The Important Role of the Right Dorsolateral Prefrontal Cortex in Conflict Adaptation: A Combined Voxel-Based Morphometry and Continuous Theta Burst Stimulation Study.

Humans can flexibly adjust their executive control to resolve conflicts. Conflict adaptation and conflict resolution are crucial aspects of conflict processing. Functional neuroimaging studies have associated the dorsolateral prefrontal cortex (DLPFC) with conflict processing, but its causal role remains somewhat controversial. Moreover, the neuroanatomical basis of conflict processing has not been thoroughly examined. In this study, the Stroop task, a well-established measure of conflict, was employed to investigate (1) the neuroanatomical basis of conflict resolution and conflict adaptation with the voxel-based morphometry analysis, (2) the causal role of DLPFC in conflict processing with the application of the continuous theta burst stimulation to DLPFC. The results revealed that the Stroop effect was correlated to the gray matter volume of the precuneus, postcentral gyrus, and cerebellum, and the congruency sequence effect was correlated to the gray matter volume of superior frontal gyrus, postcentral gyrus, and lobule paracentral gyrus. These findings indicate the neuroanatomical basis of conflict resolution and adaptation. In addition, the continuous theta burst stimulation over the right DLPFC resulted in a significant reduction in the Stroop effect of RT after congruent trials compared with vertex stimulation and a significant increase in the Stroop effect of accuracy rate after incongruent trials than congruent trials, demonstrating the causal role of right DLPFC in conflict adaptation. Moreover, the DLPFC stimulation did not affect the Stroop effect of RT and accuracy rate. Overall, our study offers further insights into the neural mechanisms underlying conflict resolution and adaptation.

Identifying individual's distractor suppression using functional connectivity between anatomical large-scale brain regions.

Distractor suppression (DS) is crucial in goal-oriented behaviors, referring to the ability to suppress irrelevant information. Current evidence points to the prefrontal cortex as an origin region of DS, while subcortical, occipital, and temporal regions are also implicated. The present study aimed to examine the contribution of communications between these brain regions to visual DS. To do it, we recruited two independent cohorts of participants for the study. One cohort participated in a visual search experiment where a salient distractor triggering distractor suppression to measure their DS and the other cohort filled out a Cognitive Failure Questionnaire to assess distractibility in daily life. Both cohorts collected resting-state functional magnetic resonance imaging (rs-fMRI) data to investigate function connectivity (FC) underlying DS. First, we generated predictive models of the DS measured in visual search task using resting-state functional connectivity between large anatomical regions. It turned out that the models could successfully predict individual's DS, indicated by a significant correlation between the actual and predicted DS (r = 0.32, p < 0.01). Importantly, Prefrontal-Temporal, Insula-Limbic and Parietal-Occipital connections contributed to the prediction model. Furthermore, the model could also predict individual's daily distractibility in the other independent cohort (r = -0.34, p < 0.05). Our findings showed the efficiency of the predictive models of distractor suppression encompassing connections between large anatomical regions and highlighted the importance of the communications between attention-related and visual information processing regions in distractor suppression. Current findings may potentially provide neurobiological markers of visual distractor suppression.

Task functional networks predict individual differences in the speed of emotional facial discrimination.

Every individual experiences negative emotions, such as fear and anger, significantly influencing how external information is perceived and processed. With the gradual rise in brain-behavior relationship studies, analyses investigating individual differences in negative emotion processing and a more objective measure such as the response time (RT) remain unexplored. This study aims to address this gap by establishing that the individual differences in the speed of negative facial emotion discrimination can be predicted from whole-brain functional connectivity when participants were performing a face discrimination task. Employing the connectome predictive modeling (CPM) framework, we demonstrated this in the young healthy adult group from the Human Connectome Project-Young Adults (HCP-YA) dataset and the healthy group of the Boston Adolescent Neuroimaging of Depression and Anxiety (BANDA) dataset. We identified distinct network contributions in the adult and adolescent predictive models. The highest represented brain networks involved in the adult model predictions included representations from the motor, visual association, salience, and medial frontal networks. Conversely, the adolescent predictive models showed substantial contributions from the cerebellum-frontoparietal network interactions. Finally, we observed that despite the successful within-dataset prediction in healthy adults and adolescents, the predictive models failed in the cross-dataset generalization. In conclusion, our study shows that individual differences in the speed of emotional facial discrimination can be predicted in healthy adults and adolescent samples using their functional connectivity during negative facial emotion processing. Future research is needed in the derivation of more generalizable models.

cTBS to Right DLPFC Modulates Physiological Correlates of Conflict Processing: Evidence from a Stroop task.

Conflict typically occurs when goal-directed processing competes with more automatic responses. Though previous studies have highlighted the importance of the right dorsolateral prefrontal cortex (rDLPFC) in conflict processing, its causal role remains unclear. In the current study, the behavioral experiment, the continuous theta burst stimulation (cTBS), and the electroencephalography (EEG) were combined to explore the effects of behavioral performance and physiological correlates during conflict processing, after the cTBS over the rDLPFC and vertex (the control condition). Twenty-six healthy participants performed the Stroop task which included congruent and incongruent trials. Although the cTBS did not induce significant changes in the behavioral performance, the cTBS over the rDLPFC reduced the Stroop effects of conflict monitoring-related frontal-central N2 component and theta oscillation, and conflict resolution-related parieto-occipital alpha oscillation, compared to the vertex stimulation. Moreover, a significant hemispheric difference in alpha oscillation was exploratively observed after the cTBS over the rDLPFC. Interestingly, we found the rDLPFC stimulation resulted in significantly reduced Stroop effects of theta and gamma oscillation after response, which may reflect the adjustment of cognitive control for the next trial. In conclusion, our study not only demonstrated the critical involvement of the rDLPFC in conflict monitoring, conflict resolution processing, and conflict adaptation but also revealed the electrophysiological mechanism of conflict processing mediated by the rDLPFC.

Shared and distinct structure-function substrates of heterogenous distractor suppression ability between high and low working memory capacity individuals.

Salient stimuli can capture attention in a bottom-up manner; however, this attentional capture can be suppressed in a top-down manner. It has been shown that individuals with high working memory capacity (WMC) can suppress salient­but-irrelevant distractors better than those with low WMC; however, neural substrates underlying this difference remain unclear. To examine this, participants with high or low WMC (high-/low-WMC, n = 44/44) performed a visual search task wherein a color singleton item served as a salient distractor, and underwent structural and resting-state functional magnetic resonance imaging scans. Behaviorally, the color singleton distractor generally reduced the reaction time (RT). This RT benefit (ΔRT) was higher in the high-WMC group relative to the low-WMC group, indicating the superior distractor suppression ability of the high-WMC group. Moreover, leveraging voxel-based morphometry analysis, gray matter morphology (volume and deformation) in the ventral attention network (VAN) was found to show the same, positive associations with ΔRT in both WMC groups. However, correlations of the opposite sign were found between ΔRT and gray matter morphology in the frontoparietal (FPN)/default mode network (DMN) in the two WMC groups. Furthermore, resting-state functional connectivity analysis centering on regions with a structural-behavioral relationship found that connections between the left orbital and right superior frontal gyrus (hubs of DMN and VAN, respectively) was correlated with ΔRT in the high-WMC group (but not in the low-WMC group). Collectively, our work present shared and distinct neuroanatomical substrates of distractor suppression in high- and low-WMC individuals. Furthermore, intrinsic connectivity of the brain network hubs in high-WMC individuals may account for their superior ability in suppressing salient distractors.

Visual Selective Attention P300 Source in Frontal-Parietal Lobe: ERP and fMRI Study.

Visual selective attention can be achieved into bottom-up and top-down attention. Different selective attention tasks involve different attention control ways. The pop-out task requires more bottom-up attention, whereas the search task involves more top-down attention. P300, which is the positive potential generated by the brain in the latency of 300 ~ 600 ms after stimulus, reflects the processing of attention. There is no consensus on the P300 source. The aim of present study is to study the source of P300 elicited by different visual selective attention. We collected thirteen participants' P300 elicited by pop-out and search tasks with event-related potentials (ERP). We collected twenty-six participants' activation brain regions in pop-out and search tasks with functional magnetic resonance imaging (fMRI). And we analyzed the sources of P300 using the ERP and fMRI integration with high temporal resolution and high spatial resolution. ERP results indicated that the pop-out task induced larger P300 than the search task. P300 induced by the two tasks distributed at frontal and parietal lobes, with P300 induced by the pop-out task mainly at the parietal lobe and that induced by the search task mainly at the frontal lobe. Further ERP and fMRI integration analysis showed that neural difference sources of P300 were the right precentral gyrus, left superior frontal gyrus (medial orbital), left middle temporal gyrus, left rolandic operculum, right postcentral gyrus, and left angular gyrus. Our study suggests that the frontal and parietal lobes contribute to the P300 component of visual selective attention.

Where there is no object formation, there is no perceptual organization: Evidence from the configural superiority effect.

Object formation is considered the aim of perceptual organization, but such a proposition has been neglected in empirical studies. In the current study, we investigated the role of object formation in configural superiority. Essentially, discrimination on bar orientations was enhanced by adding a right angle to each of the bars. Such facilitation is due to the emergent feature (EF) of closure formed by combining the bars with right angles. To study object formation, visual stimuli were generated by random dot stereograms to form objects or holes in 3D. Behaviorally, we found that the EF of closure facilitated oddball discrimination on objects, as demonstrated by previous studies, but did not facilitate oddball discrimination on holes with the same shape as objects. Multivariate pattern analysis of functional magnetic resonance imaging (fMRI) data showed that the EF of closure increased the object classification accuracy compared to the holes in the lateral occipital cortex (LOC), where object information is encoded, but not in the early visual cortex (EVC). The neural representations of objects and holes with and without EFs were further investigated using representational similarity analysis. The results demonstrate that in the LOC, the neural representations of objects with EFs showed a greater difference than those of the other three, that is, objects without EFs and holes with or without EFs. However, the uniqueness of objects with EFs was not observed in the EVC. Thus, our results suggest that the EF of closure, which leads to the configural superiority effect, only emerges for objects but not for holes, and only in the LOC but not the EVC. Our study provides the first empirical evidence suggesting that object formation plays an indispensable role in perceptual organization.

Transcranial magnetic stimulation over the right dorsolateral prefrontal cortex modulates visuospatial distractor suppression.

Visual selective attention allows us to filter relevant inputs from irrelevant inputs during visual processing. In contrast to rich research exploring how the brain facilitates task-relevant inputs, less is known about how the brain suppresses irrelevant inputs. In this study, we used transcranial magnetic stimulation (TMS) to investigate the causal role of the right dorsolateral prefrontal cortex (DLPFC), a crucial brain area for attentional control, in distractor suppression. Specifically, 10-Hz repetitive TMS (rTMS) was applied to the right DLPFC and Vertex at the stimuli onset (stimuli-onset TMS) or 500 ms prior to the stimuli onset (prestimuli TMS). In a variant of the Posner cueing task, participants were instructed to identify the shape of a white target while ignoring a white or colored distractor whose location was either cued in advance or uncued. As anticipated, either the location cue or the colored distractor led to faster responses. Notably, the location cueing effect was eliminated by stimuli-onset TMS to the right DLPFC, but not by prestimuli TMS. Further analyses showed that stimuli-onset TMS quickened responses to uncued trials, and this TMS effect was derived from the inhibition at the distractor in both visual fields. In addition, TMS over the right DLPFC had no specific effect on the colored distractor compared to the white one. Considered collectively, these findings indicate that the DLPFC plays a crucial role in visuospatial distractor suppression and acts upon stimuli presentation. Besides, it seems the DLPFC contributes more to location-based distractor suppression than to color-based one.

Probing the role of the right inferior frontal gyrus during Pain-Related empathy processing: Evidence from fMRI and TMS.

Recent studies have suggested that the right inferior frontal gyrus (rIFG) may be involved in pain-related empathy. To verify the role of the rIFG, we performed a functional magnetic resonance imaging (fMRI) experiment to replicate previous research and further designed a noninvasive repetitive transcranial magnetic stimulation (rTMS) experiment to probe the causal role of the rIFG in pain-related empathy processing. We assigned 74 volunteers (37 females) to three groups. Group 1 (n = 26) performed a task in which participants were required to perceive pain in others (task of pain: TP) and we used fMRI to observe the activity of the rIFG during pain-related empathy processing. Then, we applied online rTMS to the rIFG and the vertex site (as reference site) to observe the performance of Group 2 (n = 24; performing TP) and Group 3 (n = 24; performing a control task of identifying body parts; task of body: TB). fMRI experiment demonstrated stronger activation in the rIFG than in the vertex during the perception of pain in others (p < .0001, Bonferroni-corrected). rTMS experiment indicated that when the rIFG was temporarily disrupted, participants perceived pain in others significantly more slowly (p < .0001, Bonferroni-corrected) than when the vertex was disrupted. Our results provide evidence that the rIFG is involved in pain-related empathy processing, which yields insights into how the brain perceives pain in others.

The role of frontal pursuit area in interaction between smooth pursuit eye movements and attention: A TMS study.

Close coupling between attention and smooth pursuit eye movements has been widely established and frontal eye field (FEF) is a "hub" region for attention and eye movements. Frontal pursuit area (FPA), a subregion of the FEF, is part of neural circuit for the pursuit, here, we directly checked the role of the FPA in the interaction between the pursuit and attention. To do it, we applied a dual-task paradigm where an attention demanding task was integrated into the pursuit target and interrupted the FPA using transcranial magnetic stimulation (TMS). In the study, participants were required to pursue a moving circle with a letter inside, which changed to another one every 100 ms and report whether "H" (low attentional load) or one of "H," "S," or "L" (high attentional load) appeared during the trial. As expected, increasing the attentional load decreased accuracy of the letter detection. Importantly, the FPA TMS had no effect on both the pursuit and letter detection tasks in the low load condition, whereas it reduced 200 to 320 ms gain, but tended to increase the letter detection accuracy in the high load condition. Moreover, individual's FPA TMS effect on pursuit gain was significantly correlated with that on letter detection accuracy. Presumably, the pursuit gain control by the FPA was compensated by attention in low load condition, and the FPA may flexibly allocate attentional resources between the pursuit and letter detection task in high load condition. Altogether, it seems that the FPA has a control over attentional allocation between tasks.

Distinct neural substrates underlying target facilitation and distractor suppression: A combined voxel-based morphometry and resting-state functional connectivity study.

Selective attention, the ability to filter relevant from a sea of sensory information, relies on the prioritization of goal-relevant information (target facilitation) and the suppression of goal-irrelevant information (distractor suppression). Although several lines of evidence have shown that target facilitation and distractor suppression were mediated by distinct mechanisms, the underlying neural substrates remain unclear. To address this question, we acquired structural and resting-state magnetic resonance imaging scans, as well as behavioral data from a modified Posner cueing task. Specifically, the location of a target (Target Cue, TC) and a distractor (Distractor Cue, DC) was either cued in advance to separately trigger target facilitation and distractor suppression, or no predictive information was provided, serving as a baseline. We combined voxel-based morphometry (VBM) and resting-state functional connectivity (rsFC) analyses to explore the neural correlates of behavioral benefits, yielding the following results. First, behavioral data showed faster responses to TC and DC conditions compared to baseline, the benefits of which were named TC-benefit and DC-benefit. Second, the VBM analysis revealed that the gray matter volume (GMV) in the superior frontal (SFG) and postcentral gyrus inversely correlated with individual TC-benefit, while the GMV in the superior parietal lobe, middle frontal gyrus, and angular gyrus inversely correlated with individual DC-benefit, indicating that target facilitation and distractor suppression was associated with the GMV of distinct and distributed regions in the frontoparietal cortex. Third, the rsFC analysis with the SFG as a seed region further found distinct patterns of rsFC for target facilitation and distractor suppression. Specifically, individual TC-benefit were positively correlated with distributed connections between the SFG and brain regions, mainly within the ventral attention and somato-motor network; but individual DC-benefit were positively correlated with centralized connections between the SFG and brain regions, mainly within the frontoparietal, dorsal attention and ventral attention network. Finally, a multiple linear regression analysis showed that the GMV and rsFC could jointly explain individual differences in TC- and DC-benefit. Taken together, these results provided neural evidence for different structural and functional substrates underlying target facilitation and distractor suppression.

Linking brain structure and activation in anterior insula cortex to explain the trait empathy for pain.

The ability to perceive, understand, and react to the feelings of others' pain is referred to as empathy for pain which is composed of two components, affective-perceptual empathy and cognitive-evaluative empathy. Recent reviews on the neural mechanisms of empathetic pain showed the anterior insula (AI) cortex as a core circuit for empathy. However, little is known about the modulation of brain anatomy and empathic responses by trait measures of empathy (trait empathy). Thus, we investigated whether individual variation in the personality trait of empathy is associated with individual variation in the structure of specific brain regions using voxel-based morphometry (VBM). We further investigated the relationship between the trait empathy and the activity of the same regions using state measures of empathy for pain in a trial-by-trial fashion in the given situation. VBM analysis indicated a small but significant negative relationship between trait empathy and gray matter volume in the bilateral AI. Functional MRI study further demonstrated that experimentally induced activity of the bilateral AI during state empathy for pain was also correlated with trait empathy. An asymmetry exists between the right and left AI between the affective and cognitive empathy. The right AI was found to be involved in the affective-perceptual form of empathy and the left AI was active in cognitive-evaluative forms of empathy. The interindividual differences in trait empathy may be reflected both in the state empathy and more stable brain structure difference.

The neural basis of semantic cognition in Mandarin Chinese: A combined fMRI and TMS study.

While converging sources of evidence point to the possibility of a large-scale distributed network for semantic cognition, a consensus regarding the underlying subregions and their specific function in this network has not been reached. In the current study, we combined functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) methodology to investigate the neural basis of semantic cognition in Mandarin Chinese. In the fMRI experiment, strong activations were observed in left inferior frontal gyrus (IFG) and left middle temporal gyrus (MTG) for semantic judgment task. Moreover, functional connectivity was found from seed region left IFG to left MTG. Meanwhile, negative correlation between performance and extracted parameter estimates from left IFG to left MTG was detected in semantic task. Subsequent TMS stimulation over left IFG resulted in performance deficits in semantic judgment task, in contrast to other three sites: left MTG, right intraparietal sulcus (IPS) and a control site. We concluded that the neural basis of semantic processing for Mandarin Chinese closely resembled that for alphabetic languages such as English, supporting a language-universal view on semantic cognition.

The success of the representation maintenance affects the memory-guided search processing: an ERP study.

Previous evidence showed that working memory (WM) contents can bias visual selection. However, less is known about how the WM effects change when the WM representation is not held successfully. Here, we investigated this problem using event-related potentials. Subjects maintained a color in WM while performing a search task. The color cue contained the target (valid) or the distractor (invalid). Subjects could either remember the color accurately (correct WM) or not (incorrect WM). An N2-posterior contralateral component and a sustained posterior contralateral negativity (SPCN) were recorded in the valid and incorrect WM condition, while only an attenuated SPCN was elicited in the valid and correct WM condition. No reliable lateralized components were found for the invalid trials. These findings suggest that the WM effects on visual search are affected by the resource interchange between WM and search processes.

A coordinate-based meta-analysis of the n-back working memory paradigm using activation likelihood estimation.

The n-back task is a classical paradigm for functional neuroimaging studies of working memory (WM). The frontal and parietal cortical regions are known to be activated during the task. We used activation likelihood estimation (ALE) to conduct a quantitative meta-analysis of 96 primary studies of n-back task variants based on four conditions: memory loads (1-back, 2-back), object (identity, location), age (younger, older) and gender (male, female). Six cortical regions were consistently activated across all the studies: bilateral middle frontal gyrus (BA 10); bilateral inferior parietal lobule (BA 40); bilateral precuneus (BA 7); left superior frontal gyrus (BA 6); left anterior insula (aI) (BA 13); bilateral thalamus. Further meta-analyses revealed that different regions were sensitive to different conditions: compared with 1-back, 2-back increased activation in left middle frontal gyrus, left inferior frontal gyrus and left aI; compared with object location, object identity increased activation in right aI; young, compared with older subjects showed increased activation in frontal, parietal lobule, and right aI; the comparison between male and female showed no differences. Thus, our findings, showed consistent activation of frontal and parietal cortical regions, while other regions such as the aI, showed different activation patterns depending on varying experimental classification conditions.

Hole superiority effect with 3D figures formed by binocular disparity.

The global-first theory of topological perception claims that topological perception is prior to the perception of local features (e.g., Chen, 1982, 2005). Our previous studies demonstrated a hole superiority effect (HSE): Figures with holes are more detectable than figures without holes. Such an HSE was shown with figures formed by either orientation-defined texture (Zhang, 2009) or a black-and-white contrast (Meng, Cui, Zhou, Chen, & Ma, 2012). The present study used binocular disparity as one more organizing factor for testing the abstract nature of the HSE, indicating holes, as a typical kind of topological invariance, are represented in vision independent of the features that were forming the holes. The disparity-forming figures were well controlled for luminance, spatial frequency, subjective contours, and other nontopological factors, which are commonly considered as counter explanations against the topological theory.

Task-irrelevant emotional faces impair response adjustments in a double-step saccade task.

Cognitive control enables us to adjust behaviours according to task demands, and emotion influences the cognitive control. We examined how task-irrelevant emotional stimuli impact the ability to inhibit a prepared response and then programme another appropriate response. In the study, either a single target or two sequential targets appeared after emotional face images (positive, neutral, and negative). Subjects were required to freely viewed the emotional faces and make a saccade quickly upon target onset, but inhibit their initial saccades and redirect gaze to the second target if it appeared. We found that subjects were less successful at inhibiting their initial saccades as the inter-target delay increased. Emotional faces further reduced their inhibition ability with a longer delay, but not with a shorter delay. When subjects failed to inhibit the initial saccade, the longer delay produced longer intersaccadic interval. Especially, positive faces lengthened the intersaccadic interval with a longer delay. These results showed mere presence of emotional stimuli influences gaze redirection by impairing the ability to cancel a prepared saccade and delaying the programming of a corrective saccade. Therefore, we propose that the modulation of response adjustment exerted by emotional faces is related to the stage of initial response programming.

Motion integration for ocular pursuit does not hinder perceptual segregation of moving objects.

When confronted with a complex moving stimulus, the brain can integrate local element velocities to obtain a single motion signal, or segregate the elements to maintain awareness of their identities. The integrated motion signal can drive smooth-pursuit eye movements (Heinen and Watamaniuk, 1998), whereas the segregated signal guides attentive tracking of individual elements in multiple-object tracking tasks (MOT; Pylyshyn and Storm, 1988). It is evident that these processes can occur simultaneously, because we can effortlessly pursue ambulating creatures while inspecting disjoint moving features, such as arms and legs, but the underlying mechanism is unknown. Here, we provide evidence that separate neural circuits perform the mathematically opposed operations of integration and segregation, by demonstrating with a dual-task paradigm that the two processes do not share attentional resources. Human observers attentively tracked a subset of target elements composing a small MOT stimulus, while pursuing it ocularly as it translated across a computer display. Integration of the multidot stimulus yielded optimal pursuit. Importantly, performing MOT while pursuing the stimulus did not degrade performance on either task compared with when each was performed alone, indicating that they did not share attention. A control experiment showed that pursuit was not driven by integration of only the nontargets, leaving the MOT targets free for segregation. Nor was a predictive strategy used to pursue the stimulus, because sudden changes in its global velocity were accurately followed. The results suggest that separate neural mechanisms can simultaneously segregate and integrate the same motion signals.

Meta-analysis of experimental factors influencing single-pulse TMS effects on the early visual cortex.

Background: Single-pulse transcranial magnetic stimulation (spTMS) applied to the Early Visual Cortex (EVC) has demonstrated the ability to suppress the perception on visual targets, akin to the effect of visual masking. However, the reported spTMS suppression effects across various studies have displayed inconsistency. Objective: We aim to test if the heterogeneity of the spTMS effects can be attributable to variations in experimental factors. Methods: We conducted a meta-analysis using data collected from the PubMed and Web of Science databases spanning from 1995 to March 2024. The meta-analysis encompassed a total of 40 independent experiments drawn from 33 original articles. Results: The findings unveiled an overall significant spTMS suppression effect on visual perception. Nevertheless, there existed substantial heterogeneity among the experiments. Univariate analysis elucidated that the spTMS effects could be significantly influenced by TMS intensity, visual angle of the stimulus, coil type, and TMS stimulators from different manufacturers. Reliable spTMS suppression effects were observed within the time windows of -80 to 0 ms and 50 to 150 ms. Multivariate linear regression analyses, which included SOA, TMS intensity, visual angle of the stimulus, and coil type, identified SOA as the key factor influencing the spTMS effects. Within the 50 to 150 ms time window, optimal SOAs were identified as 112 ms and 98 ms for objective and subjective performance, respectively. Collectively, multiple experimental factors accounted for 22.9% (r = 0.3353) and 39.9% (r = 0.3724) of the variance in objective and subjective performance, respectively. Comparing univariate and multivariate analyses, it was evident that experimental factors had different impacts on objective performance and subjective performance. Conclusion: The present study provided quantitative recommendations for future experiments involving the spTMS effects on visual targets, offering guidance on how to configure experimental factors to achieve the optimal masking effect.

Orientation-dependent local structural properties of Zn(1-x)Mg(x)O nanorods studied by extended X-ray absorption fine structure.

The orientation-dependent structural properties of Zn(1-x)Mg(x)O nanorods with different Mg concentrations were investigated quantitatively using polarization-dependent extended X-ray absorption fine structure (EXAFS) measurements at the Zn K edge. Vertically-aligned Zn(1-x)Mg(x)O nanorods were synthesized on Si substrates using catalyst free metal organic chemical vapor deposition. Polarization-dependent EXAFS measurements showed that Mg ions mainly occupied the Zn sites of the nanorods. EXAFS revealed that the distance between Zn-Mg pairs in all directions is - 0.2 angstroms shorter than that of Zn-Zn pairs and that there is a substantial amount of disorder in the Mg sites of the nanorods, independent of Mg concentrations.