Brain mGlu5 is linked to cognition and cigarette smoking but does not differ from control in early abstinence from chronic methamphetamine use.

BACKGROUND: The group-I metabotropic glutamate receptor subtype five (mGlu5) has been implicated in methamphetamine exposure in animals, and in human cognition. Because people with Methamphetamine Use Disorder (MUD) exhibit cognitive deficits, we evaluated mGlu5 in people with MUD and controls and tested its association with cognitive performance. METHODS: Positron emission tomography was performed to measure the total volume of distribution (VT) of [18F]FPEB, a radiotracer for mGlu5, in brains of participants with MUD (abstinent from methamphetamine for at least two weeks, n = 14) and a control group (n = 14). Drug use history questionnaires and tests of verbal learning, spatial working memory, and executive function were administered. Associations of VT with methamphetamine use, tobacco use, and cognitive performance were tested. RESULTS: MUD participants did not differ from controls in global or regional VT, and measures of methamphetamine use were not correlated with VT. VT was significantly higher globally in nonsmoking vs. smoking participants (main effect, p = 0.0041). MUD participants showed nonsignificant weakness on the Rey Auditory Verbal Learning Task (RAVLT) and the Stroop Test vs. controls (p = 0.08 and p = 0.13, respectively) with moderate to large effect sizes, and significantly underperformed controls on the SCAP (p = 0.015). Across groups, RAVLT performance correlated with VT in the dorsolateral prefrontal cortex (DLPFC) and superior frontal gyrus. CONCLUSION: Abstinent MUD patients show no evidence of mGlu5 downregulation in brain, but association of VT in dlPFC with verbal learning suggests that medications that target mGlu5 may improve cognitive performance.

Chronic neuropathic pain components in whiplash-associated disorders correlate with metabolite concentrations in the anterior cingulate and dorsolateral prefrontal cortex: a consensus-driven MRS re-examination.

Introduction: Whiplash injury (WHI) is characterised by a forced neck flexion/extension, which frequently occurs after motor vehicle collisions. Previous studies characterising differences in brain metabolite concentrations and correlations with neuropathic pain (NP) components with chronic whiplash-associated disorders (WAD) have been demonstrated in affective pain-processing areas such as the anterior cingulate cortex (ACC). However, the detection of a difference in metabolite concentrations within these cortical areas with chronic WAD pain has been elusive. In this study, single-voxel magnetic resonance spectroscopy (MRS), following the latest MRSinMRS consensus group guidelines, was performed in the anterior cingulate cortex (ACC), left dorsolateral prefrontal cortex (DLPFC), and occipital cortex (OCC) to quantify differences in metabolite concentrations in individuals with chronic WAD with or without neuropathic pain (NP) components. Materials and methods: Healthy individuals (n = 29) and participants with chronic WAD (n = 29) were screened with the Douleur Neuropathique 4 Questionnaire (DN4) and divided into groups without (WAD-noNP, n = 15) or with NP components (WAD-NP, n = 14). Metabolites were quantified with LCModel following a single session in a 3 T MRI scanner within the ACC, DLPFC, and OCC. Results: Participants with WAD-NP presented moderate pain intensity and interference compared with the WAD-noNP group. Single-voxel MRS analysis demonstrated a higher glutamate concentration in the ACC and lower total choline (tCho) in the DLPFC in the WAD-NP versus WAD-noNP group, with no intergroup metabolite difference detected in the OCC. Best fit and stepwise multiple regression revealed that the normalised ACC glutamate/total creatine (tCr) (p = 0.01), DLPFC n-acetyl-aspartate (NAA)/tCr (p = 0.001), and DLPFC tCho/tCr levels (p = 0.02) predicted NP components in the WAD-NP group (ACC r 2 = 0.26, α = 0.81; DLPFC r 2 = 0.62, α = 0.98). The normalised Glu/tCr concentration was higher in the healthy than the WAD-noNP group within the ACC (p < 0.05), but not in the DLPFC or OCC. Neither sex nor age affected key normalised metabolite concentrations related to WAD-NP components when compared to the WAD-noNP group. Discussion: This study demonstrates that elevated glutamate concentrations within the ACC are related to chronic WAD-NP components, while higher NAA and lower tCho metabolite levels suggest a role for increased neuronal-glial signalling and cell membrane dysfunction in individuals with chronic WAD-NP components.

Dance of two brains: Interval subdivision in alternated condition enhances resistance to interference by others.

The accomplishment of interpersonal sensorimotor synchronization is a challenging endeavor because it requires the achievement of a balance between accurate temporal control within individuals and smooth communication between them. This raises a critical question: How does the brain comprehend and process the perceptual information of others to guarantee accurate temporal control of action goals in a social context? A joint synchronization - continuation tapping task was conducted together with varying relative phases (0°/180°) and intervals of tempos (400 ms/800 ms/1600 ms) while neural data was collected using fNIRS (functional near-infrared spectroscopy). Individuals showed better behavioral performance and greater interpersonal brain synchronization(IBS) in the left dorsolateral prefrontal cortex at alternated condition (180° relative phase) compared to symmetric condition (0° relative phase), suggesting that the individual can better maintain behavioral performance and show improved IBS when the partner taps between the individual's gaps. Meanwhile, in most levels of alternated condition, IBS is inversely proportional to interference from partner, implying the counteraction of IBS against interference from others. In addition, when the interval of tempo was 1600 ms, behavioral performance showed a sharp decline, accompanied by a decrease in IBS, reflecting that IBS in SMS reflects effective information exchange between individuals rather than ineffective interference with each other. This study provides insight into the mechanisms underlying sensorimotor synchronization between individuals.

Feasibility and Tolerability of Daily Theta Burst Stimulation in Autistic Youth with Intellectual Disabilities and Minimally Speaking Status: A Pilot Double-Blind Randomized Sham-Controlled Trial.

Scarce clinical trials involving autistic people with intellectual disability (ID) and minimally speaking (MS) status have been a substantial unmet research need in the field. Although earlier studies have demonstrated the feasibility and beneficial potentials of repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex (DLPFC) in intellectually able autistic people, the feasibility and tolerability of applying rTMS in autistic people with ID/MS has never been studied. We conducted the world-first 4-week randomized, double-blind, sham-controlled pilot trial to investigate the feasibility, tolerability, and safety of intermittent theta burst stimulation (iTBS, a variant of excitatory rTMS) over the left DLPFC in autistic youth with ID/MS. 25 autistic youth with ID/MS (aged 8-30 years) were randomized to a 20-session 4-week daily iTBS (n = 13) vs. sham stimulation (n = 12) with follow-up 4 and 8 weeks, respectively, after the last stimulation. A retention rate was 100% in our study. Adverse events of local pain (38%) and dizziness (8%) were only noted in the active group. All adverse events were mild and transient. There were no seizures, new behavioral problems, or other severe/serious adverse events noted. No participants dropped out due to adverse events. With a small sample size, we did not find any beneficial signal of DLPFC iTBS. Our pilot data suggest regular daily TBS treatment for four weeks is feasible, well tolerated and safe in autistic youth with ID/MS. Future randomized controlled trials with sufficiently powered samples are needed to investigate the beneficial potential of rTMS/TBS for autistic people with ID/MS.

Analgesia of noninvasive electrical stimulation of the dorsolateral prefrontal cortex: A systematic review and meta-analysis.

OBJECTIVE: The dorsolateral prefrontal cortex (DLPFC) is implicated in pain modulation, suggesting its potential as a therapeutic target for pain relief. However, studies on transcranial electrical stimulation (tES) over the DLPFC yielded diverse results, likely due to differences in stimulation protocols or pain assessment methods. This study aims to evaluate the analgesic effects of DLPFC-tES using a meta-analytical approach. METHODS: A meta-analysis of 29 studies involving 785 participants was conducted. The effects of genuine and sham DLPFC-tES on pain perception were examined in healthy individuals and patients with clinical pain. Subgroup analyses explored the impact of stimulation parameters and pain modalities. RESULTS: DLPFC-tES did not significantly affect pain outcomes in healthy populations but showed promise in reducing pain-intensity ratings in patients with clinical pain (Hedges' g = -0.78, 95% CI = [-1.33, -0.24], p = 0.005). Electrode placement significantly influenced the analgesic effect, with better results observed when the anode was at F3 and the cathode at F4. CONCLUSIONS: DLPFC-tES holds potential as a cost-effective pain management option, particularly for clinical populations. Optimizing electrode placement, especially with an symmetrical configuration, may enhance therapeutic efficacy. These findings underscore the promise of DLPFC-tES for alleviating perceived pain intensity in clinical settings, emphasizing the importance of electrode placement optimization.

Effect of Low-Intensity Transcranial Focused Ultrasound Stimulation in Patients With Major Depressive Disorder: A Randomized, Double-Blind, Sham-Controlled Clinical Trial.

OBJECTIVE: Low-intensity transcranial focused ultrasound (tFUS) has emerged as a promising non-invasive brain stimulation modality with high spatial selectivity and the ability to reach deep brain areas. The present study aimed to investigate the safety and effectiveness of low-intensity tFUS in treating major depressive disorder. METHODS: Participants were recruited in an outpatient clinic and randomly assigned to either the verum tFUS or sham stimulation group. The intervention group received six sessions of tFUS stimulation to the left dorsolateral prefrontal cortex over two weeks. Neuropsychological assessments were conducted before and after the sessions. Resting-state functional magnetic resonance imaging (rsfMRI) was also performed to evaluate changes in functional connectivity (FC). The primary outcome measure was the change in depressive symptoms, assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS). RESULTS: The tFUS stimulation sessions were well tolerated without any undesirable side effects. The analysis revealed a significant main effect of session sequence on the MADRS scores and significant interactions between the session sequences and groups. The rsfMRI analysis showed a higher FC correlation between the right superior part of the subgenual anterior cingulate cortex (sgACC) and several other brain regions in the verum group compared with the sham group. CONCLUSION: Our results reveal that tFUS stimulation clinically improved MADRS scores with network-level modulation of a sgACC subregion. This randomized, sham-controlled clinical trial, the first study of its kind, demonstrated the safety and probable efficacy of tFUS stimulation for the treatment of depression.

Transcranial direct current stimulation improves tardive dyskinesia in long-term hospitalized patients with chronic schizophrenia.

OBJECTIVE: This study aimed to evaluate the efficacy and safety of transcranial direct current stimulation (tDCS) in chronic schizophrenia patients with tardive dyskinesia (TD) who were long-term hospitalized. METHODS: Sixty-four inpatients who met the DSM-IV diagnostic criteria for schizophrenia and TD were randomly assigned to either the active (N=35) or sham (N=29) group. Treatment was given 15 times, with each session lasting for 30 min, and an intensity of 2 mA. The anode was placed on the left dorsolateral prefrontal cortex and the cathode on the right supraorbital region. Primary outcome was measured by the changes in Abnormal Involuntary Movements Scale (AIMS) score. Secondary outcomes were measured using the Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS). Adverse effects of tDCS were assessed with an experimenter-administered open-ended questionnaire throughout the experiment. RESULTS: Of the 64 patients, 52 (81.25%) completed the study. Compared to the sham group, patients in the active group exhibited a significant reduction in both the total AIMS score and the facial-oral subscore (P<0.05). An improvement of at least 30% in total AIMS scores was observed in the active group (14 patients, 50%) compared to the sham group (2 patients, 8.3%) after treatment (P<0.01). There were no between-group differences in the PANSS and SANS total scores. However, there was a significant difference between the two groups in the occurrence of the reported adverse effect of tingling sensation (P<0.05). CONCLUSIONS: TDCS may be an effective and safe treatment for improving the facial-oral motor symptoms of TD in chronically hospitalized patients with schizophrenia. SIGNIFICANCE: This study provides a novel perspective for the clinical treatment of patients with TD.

Effects of transcranial magnetic stimulation on sleep structure and quality in children with autism.

Introduction: Sleep disorders are common in children with autism spectrum disorder (ASD). Transcranial magnetic stimulation (TMS) can influence the excitability of neuronal cells in stimulated areas, leading to improvements in sleep and other autistic symptoms. However, studies on clinical mechanisms of TMS in treating sleep disorders associated with ASD are limited. Therefore, we aimed to explore the effects of TMS on sleep structure and quality in children with ASD. Methods: Between January 2020 and December 2021, recruitment was advertised through child and adolescent outpatient clinics and online platforms by the Hangzhou Seventh People's Hospital and Lishui Second People's Hospital. Sixty children with ASD who met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were selected and randomly divided into the active TMS and sham TMS treatment groups. Thirty healthy children of the same age were recruited as controls. The active TMS group received bilateral low-frequency (0.5 Hz) TMS targeting the dorsolateral prefrontal cortex on both sides in children with ASD, whereas the sham TMS group received sham stimulation with the same stimulation time and location as the experimental group. Both groups were treated for 6 weeks, and the participants were assessed using the Sleep Disturbance Scale for Children (SDSC) before treatment, at 3 weeks, and at 6 weeks of intervention. Independent sample t-tests and difference t-tests were used for statistical analysis of the data. Results: No significant differences were observed in general demographic variables, such as age and sex, between the ASD and control groups (P>0.05). Independent sample t-test analysis showed that the total SDSC score, difficulty falling asleep, sleep maintenance, awakening disorders, sleep-wake transition disorders, excessive daytime sleepiness, and nocturnal hyperhidrosis scores were significantly higher in the ASD group than in the control group (P<0.05). Before treatment, no significant differences were observed in the factor or total SDSC scores between the sham TMS group and the active TMS group (P>0.05). After 15 and 30 treatment sessions, the total SDSC score, difficulty falling asleep, sleep maintenance, sleep-wake transition disorders, and excessive daytime sleepiness scores were significantly higher in the sham TMS group than in the active TMS group (P<0.05). The difference t-test analysis showed that after 30 treatment sessions, the reduction rates of the total SDSC score, difficulty falling asleep, sleep maintenance, awakening disorders, sleep-wake transition disorders, excessive daytime sleepiness, and nocturnal hyperhidrosis dimensions were significantly higher in the active TMS group than in the sham TMS group (P<0.05). Conclusion: Low-frequency TMS targeting the dorsolateral prefrontal cortex in children with ASD can effectively improve their sleep status, and significant improvement can be achieved after 6 weeks (30 sessions) of treatment.

Transcranial Direct Current Stimulation for Food Craving in Women Affected by Overweight and Obesity: A Randomized Controlled Trial.

INTRODUCTION: Craving is a multifactorial behavior caused by central circuit imbalance. The proposed treatments involve exercise and reduced food intake. However, the treatments frequently fail. This study aimed to investigate the effect of 10 consecutive sessions of anodal transcranial direct current stimulation over the right dorsolateral prefrontal cortex on food craving and eating consumption of women affected by overweight and obesity. METHODS: A randomized double-blind controlled trial with 50 volunteers was divided into two groups (active-tDCS: n = 25 and sham-tDCS: n = 25). There were a total of 10 consecutive tDCS sessions (2 mA, for 20 min) with an F4 anodal-F3 cathodal montage. We evaluated the effects on eating behavior (food craving, uncontrolled eating, emotional eating, and cognitive restriction), food consumption (calories and macronutrients), and anthropometric and body composition variables (weight, body mass index, waist circumference, and body fat percentage). RESULTS: There were no statistically significant results between groups at the baseline regarding sociodemographic and clinical characteristics. Also, there was no significant interaction between time versus group for any of the variables studied. Treatment with tDCS was well tolerated and there were no serious adverse effects. CONCLUSIONS: In women affected by overweight and obesity with food cravings, 10 sessions of F4 (anodal) and F3 (cathodal) tDCS did not produce changes in eating behavior, food consumption, and anthropometric and body composition.

The impact of transcranial direct current stimulation combined with interim testing on spatial route learning in patients with schizophrenia.

BACKGROUND: Cognitive deficits in patients with schizophrenia have drawn widespread attention. Transcranial direct current stimulation (tDCS) can modulate cognitive processes by altering neuronal excitability. Previous studies have found that interim testing can enhance spatial route learning and memory in patients with schizophrenia. However, there has been limited research on the combined effects of these two methods on spatial route learning in these patients. OBJECTIVE: To investigate whether the combination of tDCS and interim testing can effectively contribute to the maintenance of spatial route memory in patients with schizophrenia. The study involved conducting route learning using interim testing after anodal tDCS treatment on the left dorsolateral prefrontal cortex (L-DLPFC). METHODS: Ninety-two patients with schizophrenia were recruited and divided into groups receiving anodal, sham, or no stimulation. The anodal group received L-DLPFC tDCS treatment 10 times over 5 days (twice daily for 20 min). After treatment, spatial route learning was assessed in interim testing. Correct recall rates of landmark positions and proactive interference from prior learning were compared among the groups. RESULTS: Regardless of stimulation type, the interim testing group outperformed the relearning group. Additionally, recall scores were higher following anodal stimulation, indicating the efficacy of tDCS. CONCLUSIONS: Both tDCS and interim testing independently enhance the ability to learn new information in spatial route learning for patients with schizophrenia, indicating that tDCS of the left DLPFC significantly improves memory in these patients.

The neural structures of theory of mind are valence-sensitive: evidence from three tDCS studies.

Several cortical structures are involved in theory of mind (ToM), including the dorsolateral prefrontal cortex (dlPFC), the ventromedial prefrontal cortex (vmPFC), and the right temporo- parietal junction (rTPJ). We investigated the role of these regions in mind reading with respect to the valence of mental states. Sixty-five healthy adult participants were recruited and received transcranial direct current stimulation (tDCS) (1.5 mA, 20 min) with one week interval in three separate studies. The stimulation conditions were anodal tDCS over the dlPFC coupled with cathodal tDCS over the vmPFC, reversed stimulation conditions, and sham in the first study, and anodal tDCS over the vmPFC, or dlPFC, and sham stimulation, with an extracranial return electrode in the second and third study. During stimulation, participants underwent the reading mind from eyes/voice tests (RMET or RMVT) in each stimulation condition. Anodal left dlPFC/cathodal right vmPFC stimulation increased the accuracy of negative mental state attributions, anodal rTPJ decreased the accuracy of negative and neutral mental state attributions, and decreased the reaction time of positive mental state attributions. Our results imply that the neural correlates of ToM are valence-sensitive.

Expression of WNT Signaling Genes in the Dorsolateral Prefrontal Cortex in Schizophrenia.

Gene expression alterations in postmortem schizophrenia tissue are well-documented and are influenced by genetic, medication, and epigenetic factors. The Wingless/Integrated (WNT) signaling pathway, critical for cell growth and development, is involved in various cellular processes including neurodevelopment and synaptic plasticity. Despite its importance, WNT signaling remains understudied in schizophrenia, a disorder characterized by metabolic and bioenergetic defects in cortical regions. In this study, we examined the gene expression of 10 key WNT signaling pathway transcripts: IQGAP1, CTNNß1, GSK3ß, FOXO1, LRP6, MGEA5, TCF4, ßTRC, PPP1Cß, and DVL2 in the dorsolateral prefrontal cortex (DLPFC) using postmortem tissue from schizophrenia subjects (n = 20, 10 males, 10 females) compared to age, pH, and postmortem interval (PMI)-matched controls (n = 20, 10 males, 10 females). Employing the R-shiny application Kaleidoscope, we conducted in silico "lookup" studies from published transcriptomic datasets to examine cell- and region-level expression of these WNT genes. In addition, we investigated the impact of antipsychotics on the mRNA expression of the WNT genes of interest in rodent brain transcriptomic datasets. Our findings revealed no significant changes in region-level WNT transcript expression; however, analyses of previously published cell-level datasets indicated alterations in WNT transcript expression and antipsychotic-specific modulation of certain genes. These results suggest that WNT signaling transcripts may be variably expressed at the cellular level and influenced by antipsychotic treatment, providing novel insights into the role of WNT signaling in the pathophysiology of schizophrenia.

Transcranial direct current stimulation of the prefrontal and visual cortices diversely affects early and late perceptual learning.

BACKGROUND: Research has shown that visual perceptual learning (VPL) is related to modifying neural activity in higher level decision-making regions. However, the causal roles of the prefrontal and visual cortexes in VPL are still unclear. Here, we investigated how anodal transcranial direct current stimulation (tDCS) of the prefrontal and visual cortices modulates VPL in the early and later phases and the role of multiple brain regions. METHODS: Perceptual learning on the coherent motion direction identification task included early and later stages. After early training, participants needed to continuously train to reach a plateau; once the plateau was reached, participants entered a later stage. Sixty participants were randomly divided into five groups. Regardless of the training at the early and later stages, four groups received multitarget tDCS over the right dorsolateral prefrontal cortex (rDLPFC) and right middle temporal area (rMT), single-target tDCS over the rDLPFC, and single-target tDCS over the rMT or sham stimulation, and one group was stimulated at the ipsilateral brain region (i.e., left MT). RESULTS: Compared with sham stimulation, multitarget and two single-target tDCS over the rDLPFC or rMT improved posttest performance and accelerated learning during the early period. However, multitarget tDCS and two single-target tDCS led to equivalent benefits for VPL. Additionally, these beneficial effects were absent when anodal tDCS was applied to the ipsilateral brain region. For the later period, the above facilitating effects on VPL induced by multitarget or single-target tDCS disappeared. CONCLUSIONS: This study suggested the causal role of the prefrontal and visual cortices in visual motion perceptual learning by anodal tDCS but failed to find greater beneficial effects by simultaneously stimulating the prefrontal and visual cortices. Future research should investigate the functional associations between multiple brain regions to further promote VPL.

Developmental dynamics of the prefrontal cortical SST and PV interneuron networks: Insights from the monkey highlight human-specific features.

The primate prefrontal cortex (PFC) is a quintessential hub of cognitive functions. Amidst its intricate neural architecture, the interplay of distinct neuronal subtypes, notably parvalbumin (PV) and somatostatin (SST) interneurons (INs), emerge as a cornerstone in sculpting cortical circuitry and governing cognitive processes. While considerable strides have been made in elucidating the developmental trajectory of these neurons in rodent models, our understanding of their postmigration developmental dynamics in primates still needs to be studied. Disruptions to this developmental trajectory can compromise IN function, impairing signal gating and circuit modulation within cortical networks. This study examined the expression patterns of PV and SST, ion transporter KCC2, and ion channel subtypes Kv3.1b, and Nav1.1 - associated with morphophysiological stages of development in the postnatal marmoset monkey in different frontal cortical regions (granular areas 8aD, 8aV, 9, 46; agranular areas 11, 47L). Our results demonstrate that the maturation of PV+ INs extends into adolescence, characterized by discrete epochs associated with specific expression dynamics of ion channel subtypes. Interestingly, we observed a postnatal decrease in SST interneurons, contrasting with studies in rodents. This endeavor broadens our comprehension of primate cortical development and furnishes invaluable insights into the etiology and pathophysiology of neurodevelopmental disorders characterized by perturbations in PV and SST IN function.

Prefrontal metabolite alterations in individuals with posttraumatic stress disorder: a 7T magnetic resonance spectroscopy study.

Background: Evidence from animal and human studies suggests glutamatergic dysfunction in posttraumatic stress disorder (PTSD). The purpose of this study was to investigate glutamate abnormalities in the dorsolateral prefrontal cortex (DLFPC) of individuals with PTSD using 7T MRS, which has better spectral resolution and signal-to-noise ratio than lower field strengths, thus allowing for better spectral quality and higher sensitivity. We hypothesized that individuals with PTSD would have lower glutamate levels compared to trauma-exposed individuals without PTSD and individuals without trauma exposure. Additionally, we explored potential alterations in other neurometabolites and the relationship between glutamate and psychiatric symptoms. Methods: Individuals with PTSD (n=27), trauma-exposed individuals without PTSD (n=27), and individuals without trauma exposure (n=26) underwent 7T MRS to measure glutamate and other neurometabolites in the left DLPFC. The severities of PTSD, depression, anxiety, and dissociation symptoms were assessed. Results: We found that glutamate was lower in the PTSD and trauma-exposed groups compared to the group without trauma exposure. Furthermore, N-acetylaspartate (NAA) was lower and lactate was higher in the PTSD group compared to the group without trauma exposure. Glutamate was negatively correlated with depression symptom severity in the PTSD group. Glutamate was not correlated with PTSD symptom severity. Conclusion: In this first 7T MRS study of PTSD, we observed altered concentrations of glutamate, NAA, and lactate. Our findings provide evidence for multiple possible pathological processes in individuals with PTSD. High-field MRS offers insight into the neurometabolic alterations associated with PTSD and is a powerful tool to probe trauma- and stress-related neurotransmission and metabolism in vivo.

Different activation in dorsolateral prefrontal cortex between anxious depression and non-anxious depression during an autobiographical memory task: A fNIRS study.

OBJECTIVE: Using functional near-infrared spectroscopy (fNIRS) previous studies have found that activation differences in the dorsolateral prefrontal cortex (DLPFC) during an autobiographical memory task (AMT) under the condition of different emotional valences may be neurophysiological markers of depression and different depression subtypes. Additionally, compared with non-anxious depression, anxious depression presents abnormal hemodynamic activation in the DLPFC. This study aimed to use fNIRS to investigate hemodynamic activation in the DLPFC of depression patients with and without anxiety during AMT triggered by different emotional valence stimuli. METHODS: We recruited 194 patients with depression (91 with non-anxious depression, 103 with anxious depression) and 110 healthy controls from Chinese college students. A 53-channel fNIRS was used to detect cerebral hemodynamic differences in the three groups during AMT. RESULTS: The results showed that: (1) the activation of oxy-Hb in the left DLPFC was significantly higher under positive emotional valence than under negative emotional valence for healthy controls and patients with non-anxious depression, while there was no significant difference between positive and negative emotional valence observed in response to anxious depression; and (2) Oxy-Hb activation under negative emotional valence was significantly higher in the anxious depression group than in the non-anxious depression group. CONCLUSIONS: This study revealed that the hemodynamic hyperactivation of negative emotional valence in the left DLPFC may be due to the neurophysiological differences between anxious and non-anxious patients with depression.

Cortical functional mechanisms in emotional cognitive tasks in first-episode, drug-naïve with major depressive disorder: A fNIRS study.

BACKGROUND: Previous research has revealed that patients with major depressive disorder (MDD) have negative biases in various aspects of information processing, and these biases are mainly manifested in recognizing facial expressions. However, the link between this emotional cognitive inhibition and neural activation mechanisms in cortical brain regions remains poorly understood. Therefore, this study employed functional near-infrared spectroscopy (fNIRS) to explore the potential impaired regions and neural mechanisms associated with facial emotion cognition in MDD patients. METHODS: 37 MDD patients and 34 healthy controls (HC) were recruited to participate in three sets of cognitive tasks for emotion recognition, and the cortical activation in the brain was synchronously recorded using multi-channel fNIRS. RESULTS: During tasks requiring the motions identification of sad versus happy emotional states, MDD patients exhibit altered activation in both the left frontopolar cortex (FPC) and the right dorsolateral prefrontal cortex (DLPFC). Notably, the FPC demonstrates a higher level of internal coherence and broader correlation with other cortical areas. Moreover, MDD patients showed lower accuracy in distinguishing emotional cues associated with sadness versus those associated with neutral and happy emotions. LIMITATIONS: The study had a relatively small sample size, and it specifically examined only three prevalent facial expressions. CONCLUSION: Facial expression recognition in MDD patients is characterized by negative cognitive interpretation of expressions, which are associated with various cortical altered activations. Neuroimaging further suggests that the cognitive inhibition of emotion signal recognition in everyday interpersonal interactions in MDD patients may primarily be influenced by activation in the left FPC.

Regional brain activity and neural network changes in cognitive-motor dual-task interference: A functional near-infrared spectroscopy study.

Previous neuroimaging studies have reported dual-task interference (DTi) and deterioration of task performance in a cognitive-motor dual task (DT) compared to that in a single task (ST). Greater frontoparietal activity is a neural signature of DTi; nonetheless, the underlying mechanism of cortical network in DTi still remains unclear. This study aimed to investigate the regional brain activity and neural network changes during DTi induced by highly demanding cognitive-motor DT. Thirty-four right-handed healthy young adults performed the spiral-drawing task. They underwent a paced auditory serial addition test (PASAT) simultaneously or independently while their cortical activity was measured using functional near-infrared spectroscopy. Motor performance was determined using the balanced integration score (BIS), a balanced index of drawing speed and precision. The cognitive task of the PASAT was administered with two difficulty levels defined by 1 s (PASAT-1 s) and 2 s (PASAT-2 s) intervals, allowing for the serial addition of numbers. Cognitive performance was determined using the percentage of correct responses. These motor and cognitive performances were significantly reduced during DT, which combined a drawing and a cognitive task at either difficulty level, compared to those in the corresponding ST conditions. The DT conditions were also characterized by significantly increased activity in the right dorsolateral prefrontal cortex (DLPFC) compared to that in the ST conditions. Multivariate Granger causality (GC) analysis of cortical activity in the selected frontoparietal regions of interest further revealed selective top-down causal connectivity from the right DLPFC to the right inferior parietal cortex during DTs. Furthermore, changes in the frontoparietal GC connectivity strength between the PASAT-2 s DT and ST conditions significantly correlated negatively with changes in the percentage of correct responses. Therefore, DTi can occur even in cognitively proficient young adults, and the right DLPFC and frontoparietal network being crucial neural mechanisms underlying DTi. These findings provide new insights into DTi and its underlying neural mechanisms and have implications for the clinical utility of cognitive-motor DTs applied to clinical populations with cognitive decline, such as those with psychiatric and brain disorders.

Validation of the number of pulses required for TMS-EEG in the prefrontal cortex considering test feasibility.

BACKGROUND: Transcranial magnetic stimulation (TMS) combined with electroencephalography (EEG), TMS-EEG, is a useful neuroscientific tool for the assessment of neurophysiology in the human cerebral cortex. Theoretically, TMS-EEG data is expected to have a better data quality as the number of stimulation pulses increases. However, since TMS-EEG testing is a modality that is examined on human subjects, the burden on the subject and tolerability of the test must also be carefully considered. METHOD: In this study, we aimed to determine the number of stimulation pulses that satisfy the reliability and validity of data quality in single-pulse TMS (spTMS) for the dorsolateral prefrontal cortex (DLPFC). TMS-EEG data for (1) 40-pulse, (2) 80-pulse, (3) 160-pulse, and (4) 240-pulse conditions were extracted from spTMS experimental data for the left DLPFC of 20 healthy subjects, and the similarities between TMS-evoked potentials (TEP) and oscillations across the conditions were evaluated. RESULTS: As a result, (2) 80-pulse and (3) 160-pulse conditions showed highly equivalent to the benchmark condition of (4) 240-pulse condition. However, (1) 40-pulse condition showed only weak to moderate equivalence to the (4) 240-pulse condition. Thus, in the DLPFC TMS-EEG experiment, 80 pulses of stimulations was found to be a reasonable enough number of pulses to extract reliable TEPs, compared to 160 or 240 pulses. CONCLUSIONS: This is the first substantial study to examine the appropriate number of stimulus pulses that are reasonable and feasible for TMS-EEG testing of the DLPFC.

Transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex reduced attentional bias toward natural emotional sounds.

Previous research has indicated that the left dorsolateral prefrontal cortex (DLPFC) exerts an influence on attentional bias toward visual emotional information. However, it remains unclear whether the left DLPFC also play an important role in attentional bias toward natural emotional sounds. The current research employed the emotional spatial cueing paradigm, incorporating natural emotional sounds of considerable ecological validity as auditory cues. Additionally, high-definition transcranial direct current stimulation (HD-tDCS) was utilized to examine the impact of left dorsolateral prefrontal cortex (DLPFC) on attentional bias and its subcomponents, namely attentional engagement and attentional disengagement. The results showed that (1) compared to sham condition, anodal HD-tDCS over the left DLPFC reduced the attentional bias toward positive and negative sounds; (2) anodal HD-tDCS over the left DLPFC reduced the attentional engagement toward positive and negative sounds, whereas it did not affect attentional disengagement away from natural emotional sounds. Taken together, the present study has shown that left DLPFC, which was closely related with the top-down attention regulatory function, plays an important role in auditory emotional attentional bias.