Biology subjects

Hsu, T.-Y.

Publications and source records attributed to Hsu, T.-Y..

8 recordsLinked to original sources

bioRxiv2026

A multiverse analysis of stomach-brain coupling in humans

The gastric-brain axis is a burgeoning field of neuroscience; however, inferences from neuroimaging research are often constrained by the high dimensionality of methodological choices potentially leading to disparate outcomes. This study addresses such concerns by performing a multiverse analysis of gastric-brain coupling in humans. We systematically evaluated 1,728 unique analytic pipelines using electroencephalography (EEG) and electrogastrography (EGG) data to quantify the robustness of observed gastric-brain coupling. Our results reveal that whilst analytic decisions influence the magnitude of observed coupling, at the group level the phenomenon remains relatively robust across the parameter space. High inter-individual variance can, however, be observed. Coupling was observed in the alpha, theta, and beta bands, with the latter two bands showing robust coupling across the largest number of electrodes. Robust coupling across frequency bands was primarily seen in medial electrodes, with some left lateral coupling also observed. Overall, these findings suggest that gastric-brain coupling is likely to be a robust physiological feature in healthy participants, providing a stable foundation for future studies.

neuroscience↗

bioRxiv2026

Comparing aperiodic brain activity between eyes open rest and dynamic visual input using magnetoencephalography

Inscapes is a low demand abstract animation used as an alternative to eyes open rest in neuroimaging studies, particularly with pediatric and clinical populations prone to head motion. Although prior work has established that functional connectivity patterns during Inscapes closely resemble those during rest, no study has examined whether the two conditions differ in aperiodic neural activity, a broadband feature of the power spectrum linked to excitation/inhibition balance. Here we used magnetoencephalography (MEG) in 54 healthy adults to compare spectrally parameterised aperiodic and periodic measures between eyes open rest and Inscapes viewing (visual component only, without audio). At the sensor level, both the aperiodic exponent and offset were significantly higher during rest than during Inscapes across widespread frontoparietal and occipital distributions in both magnetometers and gradiometers. Source level analyses at both the parcellation and vertex levels largely supported these patterns. The pericalcarine cortex was a notable exception, where both aperiodic measures were higher during Inscapes than during rest, indicating a regionally specific reversal in primary visual cortex. These results demonstrate that Inscapes and eyes open rest produce distinct aperiodic spectral profiles, indicating that the two conditions are not interchangeable for analyses involving broadband spectral dynamics or excitation/inhibition balance estimation.

neuroscience↗

bioRxiv2025

Neural correlates of transitions between internal and external cognitive domains

Human cognition involves continuous transitions between processing information guided by the external world and engaging with internally-generated thoughts, yet research has predominantly investigated switching based on external rules. We therefore examined neural mechanisms underlying external and internal domain switching using independent groups of EEG (N=46) and fMRI (N=60) in a colour judgement task requiring evaluations based on either colour similarity (external domain) or colour preference (internal domain) through switching on a trial-by-trial basis. ERPs revealed amplitude differences between the two judgements as well as switching and repeated trials. EEG analysis revealed a sustained neural differentiation between switch and repeated trials, specifically during similarity judgements, with effects lasting from early time points through the entire trial duration. fMRI showed similarity judgements engaged visual and motor regions during switching, while preference judgements showed minimal subcortical activation for repeated trials. These findings demonstrate that external and internal cognitive domain switching effects are asymmetrical. These findings provide the first temporal and spatial neural characterisation of domain switching between processing information guided by the external world and internally-generated thoughts, indicating that shifting between internal and external domains involves mechanisms distinct from traditional external rule-switching paradigms.

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bioRxiv2023

Relationship Between the P300 and Sequence Knowledge in a Changing Environment

The P300 amplitude has been linked to the processing of uncertain events. Studies have assumed that knowledge extracted from sequences of events corresponds to event probability. The relationship between the P300 and event uncertainty has been studied using the model-based analysis, in which the subjective expectancy of event probability is modeled and examined by using a quantity called "surprise." However, other types of sequence knowledge exist, such as event transition probabilities, which comprises both event repetitions and event alterations. Whether the state of the environment affects the encoded sequence knowledge is not fully understood, and the type of sequence knowledge, event probability or event transition probability, that is encoded in the brain in a changing environment remains unknown. We determined whether fluctuations in the P300 are better explained by surprise based on a model of event probability or by surprise based on a model of event transition probability. Participants completed a two-choice response task in which a binary sequence was generated from a hidden Markov model. Reaction times indicated that behavior changed depending on the event transitions. The model-based analysis revealed that trial-by-trial P300 was better explained by surprise based on a model of event transition probability. Our results suggest that humans use the sequence knowledge of event transitions in a changing environment.

neuroscience↗

bioRxiv2022

Prefrontal-Parietal-cTBS effects on metacognitive awareness: real or illusory?

BackgroundNeuroimaging and lesion studies suggested that the dorsolateral prefrontal and posterior parietal cortices mediate visual metacognitive awareness. The causal evidence provided by non-invasive brain stimulation, however, is inconsistent. Objective/HypothesisHere we revisit a major figure discrimination experiment adding a new Kanizsa figure task trying to resolve whether bilateral continuous theta-burst transcranial magnetic stimulation (cTBS) over these regions affects perceptual metacognition. Specifically, we tested whether subjective visibility ratings and/or metacognitive efficiency are lower when cTBS is applied to these two regions in comparison to an active control region. MethodsA within-subjects design including three sessions spaced by one-week intervals was implemented. In each session, every participant was administered bilateral cTBS to either prefrontal, control or parietal cortices. Two concurrent tasks were performed, a real and an illusory figure task, stabilising objective performance with use of an adaptive staircase procedure. ResultsWhen performing the replicated task, cTBS was found insufficient to disrupt neither visibility ratings nor metacognitive efficiency. However, with use of Kanizsa style illusory figures, cTBS over the dorsolateral prefrontal, but not over the posterior parietal cortex, was observed to significantly diminish metacognitive efficiency. Conclusion(s)Real and illusory figure tasks demonstrated different cTBS effects. A possible explanation is the involvement of the prefrontal cortex in the creation of expectations, which is necessary for efficient metacognition. Failure to replicate previous findings for the real figure task, however, cannot be said to support, conclusively, the notion that these brain regions have a causal role in metacognitive awareness. This inconsistent finding may result from certain limitations of our study, thereby suggesting the need for yet further investigation.

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bioRxiv2021

Intrinsic neural activity predisposes susceptibility to a body illusion

Susceptibility to the rubber hand illusion (RHI) varies. Thus far, however, there is no consensus as regards how to explain this variation. Previous studies, focused on the role of multisensory integration, have searched for neural correlates of the illusion. Those studies, however, have failed to identify a sufficient set of functionally specific neural correlates. An alternative explanation of the illusion is that it results from demand characteristics, chiefly variability in the disposition to respond to imaginative suggestion: the degree to which intrinsic neural activity allows for a blurring of boundaries between self and external objects. Some evidence suggests that frontal power is one means of tracking neural instantiations of self; therefore, we hypothesized that the higher the frontal power during eyes-closed resting state, the more stable the self. As a corollary, we infer that the more stable the self, the less susceptible are participants to a blurring of boundaries--to feeling that the rubber hand belongs to them. Indeed, we found that frontal amplitude oscillations negatively correlate with susceptibility. Moreover, since and {delta} oscillations seem to be associated in pathological states that allow for a blurring of boundaries between self and external objects, we conjectured that the high frontal power observed in low-RHI participants is modulated by {delta} frequency oscillations. Indeed, we found this to be the case. Based on our findings we propose that the two explanatory frameworks might be complementary: that is, the neural correlates of multisensory integration might be necessary for the RHI, but a sufficient explanation requires investigation of variable intrinsic neural activity that acts to modulate how the brain responds to incompatible sensory stimuli. Highlights~Intrinsic frontal power negatively correlates with susceptibility to the RHI. ~Intrinsic power modulated by {delta} oscillations varies with susceptibility to the RHI. ~Sufficient explanation of RHI requires understanding of intrinsic neural dispositions that regulate the boundary between self and the external world.

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bioRxiv2019

Temporal preparation and short-term temporal memory in depression

Patient suffering of Major Depressive Disorder (MDD) often complain that subjective time seems to drag with respect to physical time. This may point towards a generalized dysfunction of temporal processing in MDD. In the present study, we investigated temporal preparation in MDD. \"Temporal preparation\" refers to an increased readiness to act before an expected event; consequently, reaction time should be reduced. MDD patients and age-matched controls were required to make a saccadic eye movement between a central and an eccentric visual target after a variable duration preparatory period. We found that MDD patients produced a larger number of premature saccades, saccades initiated prior to the appearance of the expected stimulus. These saccades were not temporally controlled; instead, they seemed to reflect increased oculomotor impulsivity. In contrast, the latency of visually-guided saccades was strongly influenced by temporal preparation in controls; significantly less so, in MDD patients. This observed reduced temporal preparation in MDD was associated with a faster decay of short-term temporal memory. Moreover, in patients producing a lot of premature responses, temporal preparation to early imperative stimuli was increased. A reduction in premature saccades, however, was associated with reduced temporal preparation to late imperative stimuli.\n\nIn conclusion, reduced temporal preparation and short-term temporal memory in the oculomotor domain supports the hypothesis that temporal processing was altered in MDD patients. These observed deficits could reflect other underlying aspects of abnormal time experience in MDD.

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bioRxiv2019

Intrinsic activity temporal structure reactivity to behavioural state change is correlated with depressive rumination

The brains intrinsic activity plays a fundamental role in its function. In normal conditions this activity is responsive to behavioural context, changing as an individual switches between directed tasks and task-free conditions. A key feature of such changes is the movement of the brain between corresponding critical and sub-critical states, with these dynamics supporting efficient cognitive processing. Breakdowns in processing efficiency can occur, however, in brain disorders such as depression. It was therefore hypothesised that depressive symptoms would be related to reduced intrinsic activity responsiveness to changes in behavioural state. This was tested in a mixed group of major depressive disorder patients (n = 26) and healthy participants (n = 37) by measuring intrinsic EEG activity temporal structure, quantified with detrended fluctuation analysis (DFA), in eyes-closed and eyes-open task-free states and contrasting between the conditions. The degree to which DFA values changed between the states was found to be negatively correlated with depressive symptoms. DFA values did not differ between states at all in those with high symptom levels, meaning that the brain remained in a less flexible sub-critical condition. This sub-critical condition in the eyes-closed state was further found to correlate with levels of maladaptive rumination. This may reflect a general cognitive inflexibility resulting from a lack in neural activity reactivity that may predispose people to overly engage in self-directed attention. These results provide an initial link between intrinsic activity reactivity and psychological features found in psychiatric disorders.

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