Audiovisual integration in the McGurk effect is impervious to music training.

The McGurk effect refers to an audiovisual speech illusion where the discrepant auditory and visual syllables produce a fused percept between the visual and auditory component. However, little is known about how individual differences contribute to the McGurk effect. Here, we examined whether music training experience-which involves audiovisual integration-can modulate the McGurk effect. Seventy-three participants completed the Goldsmiths Musical Sophistication Index (Gold-MSI) questionnaire to evaluate their music expertise on a continuous scale. Gold-MSI considers participants' daily-life exposure to music learning experiences (formal and informal), instead of merely classifying people into different groups according to how many years they have been trained in music. Participants were instructed to report, via a 3-alternative forced choice task, "what a person said": /Ba/, /Ga/ or /Da/. The experiment consisted of 96 audiovisual congruent trials and 96 audiovisual incongruent (McGurk) trials. We observed no significant correlations between the susceptibility of the McGurk effect and the different subscales of the Gold-MSI (active engagement, perceptual abilities, music training, singing abilities, emotion) or the general musical sophistication composite score. Together, these findings suggest that music training experience does not modulate audiovisual integration in speech as reflected by the McGurk effect.

Exploring quantitative measures in metacognition of emotion.

Metacognition of emotion (meta-emotion) refers to the ability to evaluate and identify one's emotional feelings. No previous study has defined and measured this construct through objective and quantitative procedures. We established a reliable method to measure meta-emotion. With a two-interval forced-choice procedure, participants selected which of two pictures elicited stronger positive emotion; via the Law of Comparative Judgment, their responses were used to compute individual psychological distances for the emotional responses triggered by the pictures. Then, participants were asked to judge whether a pre-exposed picture induced a stronger positive emotion than the median of that elicited by the whole picture set, followed by a confidence rating. By utilizing each individual's psychological distance, the correctness of a participant's emotional experience was quantified by d', and meta-emotion was quantified using meta-d', M-ratio, and M-diff as indices of metacognitive sensitivity and efficiency based on Signal-Detection Theory. Test-retest reliabilities, validated by Spearman correlation, were observed in meta-d', M-ratio, and marginally with M-diff, suggesting the stability of meta-emotion in the current design. This study unveils a validated procedure to quantify meta-emotion, extendable for assessing metacognition of other subjective feelings. Nevertheless, caution is warranted in interpretation, as the measured processes may be influenced by non-metacognitive factors.

Adaptation and exogenous attention interact in the early visual cortex: A TMS study.

Our capacity to process information is constrained by the limited energy available to the brain and the high energy cost of cortical computation [1]. To help manage limited resources and optimize our sensitivity to visual information, adaptation diminishes sensitivity for repetitive stimuli, whereas attention enhances the representation of relevant information [2]. Transcranial magnetic stimulation (TMS) to early visual cortex (V1/V2) eliminates the response-gain effect of exogenous (involuntary) attention on contrast sensitivity: the benefit at the attended location and the cost at the unattended location [3]. Here we investigate whether adaptation modulates the exogenous attentional effect on perception under TMS to V1/V2. Observers performed an orientation discrimination task while attending to one of two stimuli, with or without adaptation. Following a valid, neutral or invalid attentional cue, two cortically-magnified Gabor patches were presented in the stimulated region (matching each observer's phosphene location) and its contralateral symmetric region. A response cue indicated the patch whose orientation observers had to discriminate. The response cue either matched-target stimulated-or did not match- distractor stimulated-the stimulated side. Without adaptation, the exogenous attention response-gain effect emerged in the distractor-stimulated condition-increased contrast sensitivity at the attended location and decreased at the unattended location-but these effects were eliminated in the target-stimulated condition, consistent with our previous findings. Critically, after adaptation, response gain of exogenous attention was observed in both distractor-stimulated and target-stimulated conditions. These results reveal that (1) adaptation and attention interact in the early visual cortex, (2) adaptation shields exogenous attention from TMS effects.

An Effective Entropy-Assisted Mind-Wandering Detection System Using EEG Signals of MM-SART Database.

Mind-wandering (MW), which is usually defined as a lapse of attention has negative effects on our daily life. Therefore, detecting when MW occurs can prevent us from those negative outcomes resulting from MW. In this work, we first collected a multi-modal Sustained Attention to Response Task (MM-SART) database for MW detection. Eighty-two participants' data were collected in our dataset. For each participant, we collected measures of 32-channels electroencephalogram (EEG) signals, photoplethysmography (PPG) signals, galvanic skin response (GSR) signals, eye tracker signals, and several questionnaires for detailed analyses. Then, we propose an effective MW detection system based on the collected EEG signals. To explore the non-linear characteristics of the EEG signals, we utilize entropy-based features. The experimental results show that we can reach 0.712 AUC score by using the random forest (RF) classifier with the leave-one-subject-out cross-validation. Moreover, to lower the overall computational complexity of the MW detection system, we propose correlation importance feature elimination (CIFE) along with AUC-based channel selection. By using two most significant EEG channels, we can reduce the training time of the classifier by 44.16%. By applying CIFE on the feature set, we can further improve the AUC score to 0.725 but with only 14.6% of the selection time compared with the recursive feature elimination (RFE). Finally, we can apply the current work to educational scenarios nowadays, especially in remote learning systems.

Seeing food fast and slow: Arousing pictures and words have reverse priorities in accessing awareness.

Previous studies have shown that stimuli triggering higher arousal (e.g., attractiveness) can access awareness faster than those triggering lower arousal, yet no studies have examined the effect of food calories. Since food brings us energy, satiety, and positive emotions, food stimuli bringing higher arousal would likely have higher priority in accessing awareness over those with lower arousal. We used high-calorie and low-calorie food stimuli as representatives for high and low arousal stimuli, respectively, based on the tight relationship between calorie and arousal. By adopting the breaking continuous flash suppression (b-CFS) paradigm, we had high-calorie and low-calorie food pictures or words presented dichoptically with dynamic Mondrian masks and measured the time for food stimuli to be released from suppression. Our results showed that high-calorie food pictures could access visual awareness faster than low-calorie food pictures (Experiment 1), and the reverse pattern was observed for food words (Experiment 2). We ruled out the possibility of the difference in low-level features (Experiment 3) and post-perceptual response bias (Experiment 4) as the causes for the observed b-CFS time differences. This study revealed the dissociation of the unconscious processing of pictures and words, which may rely on mechanisms related to attentional capture. High-arousing stimuli do not always enjoy priority in accessing visual awareness.

When Eyes Wander Around: Mind-Wandering as Revealed by Eye Movement Analysis with Hidden Markov Models.

Mind-wandering has been shown to largely influence our learning efficiency, especially in the digital and distracting era nowadays. Detecting mind-wandering thus becomes imperative in educational scenarios. Here, we used a wearable eye-tracker to record eye movements during the sustained attention to response task. Eye movement analysis with hidden Markov models (EMHMM), which takes both spatial and temporal eye-movement information into account, was used to examine if participants' eye movement patterns can differentiate between the states of focused attention and mind-wandering. Two representative eye movement patterns were discovered through clustering using EMHMM: centralized and distributed patterns. Results showed that participants with the centralized pattern had better performance on detecting targets and rated themselves as more focused than those with the distributed pattern. This study indicates that distinct eye movement patterns are associated with different attentional states (focused attention vs. mind-wandering) and demonstrates a novel approach in using EMHMM to study attention. Moreover, this study provides a potential approach to capture the mind-wandering state in the classroom without interrupting the ongoing learning behavior.

In search of blue-light effects on cognitive control.

People are constantly exposed to blue light while engaging in work. It is thus crucial to understand if vast exposure to blue light influences cognitive control, which is essential for working efficiently. Previous studies proposed that the stimulation of intrinsically photosensitive retinal ganglion cells (ipRGCs), a newly discovered photoreceptor that is highly sensitive to blue light, could modulate non-image forming functions. Despite studies that showed blue light (or ipRGCs) enhances brain activations in regions related to cognitive control, how exposure to blue light changes our cognitive control behaviorally remains elusive. We examined whether blue light influences cognitive control through three behavioral tasks in three studies: the sustained attention to response task (SART), the task-switching paradigm, and the Stroop task. Classic effects of the SART, switch cost, and the Stroop effect were found, but no differences were observed in results of different background lights across the six experiments. Together, we conclude that these domains of cognitive control are not influenced by blue light and ipRGCs, and whether the enhancement of blue light on brain activities extends to the behavioral level should be carefully re-examined.

Blue-light effects on saccadic eye movements and attentional disengagement.

People are constantly exposed to high-energy blue light as they spend considerable amounts of time reading and browsing materials on electronic products like computers and cellphones. Recent studies suggest that the stimulation of intrinsically photosensitive retinal ganglion cells (ipRGCs)-a newly discovered type of photoreceptor shown to be particularly sensitive to blue light-activates brain regions related to eye movements and attentional orienting (e.g., frontal eye fields). It remains unclear, however, whether and how blue light affects eye movements and attention behaviorally. We examined this by adopting the gap paradigm in which participants made saccades to a peripheral target as quickly and accurately as possible while the fixation sign vanished (i.e., the gap condition) or remained visible. Participants were exposed to blue and orange light on two separate days. Faster saccade latency under blue light was found across two experiments, and the results indicate that blue light shortened saccade latency when attention and eye movements operate simultaneously. Our findings provide evidence for the blue-light facilitatory effect on eye movements and attentional disengagement, and suggest that blue light can enhance the speed of saccadic eye movements.

Resting-State fMRI Associated with Stop-Signal Task Performance in Healthy Middle-Aged and Elderly People.

Several brain regions and connectivity networks may be altered as aging occurs. We are interested in investigating if resting-state functional magnetic resonance imaging (RS-fMRI) can also be valid as an indicator of individual differences in association with inhibition performance among aged (including middle-aged) people. Seventy-two healthy adults (40-77 years of age) were recruited. Their RS-fMRI images were acquired and analyzed via two cluster-analysis methods: local synchronization of spontaneous brain activity measured by regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuations (fALFF) of blood oxygenation level-dependent signals. After the RS-fMRI acquisition, participants were instructed to perform a stop-signal task, in which the stop signal reaction time (SSRT) was calculated based on the horse-race model. Among participants, the ReHo/fALFF and SSRT were correlated with and without partialling-out the effect of age. The results of this study showed that, although aging may alter brain networks, the spontaneous activity of the age-related brain networks can still serve as an effective indicator of individual differences in association with inhibitory performance in healthy middle-aged and elderly people. This is the first study to use both ReHo and fALFF on the same dataset for conjunction analyses showing the relationship between stopping performance and RS-fMRI in the elderly population. The relationship may have practical clinical applications. Based on the overall results, the current study demonstrated that the bilateral inferior frontal gyrus and parts of the default mode network activation were negatively correlated with SSRT, suggesting that they have crucial roles in inhibitory function. However, the pre-supplementary motor area (pre-SMA) and SMA played only a small role during the resting state in association with stopping performance.

Glucose tolerance and insulin sensitivity following an one-week volleyball competition.

The purpose of the study was to compare glucose tolerance and insulin sensitivity between trained (TR) and competition (CP) states, in relation to cortisol and testosterone levels. Sixteen highly trained volleyball players voluntarily participated in this study. The first testing session (TR state) occurred 1 week before the start of national level volleyball CP, and the second testing session (CP state) occurred next morning after the 1-week CP. Fasted serum sample was used for measuring cortisol and testosterone. Subjects were then orally challenged with 75 g of glucose solution for determinations of oral glucose tolerance test (OGTT) and insulin response. Under both fasted and glucose challenged conditions, glucose levels of CP were not different from TR state, whereas insulin levels of CP were significantly elevated above TR (50 min: from 78.8 +/- 8.7 to 96.6 +/- 8.1 microU/ml, P < 0.05; 80 min: from 62.8 +/- 7.0 to 82.0 +/- 7.3; P < 0.05). Muscle creatine kinase (CK) level in blood was significantly increased above TR, suggesting greater muscle damage by CP. Serum leptin level, percent fat mass, and body weight were not different between two states. CP significantly increased serum cortisol level without significantly change in testosterone level. The new finding of the study was that volleyball CP reduced the whole-body insulin sensitivity significantly compared to TR state. The greater level of insulin concentration under CP state appears to be associated with elevated serum cortisol level. Despites the benefit of increased physical activity on metabolic function is widely recognized, physiological stress associated with CP can result in attenuation of systemic insulin sensitivity compared TR state.

Effect of a two-month detraining on glucose tolerance and insulin sensitivity in athletes--link to adrenal steroid hormones.

Reduction in physical activity has been demonstrated to associate with the increased risk in insulin resistance and type 2 diabetes. To determine whether alteration in insulinemia, due to abstention from regular exercise training, is associated with changes in serum dehydroepiandrosterone sulfate (DHEA-S) and cortisol, 18 highly trained badminton players (21.2 +/- 0.3 years) were enrolled into a 2-month detraining study. Fasting serum insulin, glucose, DHEA-S, and cortisol were determined at trained state and at day 60 of detraining. Glucose tolerance and insulin sensitivity were assessed by an oral glucose tolerance test (OGTT). The 2-month detraining increased fasting glucose and insulin concentrations and body weight slightly, but did not significantly affect glucose tolerance and insulin response curve, in which 10 subjects had increased and 8 subjects had slightly decreased in the area under curve for insulin (IAUC). In the subjects with increased IAUC, serum cortisol was also elevated (from 0.44 +/- 0.07 to 0.83 +/- 0.26 U/l, P < 0.05) in parallel, and serum creatine kinase (CK) was unaltered during detraining. Whereas in the subjects with decreased IAUC, serum cortisol (from 0.51 +/- 0.19 to 0.54 +/- 0.14 U/l, no significance) was not changed and serum creatine kinase (from 461 +/- 179 to 151 +/- 21 U/l) was decreased during detraining. Two groups of detrained subjects exhibited a similar reduction in serum DHEA-S levels and slight elevation in body weight. The novel finding of the study is that the changes in serum cortisol, but not DHEA-S, were associated with the change in insulin sensitivity during early phase of lifestyle change from physically active to sedentary, and this response appears to be varied individually among athletes.

Glycogen overload by postexercise insulin administration abolished the exercise-induced increase in GLUT4 protein.

To elucidate the role of muscle glycogen storage on regulation of GLUT4 protein expression and whole-body glucose tolerance, muscle glycogen level was manipulated by exercise and insulin administration. Sixty Sprague-Dawley rats were evenly separated into three groups: control (CON), immediately after exercise (EX0), and 16 h after exercise (EX16). Rats from each group were further divided into two groups: saline- and insulin-injected. The 2-day exercise protocol consisted of 2 bouts of 3-h swimming with 45-min rest for each day, which effectively depleted glycogen in both red gastrocnemius (RG) and plantaris muscles. EX0 rats were sacrificed immediately after the last bout of exercise on second day. CON and EX16 rats were intubated with 1 g/kg glucose solution following exercise and recovery for 16 h before muscle tissue collection. Insulin (0.5 microU/kg) or saline was injected daily at the time when glucose was intubated. Insulin injection elevated muscle glycogen levels substantially in both muscles above saline-injected group at CON and EX16. With previous day insulin injection, EX0 preserved greater amount of postexercise glycogen above their saline-injected control. In the saline-injected rats, EX16 significantly increased GLUT4 protein level above CON, concurrent with muscle glycogen supercompensation. Insulin injection for EX16 rats significantly enhanced muscle glycogen level above their saline-injected control, but the increases in muscle GLUT4 protein and whole-body glucose tolerance were attenuated. In conclusion, the new finding of the study was that glycogen overload by postexercise insulin administration significantly abolished the exercise-induced increases in GLUT4 protein and glucose tolerance.