Z
Prior studies have shown ambiguous results concerning the question if and how cognitive performance and neurophysiological markers change under the influence of weightlessness. Additional research...Show morePrior studies have shown ambiguous results concerning the question if and how cognitive performance and neurophysiological markers change under the influence of weightlessness. Additional research is necessary to confirm effects and shed light on experimental and interindividual differences and those related to various mechanisms underlying cognitive processes. This study aimed to assess the influence of microgravity on the neurocognitive marker P3 during parabolic flight. METHODS: Participants were trained to perform a brain-computer interface (BCI) task, which included a visual oddball paradigm task. Nine participants performed this task during parabolic flight. Statistic analyses assessed the amplitude and latency of the P3 event-related potential (ERP). RESULTS: Results revealed no significant differences for P3 Amplitude nor Latency in the 0G condition versus the 1G condition. The amplitude for oddball stimuli was significantly higher than the amplitude for standard stimuli in both 1G and 0G. CONCLUSION: There needs to be greater consensus and understanding concerning the effects of microgravity on cognitive performance and ERPs. The data presented here does not verify that short bouts of microgravity could enhance nor diminish neuro-behavioral performance. It does confirm that the visual-based oddball paradigm is feasible in microgravity conditions.Show less
Research master thesis | Linguistics (research) (MA)
under embargo until 2025-07-31
2025-07-31T00:00:00Z
While multiple models of language production exist, it remains difficult to find conclusive evidence for one or the other model. The present study is one of the first to incorporate both behavioral...Show moreWhile multiple models of language production exist, it remains difficult to find conclusive evidence for one or the other model. The present study is one of the first to incorporate both behavioral data and EEG data in a native Dutch noun phrase production task to investigate the processing of grammatical gender. We used a picture-word interference paradigm in which speakers had to name a picture while being distracted by a superimposed word. The distractors were manipulated for grammatical gender congruency with and semantic relatedness to the picture names. In separate blocks, participants had to produce either bare nouns, or determiner noun constructions. We found a robust effect of the semantic relatedness effect in the behavioral data, in which targets belonging to the same semantic category as the distractor were named significantly later than unrelated targets. The EEG data on the semantic relatedness effect were less clear, possibly due to opposing ERP components in (partly) overlapping time windows. More importantly, we replicated the gender congruency effect in reaction times, showing that naming latencies were longer for gender-incongruent trials than for congruent trials. This behavioral effect disappeared in bare noun naming. The EEG data showed similar results, in which a more positive peak was found between 385-585 milliseconds for incongruent than for congruent trials, again only in the determiner noun block. The result seems to indicate a P300 effect rather than the expected enhanced N400, suggesting higher conflict resolution processes for incongruent trials. The absence of the gender effect in bare noun naming in both data types suggests that grammatical gender is not automatically accessed or selected in Dutch noun (phrase) production. This in turn has implications for speech production models.Show less
Intrasentential code-switching requires cognitive control in production (Verreyt et al., 2016) as well as comprehension (Adler et al., under review). The first language needs to be inhibited as...Show moreIntrasentential code-switching requires cognitive control in production (Verreyt et al., 2016) as well as comprehension (Adler et al., under review). The first language needs to be inhibited as soon as the second languages is encountered. The neurological system that is associated with cognitive control may stay active for a while after being triggered. Cognitive control is used for any (cognitive) task that requires inhibition, selected attention or decision making. An example of such a task is the Flanker task, in which a participant has to determine the direction of an arrow surrounded by four (congruent or incongruent) distractors. In general, when the arrows all point in the same direction (congruent condition) participants have a shorter reaction time than when the surrounding arrows point in the opposite direction of the target arrow (incongruent condition). The effect of code-switches on Flanker trials has been studied behaviourally. These studies show that processing a code-switch has a positive effect on the reaction time on the incongruent Flanker trials. In this study, we support previous behavioural findings with an electrophysiological investigation of the effect of code-switch detection on cognitive control. We recorded the EEG of 34 participants while they alternated between reading sentences (with and without code-switches) and Flanker trials. In the analysis of the EEG, we were specifically interested in the P300 component, which is associated with shifts in attention. The P300 amplitude is higher when more cognitive control is required (Neuhaus et al., 2010). Since incongruent Flanker trials require more cognitive control than congruent trials, the classic Flanker effect is that the incongruent trials produce a larger P300. However, after being activated by a code-switch, if the cognitive control mechanism indeed stays active for a while, the P300 amplitude of an incongruent Flanker after a code-switch would be lower than one after a sentence without a code-switch. The mean ERP amplitudes were analysed with a 4-way repeated measures ANOVA. Significant interactions were found between sentence type and congruency. There was a significantly larger P300 in the congruent condition than in the incongruent condition, but only when the preceding sentence did not have a code-switch. The P300 was significantly larger after sentences with a code-switch than after sentences without a code-switch, but only in the incongruent condition. There was no effect of sentence type in the congruent condition. These results provide electrophysiological support for previous findings by Adler et al., (under review).Show less
