Activity In Dorsolateral Prefrontal Cortex Research Articles

Associations between gait performance and pain intensity, psychosocial factors, executive functions as well as prefrontal cortex activity in chronic low back pain patients: A cross-sectional fNIRS study.

Activities of daily living, such as walking, are impaired in chronic low back pain (CLBP) patients compared to healthy individuals. Thereby, pain intensity, psychosocial factors, cognitive functioning and prefrontal cortex (PFC) activity during walking might be related to gait performance during single and dual task walking (STW, DTW). However, to the best of our knowledge, these associations have not yet been explored in a large sample of CLBP patients. Gait kinematics (inertial measurement units) and PFC activity (functional near-infrared spectroscopy) during STW and DTW were measured in 108 CLBP patients (79 females, 29 males). Additionally, pain intensity, kinesiophobia, pain coping strategies, depression and executive functioning were quantified and correlation coefficients were calculated to determine the associations between parameters. The gait parameters showed small correlations with acute pain intensity, pain coping strategies and depression. Stride length and velocity during STW and DTW were (slightly to moderately) positively correlated with executive function test performance. Specific small to moderate correlations were found between the gait parameters and dorsolateral PFC activity during STW and DTW. Patients with higher acute pain intensity and better coping skills demonstrated slower and less variable gait, which might reflect a pain minimization strategy. Psychosocial factors seem to play no or only a minor role, while good executive functions might be a prerequisite for a better gait performance in CLBP patients. The specific associations between gait parameters and PFC activity during walking indicate that the availability and utilization of brain resources are crucial for a good gait performance.

Neural Responses to a Working Memory Task in Acute Depressed and Remitted Phases in Bipolar Patients.

(1) Cognitive impairments such as working memory (WM) deficits are amongst the most common dysfunctions characterizing bipolar disorder (BD) patients, severely contributing to functional impairment. We aimed to investigate WM performance and associated brain activation during the acute phase of BD and to observe changes in the same patients during remission. (2) Frontal brain activation was recorded using functional near-infrared spectroscopy (fNIRS) during n-back task conditions (one-back, two-back and three-back) in BD patients in their acute depressive (n = 32) and remitted (n = 15) phases as well as in healthy controls (n = 30). (3) Comparison of BD patients during their acute phase with controls showed a trend (p = 0.08) towards lower dorsolateral prefrontal cortex (dlPFC) activation. In the remitted phase, BD patients showed lower dlPFC and ventrolateral prefrontal cortex (vlPFC) activation (p = 0.02) compared to controls. No difference in dlPFC and vlPFC activation between BD patients' phases was found. (4) Our results showed decreased working memory performance in BD patients during the working memory task in the acute phase of disease. Working memory performance improved in the remitted phase of the disease but was still particularly attenuated for the more demanding conditions.

Functional MRI of inhibitory control processing in problematic mobile video gamers

With the development of mobile technology, mobile video games provide people with a more convenient way of entertainment, but problematic playing could also bring some negative consequences. Prior studies have indicated that Internet gaming addicts were accompanied by impaired inhibitory control. However, as a relatively new form of problematic game usage based on mobile devices, little is known about the neurobiological underpinnings of inhibitory control in problematic mobile video game (PMVG) users. Adopting an event-related fMRI Stroop task, the present study aimed to examine the different neural correlates of inhibitory control between PMVG and healthy control (HC) subjects. Compared with HC group, PMVG group showed greater brain activities in the right dorsolateral prefrontal cortex (DLPFC) during the Stroop process. Moreover, correlation analysis showed that brain activities extracted from the voxel in the DLPFC cluster had a significantly negative correlation with reward sensitivity. Our current findings may suggest the compensating effect in key brain regions of inhibitory control in problematic mobile video gamers relative to healthy controls.

Modulation of the executive control network by anodal tDCS over the left dorsolateral prefrontal cortex improves task shielding in dual tasking

Task shielding is an important executive control demand in dual-task performance enabling the segregation of stimulus–response translation processes in each task to minimize between-task interference. Although neuroimaging studies have shown activity in left dorsolateral prefrontal cortex (dlPFC) during various multitasking performances, the specific role of dlPFC in task shielding, and whether non-invasive brain stimulation (NIBS) may facilitate task shielding remains unclear. We therefore applied a single-blind, crossover sham-controlled design in which 34 participants performed a dual-task experiment with either anodal transcranial direct current stimulation (atDCS, 1 mA, 20 min) or sham tDCS (1 mA, 30 s) over left dlPFC. Task shielding was assessed by the backward-crosstalk effect, indicating the extent of between-task interference in dual tasks. Between-task interference was largest at high temporal overlap between tasks, i.e., at short stimulus onset asynchrony (SOA). Most importantly, in these conditions of highest multitasking demands, atDCS compared to sham stimulation significantly reduced between-task interference in error rates. These findings extend previous neuroimaging evidence and support modulation of successful task shielding through a conventional tDCS setup with anodal electrode over the left dlPFC. Moreover, our results demonstrate that NIBS can improve shielding of the prioritized task processing, especially in conditions of highest vulnerability to between-task interference.

277. Reductions in Cue-Induced Craving are Associated With Reductions in Dorsolateral Prefrontal Cortex Activation in Absence of Heavy Drinking During Cognitive Behavioral Therapy for Alcohol Use Disorder

277. Reductions in Cue-Induced Craving are Associated With Reductions in Dorsolateral Prefrontal Cortex Activation in Absence of Heavy Drinking During Cognitive Behavioral Therapy for Alcohol Use Disorder

Functional brain changes in sarcopenia: evidence for differential central neural mechanisms in dynapenic older women

BackgroundThe European Working Group on Sarcopenia in Older People (EWGSOP2) recently revised its definition and diagnostic criteria for sarcopenia, placing muscle strength at the forefront. The pathogenesis of dynapenia (or low muscle strength) is still not fully understood, but there is emerging evidence that central neural factors constitute critical determinants.MethodsOur cross-sectional study included 59 community-dwelling older women (mean age 73.1 ± 4.9 years). Participants underwent detailed skeletal muscle assessments for muscle strength defined by handgrip strength and chair rise time measurements using the recently published EWGSOP2 cut-off points. Functional magnetic resonance imaging (fMRI) was assessed during the performance of a cognitive dual-task paradigm, consisting of a baseline, two single-tasks (motor and arithmetic) and one dual-task (motor and arithmetic combined).ResultsForty-seven percent (28/59) of participants were classified as dynapenic. fMRI results revealed a differential recruitment of motor circuits in the brain during the dual-task condition in dynapenic as compared with non-dynapenic participants. In particular, while the brain activity during the single-tasks did not differ between the two groups, only during the dual-task non-dynapenic participants showed significant increased activation in dorsolateral prefrontal and premotor cortex, and in supplementary motor area as compared to dynapenic participants.ConclusionOur results point to a dysfunctional involvement of brain networks associated with motor control in dynapenia in a multi-tasking paradigm. A better knowledge of the link between dynapenia and brain functions could provide new impulses in the diagnosis and interventions for sarcopenia.

Differential neural processing of value during decision-making in adults with attention-deficit/hyperactivity disorder and healthy controls.

Risk-taking behaviours are observed among adults with attention-deficit/hyperactivity disorder (ADHD). We sought to evaluate altered neural processing of stimuli values associated with risk-taking decision behaviour, distinct from learning requirements, among adults with ADHD. Overall, 32 adults with ADHD and 32 healthy controls without ADHD underwent a lottery choice task in a functional magnetic resonance imaging (fMRI) experiment. Participants accepted or rejected stakes with explicit information about variable probabilities of winning or losing points at different magnitudes. Outcomes were independent across trials, circumventing reward learning. Data analysis explored group differences in neurobehavioural responses to stimuli values during choice decision-making processing and outcome feedback. Compared with healthy controls, adults with ADHD had slower response times and tended to accept more stakes with a middle-to-low probability of winning. Adults with ADHD had evidence of lower dorsolateral prefrontal cortex (DLPFC) activity and reduced sensitivity in the ventromedial prefrontal cortex (VMPFC) region of interest in response to linear changes in probability, compared with healthy controls. Lower DLPFC responses were associated with lower VMPFC probability sensitivity and greater risk-taking among healthy controls but not adults with ADHD. Compared with health controls, adults with ADHD showed higher responses to loss outcomes in the putamen and hippocampus. Assessments of real-life decision behaviours are required to further validate the experimental findings. Our findings explore tonic and phasic neural processing of value-related information that modulates risk-taking behaviours among adults with ADHD. Dysregulated neural computation of the values of behavioural actions and outcomes in the frontostriatal circuits may underlie decision processing distinct from reward learning differences among adults with ADHD. NCT02642068.

The cognitive control mechanism of improving emotion regulation: A high-definition tDCS and ERP study

BackgroundCognitive reappraisal as a commonly used emotion regulation strategy includes reinterpretation and detachment and is associated with the activity of the dorsolateral prefrontal cortex (DLPFC). However, the neuroenhancement mechanisms of transcranial direct current stimulation (tDCS) over DLPFC that modulate cognitive reappraisal are not yet fully understood. This work aims to verify the causal role of DLPFC in different tactics of cognitive reappraisal and further explore the cognitive control mechanisms of emotion regulation. MethodsA single-blind, within-subjects, sham-controlled design was adopted. Twenty-nine healthy subjects underwent two sessions of offline high-definition tDCS (HD-tDCS) that were targeted at the right DLPFC. Participants completed the cognitive control (Flanker) and cognitive reappraisal task in each session. We quantified the efficacy of cognitive control using N2 and P3 of the evoked brain responses and cognitive reappraisal using the late positivity potential (LPP). ResultsAnodal HD-tDCS resulted in the decrease of LPP for reinterpretation and detachment. The cognitive control increased after stimulation, indicated by the increase of P3 and decrease of N2 amplitude. The increased cognitive control mediated the effect of HD-tDCS on modulating reinterpretation, but not for detachment. LimitationsThe single-blind design, absence of the lasting-effects measure, and the intrinsically limited focality of tDCS are limitations of this study. ConclusionsIncreasing the activity of DLPFC would facilitate emotion regulation and increase cognitive control. Cognitive control may be a significant potential mechanism for reinterpretation. Both tDCS and cognitive control interventions may be possible approaches to enhance emotion regulation.

The immediate effects of iTBS on the muscle activation pattern under challenging balance conditions in the patients with chronic low back pain: A preliminary study.

The patients with chronic low back pain (CLBP) showed impaired postural control, especially in challenging postural task. The dorsolateral prefrontal cortex (DLPFC) is reported to involve in the complex balance task, which required considerable attentional control. The effect of intermittent theta burst stimulation (iTBS) over the DLPFC to the capacity of postural control of CLBP patients is still unknown. Participants diagnosed with CLBP received a single-session iTBS over the left DLPFC. All the participants completed the postural control tasks of single-leg (left/right) standing before and after iTBS. The activation changes of the DLPFC and M1 before and after iTBS were recorded by functional near-infrared spectroscopy (fNIRS). The activation pattern of the trunk [transversus abdominis (TrA), superficial lumbar multifidus (SLM)] and leg [tibialis anterior (TA), gastrocnemius medialis (GM)] muscles including root mean square (RMS) and co-contraction index (CCI) during single-leg standing were measured by surface electromyography (sEMG) before and after the intervention. The paired t-test was used to test the difference before and after iTBS. Pearson correlation analyses were performed to test the relationship between the oxyhemoglobin concentration and sEMG outcome variables (RMS and CCI). Overall, 20 participants were recruited. In the right-leg standing condition, compared with before iTBS, the CCI of the right TrA/SLM was significantly decreased (t = -2.172, p = 0.043), and the RMS of the right GM was significantly increased (t = 4.024, p = 0.001) after iTBS. The activation of the left DLPFC (t = 2.783, p = 0.012) and left M1 (t = 2.752, p = 0.013) were significantly decreased and the relationship between the left DLPFC and M1 was significant after iTBS (r = 0.575, p = 0.014). Correlation analysis showed the hemoglobin concentration of M1 was negatively correlated with the RMS of the right GM (r = -0.659, p = 0.03) and positively correlated between CCI of the right TrA/SLM (r = 0.503, p = 0.047) after iTBS. There was no significant difference in the brain or muscle activation change in the left leg-standing condition between before and after iTBS. Intermittent theta burst stimulation over the left DLPFC seems to be able to improve the muscle activation pattern during postural control ability in challenging postural task, which would provide a new approach to the treatment of CLBP.

Changes in neural responses during affective and non-affective tasks and improvement of posttraumatic stress disorder symptoms following trauma-focused psychotherapy

At least one-third posttraumatic stress disorder (PTSD) patients do not respond to trauma-focused psychotherapy (TF-psychotherapy), which is the treatment of choice for PTSD. To clarify the change mechanisms that may be associated with treatment response, this study examined changes in neural activations during affective and non-affective processing that occur with improvement of symptoms after TF-psychotherapy. This study assessed PTSD treatment-seeking patients (n = 27) prior to and after TF-psychotherapy using functional magnetic resonance imaging when they completed three tasks: (a) passive viewing of affective faces, (b) cognitive reappraisal of negative images, and (c) non-affective response inhibition. Patients then underwent 9 sessions of TF-psychotherapy, and were assessed on the Clinician-Administered PTSD Scale following treatment. Changes in neural responses in affect and cognitive processing regions-of-interest for each task were correlated with reduction of PTSD severity from pretreatment to posttreatment in the PTSD cohort. Data from 21 healthy controls was used for comparison. Improvement of symptoms in PTSD were associated with increased activation of left anterior insula, reductions in the left hippocampus and right posterior insula during viewing of supraliminally presented affective images, and reduced connectivity between the left hippocampus with the left amygdala and rostral anterior cingulate. Treatment response was also associated with reduced activation in the left dorsolateral prefrontal cortex during reappraisal of negative images. There were no associations between response and activation change during response inhibition. This pattern of findings indicates that improvement of PTSD symptoms following TF-psychotherapy is associated with changes in affective rather than non-affective processes. These findings accord with prevailing models that TF-psychotherapy promotes engagement and mastery of affective stimuli.Clinical Trials Registration: Trial Registration: Prospectively registered at Australian and New Zealand Clinical Trials Registry, ACTRN12612000185864 and ACTRN12609000324213. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=83857

TDCS Anodal Stimulation of the Right Dorsolateral Prefrontal Cortex Improves Creative Performance in Real-World Problem Solving

Brain regions associated with creativity is a focal point in research related to the field of cognitive neuroscience. Previous studies have paid more attention to the role of activation of the left dorsolateral prefrontal cortex in creativity tasks, which are mostly abstract conceptual tasks, and less attention to real-world creativity tasks. The right dorsolateral prefrontal cortex is involved in functions such as visuospatial processing, which may have a positive impact on innovative solutions to real-world problems. In this study, tDCS technology was used to explore the effect of anodal stimulation of the right dorsolateral prefrontal cortex on design creativity performance in a real-word problem-solving task related to product design. The experimental task comprised three stages, of which the first two were idea generation stages based on divergent thinking using text and graphics, respectively, whereas the third was the creative evaluation stage based on convergent thinking. Thirty-six design students were recruited to partake in the experiment. They were randomly assigned into anodal stimulation and sham stimulation groups. The results showed that anodal stimulation of the right dorsolateral prefrontal cortex produced a significant positive effect during the creative evaluation stage, promoting the usefulness of ideas (p = 0.009); thus, improving product creativity scores. However, there was no significant impact on the idea generation stage (p > 0.05), which is dominated by divergent thinking. The results suggest that activating the right dorsolateral prefrontal cortex with tDCS can improve people's performance in creative activities by promoting convergent thinking rather than divergent thinking. It also provides further evidence that the right hemisphere of the brain has an advantage in solving complex problems that require the participation of visuospatial information.

Effects of dance video game training on cognitive functions of community-dwelling older adults with mild cognitive impairment

Some patients with minor cognitive impairment can revert to normal cognition if intervention is implemented early. Dance video games as multi-task training have shown beneficial effects on cognitive and physical functions in older adults. This study aimed to elucidate the effects of dance video game training on cognitive functions and prefrontal cortex activity in older adults with and without mild cognitive impairment. A single-arm trial was used for this study. The participants were divided based on the Japanese version of Montreal Cognitive Assessment scores into the mild cognitive impairment (n = 10) and normal cognitive function (n = 11) groups. Dance video game training was performed 60min/day, 1day/week, for a total of 12weeks. Neuropsychological assessments, prefrontal cortex activity using functional near-infrared spectroscopy, and step performance of dance video game were recorded at pre- and post-intervention. Dance video game training significantly improved the Japanese version of Montreal Cognitive Assessment score (p < 0.05), and tendency toward improvement was observed in the trail making test in the mild cognitive impairment group. The dorsolateral prefrontal cortex activity in the Stroop color word test was significantly increased in the mild cognitive impairment group (p < 0.05) after dance video game training. Dance video game training improved cognitive function and increased prefrontal cortex activity in the mild cognitive impairment group.

A Brief History of Transcranial Magnetic Stimulation

A Brief History of Transcranial Magnetic Stimulation

Resting-state brain activity dysfunctions in schizophrenia and their associations with negative symptom domains

IntroductionNegative symptoms represent a fundamental aspect of schizophrenia: they have a substantial impact on patients’ real-life functioning and do not respond satisfactorily to currently available treatments. Therefore, a better understanding of the pathophysiological mechanisms underlying these symptoms could favor the development of new treatments.To date, the most validated pathophysiological hypothesis indicates an association between the Motivational domain (consisting of avolition, anhedonia and asociality) and alterations in the neuronal circuits involved in motivation. The Expressive Deficit domain (consisting of blunted affect and alogia) would be subtended by widespread alterations of cortical connectivity and associated with impaired neurocognition, social cognition, and the presence of neurological soft signs.ObjectivesThe aim of the present study is to examine the neurobiological correlates of the two domains of negative symptoms, starting from the brain areas that have been most commonly found in the literature to be associated with negative symptoms.MethodsResting-state (rs) fMRI data were acquired in 62 subjects with schizophrenia (SZ) and 46 healthy controls (HC). The two negative symptom domains were assessed using the Brief Negative Symptom Scale. In addition, the following assessment tools were used: the Positive and Negative Syndrome Scale for the assessment of positive symptoms and disorganization, the Calgary Depression Scale for Schizophrenia for depression and the St. Hans Rating Scale for extrapyramidal symptoms. The study of the possible relationships between rs-brain activity and the negative symptoms domains was conducted through partial correlations, checking for possible confounding factors (positive, depressive, extrapyramidal symptoms and disorganization).ResultsThe SZ, compared to the HC, showed higher rs-brain activity of the right inferior parietal lobule and of the right temporoparietal junction and lower rs-brain activity of the right dorsolateral prefrontal cortex, bilateral anterior dorsal cingulate cortex, bilateral ventral caudate and bilateral dorsal caudate. Furthermore, in the group of patients, the rs-brain activity of the left ventral caudate showed a moderate negative correlation with the Expressive deficit domain (r = -0.401; p = 0.003), but not with the Motivational domain.ConclusionsThe results of the present study, in line with the literature, demonstrated how the two domains of negative symptomatology are subtended by different pathophysiological mechanisms. Given the role played by the ventral caudate in neurocognitive processes, these results are in line with the hypothesis that Expressive deficit may have a common etiopathogenesis with cognitive deficits. A better understanding of the neurobiology of negative symptoms could foster the development of innovative treatment strategies targeting the two negative symptom domains.Disclosure of InterestNone Declared

Abnormal Prefrontal Brain Activation During a Verbal Fluency Task in Treatment-Resistant Depression Using Near-Infrared Spectroscopy.

The study investigated cognitive performance and brain function between treatment-resistant depression (TRD) and non- TRD patients to find potential neurobiological markers associated with refractoriness in depression patients. Fourteen TRD patients, 26 non-TRD patients and 23 healthy controls (HC) were included in the present study. The neural function of prefrontal cortex (PFC) and cognitive performance among the three group were examined using near-infrared spectroscopy (NIRS) during verbal fluency task (VFT). Both TRD and non-TRD groups exhibited significantly worse VFT performance and lower activation of oxygenated hemoglobin (oxy-Hb) changes in the bilateral dorsolateral PFC (DLPFC) compared to the HC group. Within the TRD and non-TRD groups, VFT performance was no significant difference, but activation of oxy-Hb changes in dorsomedial PFC (DMPFC) in TRD patients was significantly lower than non-TRD patients. In addition, activation of oxy-Hb changes in right DLPFC were negatively correlated with the severity of depressive symptoms in depression patients. Both TRD patients and non-TRD patients exhibited lower oxy-Hb activation in DLPFC. TRD patients exhibit lower oxy- Hb activation in DMPFC than non-TRD patients. fNIRS maybe a useful tool for predict depressive patients with or without treatment resistant.

Altered frontoparietal activity in acoustic startle priming tasks during reticulospinal tract facilitation: An fNIRS study.

Because it is one of the important pathways for promoting motor recovery after cortical injury, the function of the reticulospinal tract (RST) has received increasing attention in recent years. However, the central regulatory mechanism of RST facilitation and reduction of apparent response time is not well understood. To explore the potential role of RST facilitation in the acoustic startle priming (ASP) paradigm and observe the cortical changes induced by ASP reaching tasks. Twenty healthy participants were included in this study. The reaching tasks were performed with their left and right hands. Participants were instructed to get ready after the warning cue and complete the reach as soon as they heard the Go cue. Half of the testing trials were set as control trials with an 80-dB Go cue. The other half of the trials had the Go cue replaced with 114-dB white noise to evoke the StartleReact effect, inducing reticulospinal tract facilitation. The response of the bilateral sternocleidomastoid muscle (SCM) and the anterior deltoid was recorded via surface electromyography. Startle trials were labeled as exhibiting a positive or negative StartleReact effect, according to whether the SCM was activated early (30-130 ms after the Go cue) or late, respectively. Functional near-infrared spectroscopy was used to synchronously record the oxyhemoglobin and deoxyhemoglobin fluctuations in bilateral motor-related cortical regions. The β values representing cortical responses were estimated via the statistical parametric mapping technique and included in the final analyses. Separate analyses of data from movements of the left or right side revealed significant activation of the right dorsolateral prefrontal cortex during RST facilitation. Moreover, left frontopolar cortex activation was greater in positive startle trials than in control or negative startle trials during left-side movements. Furthermore, decreased activity of the ipsilateral primary motor cortex in positive startle trials during ASP reaching tasks was observed. The right dorsolateral prefrontal cortex and the frontoparietal network to which it belongs may be the regulatory center for the StartleReact effect and RST facilitation. In addition, the ascending reticular activating system may be involved. The decreased activity of the ipsilateral primary motor cortex suggests enhanced inhibition of the non-moving side during the ASP reaching task. These findings provide further insight into the SE and into RST facilitation.

Changes in cortical activation during upright stance in individuals with chronic low back pain: An fNIRS study.

Postural control deficits are a potential cause of persistent and recurrent pain in patients with chronic low back pain (CLBP). Although some studies have confirmed that the dorsolateral prefrontal cortex (DLPFC) contributes to pain regulation in CLBP, its role in the postural control of patients with CLBP remains unclear. Therefore, this study aimed to investigate the DLPFC activation of patients with CLBP and healthy controls under different upright stance task conditions. Twenty patients with CLBP (26.50 ± 2.48 years) and 20 healthy controls (25.75 ± 3.57 years) performed upright stance tasks under three conditions: Task-1 was static balance with eyes open; Task-2 was static balance with eyes closed; Task-3 involved dynamic balance on an unstable surface with eyes open. A wireless functional near-infrared spectroscopy (fNIRS) system measured cortical activity, including the bilateral DLPFC, pre-motor cortex (PMC) and supplementary motor area (SMA), the primary motor cortex (M1), the primary somatosensory cortex (S1), and a force platform measured balance parameters during upright stance. The two-way repeated measures ANOVA results showed significant interaction in bilateral PMC/SMA activation. Moreover, patients with CLBP had significantly increased right DLPFC activation and higher sway 32 area and velocity than healthy controls during upright stance. Our results imply that PMC/SMA and DLPFC maintain standing balance. The patients with CLBP have higher cortical activity and upright stance control deficits, which may indicate that the patients with CLBP have low neural efficiency and need more motor resources to maintain balance.

Involvement of the prefrontal cortex in motor sequence learning: A functional near-infrared spectroscopy (fNIRS) study

Our previous functional near-infrared spectroscopy (fNIRS) study on motor sequence learning (Polskaia et al., 2020) did not detect the same decrease in activity in the left dorsolateral prefrontal cortex (DLPFC) associated with movement automaticity, as reported by Wu et al. (2004). This was partly attributed to insufficient practice time to reach neural efficiency. Therefore, we sought to expand on our previous work to better understand the contribution of the prefrontal cortex (PFC) to motor sequence learning by examining learning across a longer period of time. Participants were randomly assigned to one of two groups: control or trained. fNIRS was acquired at three time points: pre-test, post-test, and retention. Participants performed four sequences (S1, S2, S3, and S4) of right-hand finger tapping. The trained group also underwent four days of practice of S1 and S2. No group differences in the left DLPFC and ventrolateral (VLPFC) were found between sessions for S1 and S2. Our findings revealed increased contribution from the right VLPFC in post-test for the trained group, which may reflect the active retrieval of explicit information from long-term memory. Our results suggest that despite additional practice time, explicit motor sequence learning requires the continued involvement of the PFC.

Resting-State Brain Activity Dysfunctions in Schizophrenia and Their Associations with Negative Symptom Domains: An fMRI Study.

The aim of the present study was to examine the neurobiological correlates of the two negative symptom domains of schizophrenia, the Motivational Deficit domain (including avolition, anhedonia, and asociality) and the Expressive Deficit domain (including blunted affect and alogia), focusing on brain areas that are most commonly found to be associated with negative symptoms in previous literature. Resting-state (rs) fMRI data were analyzed in 62 subjects affected by schizophrenia (SZs) and 46 healthy controls (HCs). The SZs, compared to the HCs, showed higher rs brain activity in the right inferior parietal lobule and the right temporoparietal junction, and lower rs brain activity in the right dorsolateral prefrontal cortex, the bilateral anterior dorsal cingulate cortex, and the ventral and dorsal caudate. Furthermore, in the SZs, the rs brain activity in the left orbitofrontal cortex correlated with negative symptoms (r = -0.436, p = 0.006), in particular with the Motivational Deficit domain (r = -0.424, p = 0.002), even after controlling for confounding factors. The left ventral caudate correlated with negative symptoms (r = -0.407, p = 0.003), especially with the Expressive Deficit domain (r = -0.401, p = 0.003); however, these results seemed to be affected by confounding factors. In line with the literature, our results demonstrated that the two negative symptom domains might be underpinned by different neurobiological mechanisms.

Enhancement of Visuospatial Working Memory by Transcranial Direct Current Stimulation on Prefrontal and Parietal Cortices.

Previous studies have reported dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC) activation during the performance of spatial working memory (SWM), therefore this study aims to compare the effect of transcranial direct current stimulation (tDCS) between these two areas. Fifty-four healthy right-handed students (27 women, 27 men; age=24.3±0.2 years) were randomly assigned to an anodal group (n=27) and a sham group (n=27), each of these groups was divided into F4 (representing right DLPFC) or P4 (representing right PPC) subgroups, respectively. A computerized Corsi block tapping (CBT) task was used to measure SWM. The tDCS intervention consisted of five daily sessions with a direct current of 1.5 mA for 15 minutes on the F4 or P4 area of the brain at 24-hour intervals. Significant enhancement of the SWM span as well as a faster response was observed after anodal tDCS in both the anterior and posterior direction. Moreover, stimulation of the left DLPFC induced a faster reaction time compared to the right PPC. Stimulation DLPFC and PPC, as an element of the frontoparietal network, showed SWM enhancement, with the DLPFC being more affected. Our finding provides new evidence to compare the effect of stimulation on the two main activated cortical areas during visual SWM.