Color-word Matching Stroop Task Research Articles

The joint effect and hemodynamic mechanism of PA and PM2.5 exposure on cognitive function: A randomized controlled trial study

BackgroundWhile PM2.5 has been shown to impair cognitive function, physical activity (PA) is known to enhance it. Nonetheless, considering the increased inhalation of PM2.5 during exercise, the potential of PA to counteract the detrimental effects of PM2.5, along with the underlying hemodynamic mechanisms, remains uncertain. MethodsWe conducted a double-blinded, randomized controlled trial among healthy young adults in Beijing, China. Ninety-three participants were randomly allocated to groups experiencing different intensities of PA interventions, and either subjected to purified or unpurified air conditions. Cognitive function was measured by the Color-Word Matching Stroop task, and the hemodynamic response was measured using functional near-infrared spectroscopy during participants performed the Stroop task both before and after the intervention. Linear mixed-effect models were used to estimate the impact of PA and PM2.5 on cognitive function and hemodynamic response. ResultsThe reaction time for congruent and incongruent Stroop tasks improved by − 80.714 (95% CI: −136.733, −24.695) and − 105.843 (95% CI: −188.6, −23.085) milliseconds after high-intensity interval training (HIIT) intervention. PM2.5 and HIIT had interaction effects on cognition, such that every 1 μg/m3 increase in PM2.5 attenuated the benefits of HIIT on reaction time by 2.231 (95% CI: 0.523, 3.938) and 3.305 (95% CI: 0.791, 5.819) milliseconds for congruent and incongruent Stroop tasks. Moreover, we divided participants into high and low PM2.5 exposure groups based on average PM2.5 concentration (32.980 μg/m3), and found that HIIT intervention in high PM2.5 concentration led to 69.897 (95% CI: 9.317, 130.476) and 99.269 (95% CI: 10.054, 188.485) milliseconds increased in the reaction time of congruent and incongruent Stroop, compared with the control group among low PM2.5. Furthermore, we found a significant interaction effects of PM2.5 and moderate-intensity continuous training (MICT) on the middle frontal gyrus (MFG) and dorsolateral superior frontal gyrus (DLPFC). PM2.5 and HIIT had a significant interaction effect on the DLPFC. ConclusionsHIIT improved cognitive function, but the cognitive benefits of HIIT were attenuated or even reversed under high PM2.5 exposure. The activation of the DLPFC and MFG could serve as hemodynamic mechanisms to explain the joint effect of PA and PM2.5.

Reduced left dorsolateral prefrontal activation in problematic smartphone users during the Stroop task: An fNIRS study.

The widespread use of smartphones has triggered concern over problematic smartphone use (PSPU), as well as the need to elucidate its underlying mechanisms. However, the correlation between cortical activation and deficient inhibitory control in PSPU remains unclear. This study examined inhibitory control using the color-word matching Stroop task and its cortical-activation responses using functional near-infrared spectroscopy (fNIRS) in college students with PSPU (n = 56) compared with a control group (n = 54). At the behavioral level, Stroop interference, coupled with reaction time, was significantly greater in the PSPU group than in the control group. Changes in oxygenated hemoglobin (Oxy-Hb) signals associated with Stroop interference were significantly increased in the left ventrolateral prefrontal cortex, left frontopolar area, and bilateral dorsolateral prefrontal cortex (DLPFC). Moreover, the PSPU group had lower Oxy-Hb signal changes associated with Stroop interference in the left-DLPFC, relative to controls. These results provide first behavioral and neuroscientific evidence using event-related fNIRS method, to our knowledge, that college students with PSPU may have a deficit in inhibitory control associated with lower cortical activation in the left-DLPFC.

Benefit of human moderate running boosting mood and executive function coinciding with bilateral prefrontal activation

Running, compared to pedaling is a whole-body locomotive movement that may confer more mental health via strongly stimulating brains, although running impacts on mental health but their underlying brain mechanisms have yet to be determined; since almost the mechanistic studies have been done with pedaling. We thus aimed at determining the acute effect of a single bout of running at moderate-intensity, the most popular condition, on mood and executive function as well as their neural substrates in the prefrontal cortex (PFC). Twenty-six healthy participants completed both a 10-min running session on a treadmill at 50%{dot{text{V}}text{O}}_{{{text{2peak}}}} and a resting control session in randomized order. Executive function was assessed using the Stroop interference time from the color-word matching Stroop task (CWST) and mood was assessed using the Two-Dimensional Mood Scale, before and after both sessions. Prefrontal hemodynamic changes while performing the CWST were investigated using functional near-infrared spectroscopy. Running resulted in significant enhanced arousal and pleasure level compared to control. Running also caused significant greater reduction of Stroop interference time and increase in Oxy-Hb signals in bilateral PFCs. Besides, we found a significant association among pleasure level, Stroop interference reaction time, and the left dorsolateral PFCs: important brain loci for inhibitory control and mood regulation. To our knowledge, an acute moderate-intensity running has the beneficial of inducing a positive mood and enhancing executive function coinciding with cortical activation in the prefrontal subregions involved in inhibitory control and mood regulation. These results together with previous findings with pedaling imply the specificity of moderate running benefits promoting both cognition and pleasant mood.

Virtual training leads to real acute physical, cognitive, and neural benefits on healthy adults: study protocol for a randomized controlled trial

BackgroundKeeping a certain level of physical activity has beneficial effects on the body itself but also, surprisingly, on cognition: specifically, physical high-intensity intermittent aerobic exercise (HIE) can show improvement on cognitive executive functions. Although, in some cases performing strength or aerobic training is problematic or not feasible. Immersive virtual reality (IVR) can induce the illusory feeling of ownership and agency over a moving virtual body, therefore showing comparable physiological reactions: for example, if an individual is sitting on a chair but his virtual body climbs a hill, the individual’s heart rate increases coherently, as if he is actually walking.In this study, we investigate whether this same illusion can show beneficial consequences on the body as well as on executive functions (using the color-word matching Stroop task) and on its neural substrates (using functional near-infrared spectroscopy [fNIRS]).MethodsIn a cross-over randomized controlled trial, 30 healthy young adults will experience HIE training in IVR (i.e. the virtual body will perform eight sets of 30 s of running followed by 30 s of slow walking, while the participant is completely still) according to two random-ordered conditions: during the experimental condition, the virtual body is displayed in first-person perspective (1PP), while in the control condition, the virtual body is displayed in third-person perspective (3PP). To confirm that individuals have the illusion of ownership and agency over the virtual body in 1PP (and not in 3PP), we will record the heart rate, in addition to subjective questionnaires. Before and after every IVR sessions (one week apart), we will measure cortical hemodynamic changes in the participants’ prefrontal cortex using the fNIRS device during the Stroop task’s execution.DiscussionFrom a theoretical perspective, we could prove that the sense of body ownership and agency can modulate physical and cognitive parameters, even in the absence of actual movements; from a clinical perspective, these results could be useful to train cognition and body simultaneously, in a completely safe environment.Trial registrationUniversity Hospital Medical Information Network Clinical Trial Registry, UMIN000034255. Registered on 1 October 2018.

Effects of acute exercise in the sitting position on executive function evaluated by the Stroop task in healthy older adults.

[Purpose] Exercise effects on executive functioning depend on exercise mode. We tested the effects of three acute exercises in the sitting position—stepping, stretching, and finger movement—on older adults’ executive functioning in comparison to a resting state (i.e., control condition). [Subjects and Methods] Participants were 26 healthy older adults (mean age, 71.8 ± 4.7 years). All participants performed the three sitting exercises for 10 minutes; resting for an equal amount of time was used as a control condition. These four conditions were presented in random order. The color-word matching Stroop task was used to evaluate executive function before and after the sitting exercises and control condition. [Results] All three sitting exercises significantly reduced Stroop interference scores, while the control condition did not. There was a significant difference between the finger movement exercise and the control condition in pre-to-post-intervention changes in Stroop interference scores. [Conclusion] The acute finger movement exercise was especially beneficial for executive function as evaluated by the color-word matching Stroop task.

A transferable high-intensity intermittent exercise improves executive performance in association with dorsolateral prefrontal activation in young adults

Although growing attention has been drawn to attainable, high-intensity intermittent exercise (HIE)-based intervention, which can improve cardiovascular and metabolic health, for sedentary individuals, there is limited information on the impact and potential benefit of an easily attainable HIE intervention for cognitive health. We aimed to reveal how acute HIE affects executive function focusing on underlying neural substrates. To address this issue, we examined the effects of acute HIE on executive function using the color-word matching Stroop task (CWST), which produces a cognitive conflict in the decision-making process, and its neural substrate using functional near infrared spectroscopy (fNIRS). Twenty-five sedentary young adults (mean age: 21.0 ± 1.6 years; 9 females) participated in two counter-balanced sessions: HIE and resting control. The HIE session consisted of two minutes of warm-up exercise (50 W load at 60 rpm) and eight sets of 30 s of cycling exercise at 60% of maximal aerobic power (mean: 127 W ± 29.5 load at 100 rpm) followed by 30 s of rest on a recumbent-ergometer. Participants performed a CWST before and after the 10-minute exercise session, during both of which cortical hemodynamic changes in the prefrontal cortex were monitored using fNIRS. Acute HIE led to improved Stroop performance reflected by a shortening of the response time related to Stroop interference. It also evoked cortical activation related to Stroop interference on the left-dorsal-lateral prefrontal cortex (DLPFC), which corresponded significantly with improved executive performance. These results provide the first empirical evidence using a neuroimaging method, to our knowledge, that acute HIE improves executive function, probably mediated by increased activation of the task-related area of the prefrontal cortex including the left-DLPFC.

Graph theoretical approach to functional connectivity in prefrontal cortex via fNIRS.

Functional near-infrared spectroscopy (fNIRS) has been proposed as an affordable, fast, and robust alternative to many neuroimaging modalities yet it still has long way to go to be adapted in the clinic. One request from the clinicians has been the delivery of a simple and straightforward metric (a so-called biomarker) from the vast amount of data a multichannel fNIRS system provides. We propose a simple-straightforward signal processing algorithm derived from [Formula: see text] data collected during a modified version of the color-word matching Stroop task that consists of three different conditions. The algorithm starts with a wavelet-transform-based preprocessing, then uses partial correlation analysis to compute the functional connectivity matrices at each condition and then computes the global efficiency values. To this end, a continuous wave 16 channels fNIRS device (ARGES Cerebro, Hemosoft Inc., Turkey) was used to measure the changes in [Formula: see text] concentrations from 12 healthy volunteers. We have considered 10% of strongest connections in each network. A strong Stroop interference effect was found between the incongruent against neutral condition ([Formula: see text]) while a similar significance was observed for the global efficiency values decreased from neutral to congruent to incongruent conditions [[Formula: see text], [Formula: see text]]. The findings bring us closer to delivering a biomarker derived from fNIRS data that can be reliably and easily adopted by the clinicians.

Functional connectivity of the PFC via partial correlation

Functional near-infrared spectroscopy (fNIRS) has been applied to study of brain oxygenation and metabolism. In this study, we aimed to investigate the partial correlation (PC) in fNIRS signals on functional connectivity in the prefrontal cortex (PFC) during a modified version of the color-word matching Stroop task. A continuous wave 16 channels near-infrared spectroscopy device (ARGES Cerebro, Hemosoft Inc., Turkey) was used to measure the changes in HbO2 and Hb concentrations from 12 healthy volunteers. Partial correlation (PC) values were computed for each stimulus condition. The results of ANOVA test (p<0.05) in HbO2 and Hb signals indicate the bilateral connections between two brain hemispheres. The partial correlation analysis, by removing the common effect of channel interference, offers a suitable measure to evaluate the performance of the prefrontal cortex. Also, the results of partial correlation showed that compared to Hb signal, HbO2 signal is more sensitive to brain activities. This study suggests that fNIRS is a valuable tool for demonstrating the relationship between cortical function in complex cognitive activities.

Pre-stimulus alpha and post-stimulus N2 foreshadow imminent errors in a single task

Performance errors have been attributed to distinct neural mechanisms in different tasks. Two temporally and physiologically dissociable neural patterns prior to errors, i.e., pre-stimulus alpha (8–13Hz) power indicative of sustained attention and post-stimulus N2 amplitude indicative of cognitive control, have been widely (but independently) reported in many studies. However, it is still largely unknown whether these two neural mechanisms for error commission exist in a single task at the same time and, if so, whether they can be probed simultaneously and how they lead to response accuracy (collectively or separately). To this end, we measured high-density electroencephalography (EEG) signals in a color–word matching Stroop task. We quantified both patterns on EEG data from individual stimulus condition (congruent or incongruent), as well as on pooled data from both conditions. Enhanced pre-stimulus alpha power for errors was identified over the parieto-occipital area in the congruent condition and the pooled data. Reduced post-stimulus N2 amplitude was only revealed in the incongruent condition. More importantly, for the first time, a balanced interaction between these two EEG patterns was revealed in correct trials, but not in error trials. These findings suggest that errors in one task could occur due to distinct neural mechanisms, e.g., poor sustained attention, poor cognitive control, or missed balance between these two. The present results further suggest that the detection of neural patterns related to different neural mechanisms could be complicated by other modulation factors, such as stimulus condition. Therefore, more than one neural marker should be simultaneously monitored to effectively predict imminent errors.

Studying hemispheric lateralization during a Stroop task through near-infrared spectroscopy-based connectivity.

ABSTRACT. Near-infrared spectroscopy (NIRS) is a developing and promising functional brain imaging technology. Developing data analysis methods to effectively extract meaningful information from collected data is the major bottleneck in popularizing this technology. In this study, we measured hemodynamic activity of the prefrontal cortex (PFC) during a color-word matching Stroop task using NIRS. Hemispheric lateralization was examined by employing traditional activation and novel NIRS-based connectivity analyses simultaneously. Wavelet transform coherence was used to assess intrahemispheric functional connectivity. Spearman correlation analysis was used to examine the relationship between behavioral performance and activation/functional connectivity, respectively. In agreement with activation analysis, functional connectivity analysis revealed leftward lateralization for the Stroop effect and correlation with behavioral performance. However, functional connectivity was more sensitive than activation for identifying hemispheric lateralization. Granger causality was used to evaluate the effective connectivity between hemispheres. The results showed increased information flow from the left to the right hemispheres for the incongruent versus the neutral task, indicating a leading role of the left PFC. This study demonstrates that the NIRS-based connectivity can reveal the functional architecture of the brain more comprehensively than traditional activation, helping to better utilize the advantages of NIRS.

Positive effect of acute mild exercise on executive function via arousal-related prefrontal activations: An fNIRS study

Despite the practical implication of mild exercise, little is known about its influence on executive function and its neural substrates. To address these issues, the present study examined the effect of an acute bout of mild exercise on executive function and attempted to identify potential neural substrates using non-invasive functional near-infrared spectroscopy (fNIRS). Twenty-five young individuals performed a color-word matching Stroop task (CWST) and a two-dimensional scale to measure changes of psychological mood states both before and after a 10-minute exercise session on a cycle ergometer at light intensity (30% v·o2peak) and, for the control session, without exercise. Cortical hemodynamic changes in the prefrontal area were monitored with fNIRS during the CWST in both sessions. The acute bout of mild exercise led to improved Stroop performance, which was positively correlated with increased arousal levels. It also evoked cortical activations regarding Stroop interference on the left dorsolateral prefrontal cortex and frontopolar area. These activations significantly corresponded with both improved cognitive performance and increased arousal levels. Concurrently, this study provides empirical evidence that an acute bout of mild exercise improves executive function mediated by the exercise-induced arousal system, which intensifies cortical activation in task-related prefrontal sub-regions.

Functional Near Infrared Spectroscopy to Investigation of Functional Connectivity in Schizophrenia Using Partial Correlation

Functional near-infrared spectroscopy (fNIRS) is an optical imaging method which monitors the brain activation by measuring the successive changes in the concentration of oxy- and deoxyhemoglobin in real time. In this study, we aimed to investigate the functional connectivity in the prefrontal cortex (PFC) during a modified version of the color-word matching Stroop task among schizophrenia and healthy persons. fNIRS data were band-pass filtered using a wavelet algorithm with frequency range of 0.003-0.08Hz. Partial correlation (PC) values were computed for each stimulus condition. Our analysis shows that the functional connectivity of PFC is highly relevant with the cognitive load and it is different from healthy to schizophrenia person.

Inhibitory function and working memory in attention deficit/hyperactivity disorder and pervasive developmental disorders: does a continuous cognitive gradient explain ADHD and PDD traits?

To clarify the relationship between attention deficit/hyperactivity disorder (AD/HD) and pervasive developmental disorders (PDD), we investigated the common features and differences of these disorders in neuropsychological profiles. The subjects were 4 groups of Japanese boys aged 6 to 15 years, categorized by diagnosis:AD/HD (n＝20), PDD with comorbid AD/HD (PDD＋:n＝16), PDD without comorbid AD/HD (PDD－:n＝8), and typically developing (n＝60). We evaluated executive function (EF) through verbal and visuospatial memory tasks, the Go/NoGo task, and the color-word matching Stroop task. We performed a categorical analysis to estimate the effects of the 3 disorders on EF and a dimensional analysis to estimate the effects of symptom scales on EF. We found that the AD/HD and PDD＋ subjects had negative effects on verbal working memory and intra-individual response variability. The severity of these impairments was positively correlated with the inattentiveness score. The subjects with a PDD＋ or PDD－ diagnosis had poorer scores on interference control;the severity of this impairment was correlated with the PDD symptom score. Impairments in visuospatial working memory were detected in the AD/HD and PDD－ groups but not in the PDD＋ group. Impairments in inhibition of the pre-potent response were noted in all 3 categories. AD/HD and PDD share neuropsychological features, though each disorder has a specific impairment pattern. Our findings partially support the idea that AD/HD and PDD are on a spectrum.

DETECTING BILATERAL FUNCTIONAL CONNECTIVITY IN THE PREFRONTAL CORTEX DURING A STROOP TASK BY NEAR-INFRARED SPECTROSCOPY

Near-infrared spectroscopy (NIRS) is generally accepted as a functional brain imaging technology for brain activation study. With multichannel highly sensitive NIRS instruments, it has become possible to assess functional connectivity of different brain regions by NIRS. However, the feasibility needs to be validated in complex cognitive activities. In this study, we recorded the hemodynamic activity of the bilateral prefrontal cortex (PFC) during a color-word matching Stroop task. Wavelet transform coherence (WTC) analysis was applied to assess the functional connectivity of all homologous channel pairs within the left/right PFC. Both the behavioral and brain activation results showed significant Stroop effects. The results of WTC analysis revealed that, bilateral functional connectivity was significantly stronger during both the incongruent stimuli and neutral stimuli compared to that of the rest period. It also showed significant Stroop effect. Our findings demonstrate that, NIRS becomes a valuable tool to elucidate the functional connectivity of brain cortex in complex cognitive activities.

Correlation between hemodynamic and electrophysiological signals dissociates neural correlates of conflict detection and resolution in a Stroop task: a simultaneous near-infrared spectroscopy and event-related potential study

Conflict processing is crucial for humans and has been investigated using hemodynamic and electrophysiological measures. However, because most previous research has studied hemodynamic and electrophysiological measures separately, the relationship between these two measures in conflict processing is poorly understood. In our study, we measure near-infrared spectroscopy (NIRS) and event-related potential (ERP) signals simultaneously in a Chinese color-word matching Stroop task and examine the relationship between the conflict-related hemodynamic signal in the prefrontal cortex (PFC) and electrophysiological signal. The results show significant Stroop effects for behavioral, NIRS (oxy-hemoglobin: HbO 2 ), and ERP [N450, late positive complex (LPC)] data. The significant N450 Stroop effect occurs before the behavioral response to incongruent stimuli, while the evident LPC Stroop effect occurs after it, suggesting that only N450 is associated with conflict processing. Additionally, N450 Stroop effects during the early and later phases are negatively correlated with HbO 2 Stroop effects in the left PFC and in the bilateral PFC, respectively. These results suggest that N450 reflects conflict detection and resolution, the left PFC may be involved in conflict detection, and the bilateral PFC is engaged in conflict resolution. Overall, the analysis of the correlation between hemodynamic and electrophysiological signals is useful for studying human brain function.

Relationships between the color-word matching Stroop task and the Go/NoGo task: toward multifaceted assessment of attention and inhibition abilities of children.

Both selective attention and response inhibition can be assessed through the Stroop task and the Go/NoGo task (Go/NoGo). The color-word matching Stroop task (cwmStroop) differs from the traditional Stroop task in ways that make it easy to administer, and it enables the examiners to analyze reaction time. It is expected that the cwmStroop and Go/NoGo tasks will be useful as clinical assessments for children with developmental disorders and in combination with functional magnetic resonance imaging studies. The objectives of this study were to elucidate the pattern of developmental change in cwmStroop scores and Go/NoGo scores and to determine whether and how cwmStroop scores are related to Go/NoGo scores. The subjects consisted of 108 healthy Japanese children aged 6-14 years. We found that cwmStroop and Go/NoGo scores displayed clear developmental changes between 6 and 14 years of age. The children's scores on the 2 tasks followed different developmental courses, however, and the correlation between scores on the two tasks was weak on the whole. These results indicate that the cwmStroop and Go/NoGo tasks tap different aspects of selective attention and response inhibition. Therefore it is expected that the combination of both tests will be useful in the multifaceted assessment of selective attention and response inhibition in childhood.

Acute moderate exercise enhances compensatory brain activation in older adults

A growing number of reports state that regular exercise enhances brain function in older adults. Recently a functional near-infrared spectroscopy (fNIRS) study revealed that an acute bout of moderate exercise enhanced activation of the left dorsolateral prefrontal cortex (L-DLPFC) associated with Stroop interference in young adults. Whether this acute effect is also applicable to older adults was examined. Sixteen older adults performed a color-word matching Stroop task before and after 10 minutes of exercise on a cycle ergometer at a moderate intensity. Cortical hemodynamics of the prefrontal area was monitored with a fNIRS during the Stroop task. We analyzed Stroop interference (incongruent-neutral) as Stroop performance. Though activation for Stroop interference was found in the bilateral prefrontal area before the acute bout of exercise, activation of the right frontopolar area (R-FPA) was enhanced after exercise. In the majority of participants, this coincided with improved performance reflected in Stroop interference results. Thus, an acute bout of moderate exercise improved Stroop performance in older adults, and this was associated with contralateral compensatory activation.

Tackling frontal lobe–related functions in PKU through functional brain imaging: a Stroop task in adult patients

Profound mental retardation in phenylketonuria (PKU) can be prevented by a low phenylalanine (Phe) diet. However, even patients treated early have inconsistently shown deficits in several frontal lobe-related neuropsychological tasks such as the widely accepted Stroop task. The goal of this study was to investigate whether adult patients exhibit altered brain activation in Stroop-related locations in comparison to healthy controls and if an acute increase in blood Phe levels in patients has an effect on activation patterns. Seventeen male, early-treated patients with classic PKU (mean ± SD age: 31.0 ± 5.2years) and 15 male healthy controls (32.1 ± 6.4years) were compared using a color-word matching Stroop task in a functional magnetic resonance imaging (fMRI) study at 3T. Participants were scanned twice, and an oral Phe load (100mg/kg body weight) was administered to patients prior to one of the fMRI sessions (placebo-controlled). Activity in brain regions that are known to be involved in Stroop tasks was assessed. PKU patients exhibited poorer accuracy in incongruent trials. Reaction times were not significantly different. There were no consistent differences in BOLD activations in Stroop-associated brain regions. The oral Phe administration had no significant effect on brain activity. Neither a generally slower task performance nor distinctively altered functioning of brain networks involved in a task representing a subset of dopamine-dependent executive functions could be proven. Decreased accuracy and inconsistent findings in posterior areas necessitate further study of frontal-lobe functioning in PKU patients in larger study samples.

Right prefrontal brain activation due to Stroop interference is altered in attention-deficit hyperactivity disorder — A functional near-infrared spectroscopy study

Attention-deficit hyperactivity disorder is a common finding in school children. Because it was suggested to be related to frontal lobe dysfunction, we hypothesized that brain activation would be altered during an event-related color–word matching Stroop task in comparison to a healthy control group. Twelve medication-free boys suffering from attention-deficit hyperactivity disorder were compared with 12 education- and age-matched healthy boys. As an imaging method we applied functional near-infrared spectroscopy, because it is particularly insensitive to movement artifacts and, accordingly, well suited for studies in children. Generally, the Stroop task led to activations in the lateral prefrontal cortex of both patients and control subjects. Moreover, data suggest that Stroop interference elicited (presumably compensatory) higher oxygen consumption and brain activation in the right dorsolateral prefrontal cortex of boys with attention-deficit hyperactivity disorder. This effect was not confounded by behavioral differences, because boys with attention-deficit hyperactivity disorder showed only a non-specifically increased reaction time in comparison with control subjects. In sum, our results indicate that attention-deficit hyperactivity disorder is characterized by functional impairments of the dorsolateral prefrontal cortex. Our study further establishes functional near-infrared spectroscopy as an imaging tool for studies in neurodevelopment and child and adolescent psychiatry.

On Temporal Connectivity of PFC Via Gauss - Markov Modeling of fNIRS Signals

Functional near-infrared spectroscopy (fNIRS) is an optical imaging method, which monitors the brain activation by measuring the successive changes in the concentration of oxy- and deoxyhemoglobin in real time. In this study, we present a method to investigate the functional connectivity of prefrontal cortex (PFC) Sby applying a Gauss-Markov model to fNIRS signals. The hemodynamic changes on PFC during the performance of cognitive paradigm are measured by fNIRS for 17 healthy adults. The color-word matching Stroop task is performed to activate 16 different regions of PFC. There are three different types of stimuli in this task, which can be listed as incongruent stimulus (IS), congruent stimulus (CS), and neutral stimulus (NS), respectively. We introduce a new measure, called "information transfer metric" (ITM) for each time sample. The behavior of ITMs during IS are significantly different from the ITMs during CS and NS, which is consistent with the outcome of the previous research, which concentrated on fNIRS signal analysis via color-word matching Stroop task. Our analysis shows that the functional connectivity of PFC is highly relevant with the cognitive load, i.e., functional connectivity increases with the increasing cognitive load.