An fMRI Study on Cognitive Conflict and Neural Refractoriness During Phonological Processing
Poster No:
728
Submission Type:
Abstract Submission
Authors:
Zirui Zou1, Manson Cheuk-Man Fong1, Xavreila Sheung-Wa Ng1, Matthew King-Hang Ma1, Fangfei Li1, Cloris Pui-Hang Li1, Ashley Cheuk-Ying Cheung1, Nga-Yan Hui1, William Shiyuan Wang1
Institutions:
1The Hong Kong Polytechnic University, Hong Kong, China
First Author:
Co-Author(s):
Introduction:
Neural mechanisms underlying conflict monitoring and resolution have been extensively studied using visual and non-linguistic paradigms, such as the flanker task and Simon task. However, little is known about conflict processing in phonological tasks. In phonological tasks, the same/different judgment (SDJ) paradigm is widely used, yet differences in neural activity between "different" and "same" responses have been largely overlooked. Specifically, previous studies on stimulus repetition have suggested that two identical stimuli presented in close succession elicit less neural activity than distinct stimuli, a phenomenon known as the "refractory effect." Within the SDJ paradigm, the neural basis of refractory effects in auditory attention and conflict monitoring remains unexplored. Moreover, conflict engages top-down attentional mechanisms, while refractoriness is driven by bottom-up sensory processes. Whether the attention system is modulated by lower-level neural refractoriness remains an open question.
Methods:
The present study aimed to address these gaps by incorporating cognitive conflict and neural refractoriness into a phonological same–different judgment task, through conducting an fMRI experiment with 29 young Hong Kong Cantonese participants (aged 19–30, mean = 23.6, SD = 2.9). The task followed a two-by-two design, with Conflict (high vs. low conflict) and Refractoriness (different vs. same) as factors (Table 1). Participants should judge whether initial consonants are the same or different between a pair of distinct syllables presented in succession (Figure 2). In our design, conflict effects arise from responding to task-relevant features with "same" and "different", while suppressing interference from task-irrelevant features in the syllable pair. High conflict requires suppressing an additional feature compared to low conflict. Refractory effects stem from the repetition of target features, with "same" having higher refractoriness than "different" (see also Figure 1). Our hypotheses were: (1) Conflict-control regions such as the anterior cingulate cortex (ACC) and lateral prefrontal cortex would be sensitive to the degree of conflict; (2) Refractory effects would be present, such that the activation would be smaller for "same" than "different" condition in auditory sensory regions; (3) Conflict effects would interact with refractory effects.
·Stimulus Design and Task Procedure
Results:
For behavioral data, ANOVAs (Table 3, and 4) revealed significant main effects of refractoriness on accuracy and reaction time, while main effects of conflict were non-significant. The interaction between conflict and refractoriness was significant for accuracy. For fMRI data, our whole-brain and region of interest (ROI) analyses (Figure 3 and 4) showed the following results. (1) Cognitive conflict in phonological processing activated conflict-control regions, including the ACC, superior frontal gyrus, and parietal cortex, consistent with previous observations in typical conflict tasks. Notably, low-conflict conditions showed higher activation than high-conflict conditions, potentially reflecting the influences of task difficulty and individual differences. (2) Refractory effects related to auditory attention were found in right occipitotemporal and left middle occipital regions. (3) We identified interaction effects between conflict and refractoriness in the ACC, superior temporal sulcus, and inferior occipital gyrus. ANOVAs in ROI analyses on these regions showed conflict effects were larger in "different" than "same" (see Figure 4), indicating modulations of conflict by refractoriness.
·Behavioral and Neuroimaging Results
Conclusions:
In conclusion, an auditory attention network sensitive to conflict and refractoriness was identified within frontoparietal control-related regions and occipitotemporal sensory regions during phonological processing of consonants. Our results revealed interactions between high-level conflict mechanisms and low-level refractory processes. This research was supported by HKRGC-GRF 15606119 and 15609423.
Higher Cognitive Functions:
Executive Function, Cognitive Control and Decision Making 1
Language:
Speech Perception
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI)
Perception, Attention and Motor Behavior:
Attention: Auditory/Tactile/Motor 2
Perception: Auditory/ Vestibular
Keywords:
FUNCTIONAL MRI
Language
Perception
Other - Cognitive Conflict; Neural Refractoriness; Phonological Processing
1|2Indicates the priority used for review