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Objective: Transcranial direct current stimulation (tDCS) has mixed effects for major depressive disorder (MDD) symptoms, partially owing to large inter-experimental variability in tDCS protocols and their correlated induced electric fields (E-fields). We investigated whether the E-field strength of distinct tDCS parameters was associated with antidepressant effect. Methods: A meta-analysis was performed with placebo-controlled clinical trials of tDCS enrolling MDD patients. PubMed, EMBASE, and Web of Science were searched from inception to March 10, 2023. Effect sizes of tDCS protocols were correlated with E-field simulations (SimNIBS) of brain regions of interest (bilateral dorsolateral prefrontal cortex [DLPFC] and bilateral subgenual anterior cingulate cortex [sgACC]). Moderators of tDCS responses were also investigated. Results: A total of 20 studies were included (21 datasets, 1,008 patients), using 11 distinct tDCS protocols. Results revealed a moderate effect for MDD (g = 0.41, 95%CI 0.18-0.64), while cathode position and treatment strategy were found to be moderators of response. A negative association between effect size and tDCS-induced E-field magnitude was seen, with stronger E-fields in the right frontal and medial parts of the DLPFC (targeted by the cathode) leading to smaller effects. No association was found for the left DLPFC and the bilateral sgACC. An optimized tDCS protocol is proposed. Conclusions: Our results highlight the need for a standardized tDCS protocol in MDD clinical trials. Registration number: PROSPERO CRD42022296246.
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ABSTRACT Primary progressive aphasia comprises a group of neurodegenerative diseases characterized by progressive speech and language dysfunction. Neuroimaging (structural and functional), biomarkers, and neuropsychological assessments allow for early diagnosis. However, there is no pharmacological treatment for the disease. Speech and language therapy is the main rehabilitation strategy. In this case report, we describe a female patient diagnosed with nonfluent primary progressive aphasia who underwent sessions of high-frequency transcranial magnetic stimulation in the left dorsolateral prefrontal cortex and showed improvement in depression scores, naming tasks in oral and written speech, and comprehension tasks in oral and written discourse.
RESUMO As afasias progressivas primárias (APP) representam um grupo de doenças neurodegenerativas caracterizadas por disfunção progressiva da fala e da linguagem. A neuroimagem (estrutural e funcional), os biomarcadores e as avaliações neuropsicológicas permitem o diagnóstico precoce. No entanto, não há tratamento farmacológico para a doença. A terapia fonoaudiológica é a principal estratégia de reabilitação. Neste relato de caso, descrevemos uma paciente com diagnóstico de APP não fluente que foi submetida a sessões de estimulação magnética transcraniana de alta frequência no córtex pré-frontal dorsolateral esquerdo e apresentou melhora nos escores de depressão, nas tarefas de nomeação da fala oral e escrita e nas tarefas de compreensão da fala oral e escrita.
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Objective:To investigate the effect of a single-trial transcranial direct current stimulation(tDCS) of the dorsolateral prefrontal cortex (DLPFC) on fairness-related decision-making behavior.Methods:From September 2018 to February 2019, a total of 60 healthy participants between the ages of 18 and 45 were enrolled.Then, the participants were randomly divided into 3 groups with 20 in each group to receive left anode stimulation/right cathode stimulation (left anode /right cathode group), left cathode/right anode stimulation (left cathode /right anode group) or bilateral control electrodes (sham stimulation group) on the bilateral dorsolateral prefrontal cortices (DLPFC), respectively.After tDCS, the participants immediately completed the ultimatum game (UG) task as responders and a fairness questionnaire in turn.SPSS 22.0 statistical software was used to analyze the data with repeated measurement ANOVA and nonparametric test.Results:In the UG task, there was no significant difference in the acceptance rate among the three groups of participants as responders (all P>0.05). When analyzing the acceptance rate facing different proposers (" computer" and " human" ) under different fairness levels in the three stimulus types through the paired samples Wilcoxon test, it was found that the acceptance rate of the sham stimulation group to the extremely unfair proposals proposed by the human opponent was lower than that proposed by the computer(0.28 (0, 0.67), 0.44 (0.33, 0.89), Z=-2.14, P=0.032), while there was no difference in acceptance rates (both P>0.05) in the face of fair or unfair proposals proposed by computer and human opponents.The acceptance rate of the left cathode /right anode group to the unfair(0.90 (0.50, 1.00), 1.00 (0.70, 1.00), Z=-1.90, P=0.046)or extremely unfair(0.44 (0, 1.00), 0.89 (0.50, 1.00), Z=-2.73, P=0.006) proposals proposed by human opponents was significantly lower than the proposals proposed by computer opponent, and there was no differences in acceptance rate when facing fair proposals proposed by computer and human opponents ( P> 0.05). There were no significant differences in acceptance rates in the left anode /right cathode group when faced with fair, unfair, and extremely unfair schemes proposed by computer and human opponents (all P>0.05). For fairness questionnaire scores, a repeated measurements ANOVA showed that the interaction effect between group and proposer types was not significant ( F(2, 54)=2.037, P=0.140), and the group main effect was not significant ( F(1, 54)=0.165, P=0.848), but the proposer type main effect was significant ( F(1, 54)=6.363, P=0.015), indicating that the fairness questionnaire score in the face of the human opponents was lower than when facing the computer opponents( P<0.05). Conclusion:Although a single-trial tDCS on bilateral DLPFC has no significant effect on the overall acceptance rate of fairness-related decision-making, it affects the decision-making of unfair distribution scheme proposed by human or computer.
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Objective:To investigate the effects of single intermittent theta-burst stimulation on functional connectivity in patients with mild cognitive impairment(MCI).Methods:From July to November 2020, forty MCI patients were selected and randomly divided into iTBS true stimulation group and iTBS sham-stimulation group, with 20 patients in each group.iTBS targeted the left dorsolateral prefrontal cortex (DLPFC). Montreal cognitive assessment (MoCA), mini-mental state examination (MMSE), activity of daily living scale(ADL), Hamilton depression scale (HAMD) and Hamilton anxiety scale (HAMA) were evaluated at baseline.The resting state electroencephalography (rsEEG) was collected for 5 minutes before and after iTBS in the two groups.The phase lag index(PLI) of EEG functional connectivity was calculated, and the functional connectivity matrix diagram was drawn.SPSS 26.0 software was used for statistical analysis.Data were statistically analyzed by χ2 test, Wilcoxon rank sum test and independent sample t-test. Results:There were no significant differences in scores of MoCA, ADL, HAMD and HAMA between the two groups(all P>0.05). In the iTBS true stimulation group, compared with that before iTBS treatment(0.140(0.133, 0.144)), the PLI of β band increased significantly after iTBS treatment(0.146(0.136, 0.167))( P<0.05). The region of increased PLI was mainly concentrated in the central region(C3/C4-T7/T8). Compared with that before iTBS treatment(0.251(0.232, 0.299)), the PLI of α band increased after iTBS treatment(0.286(0.241, 0.359)), but the difference was not statistically significant( P>0.05). Conclusion:Single iTBS treatment can significantly increase the EEG functional connectivity in patients with MCI, indicating that iTBS targeting the left DLPFC can effectively regulate the EEG functional connectivity in patients with MCI, which may reveal the mechanism of iTBS in improving cognitive function in patients with MCI.
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Objective:To explore the effect of repeated high-frequency transcranial magnetic stimulation over the left dorsolateral prefrontal cortex (DLPFC) on the severity and symptoms of Internet addiction.Methods:Fifty college students with different degrees of Internet addiction were randomly divided into a treatment group and a control group, each of 25. In addition to psycho-behavioral therapy, the treatment group was given 10Hz rTMS over the left DLPFC for 40 days, while the control group was given sham stimulation. Before the experiment and after 4 and 8 weeks of treatment, both groups were evaluated using the Internet Addiction Diagnostic Scale (IAT), Barratt Impulsiveness Scale (BIS-11) and a visual analogue scale (VAS).Results:After 4 weeks the average total BIS-11 score, attention factor score and VAS score of the treatment group were significantly better than the control group′s averages and better than before the treatment. After 8 weeks of treatment, the average IAT scores, BIS-11 scores on each item and VAS scores of the treatment group had decreased significantly more and were still significantly better than the control group′s averages.Conclusion:High frequency rTMS can safely and effectively relieve the symptoms of Internet addiction, at least among college students.
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Objective:To observe any effect of transcranial direct current stimulation (tDCS) on the speed and accuracy of picture naming and on the phonological fluency of aphasic stroke survivors.Methods:Twenty-four stroke survivors with aphasia were randomly divided into an observation group and a control group, each of 12. In addition to language training and picture naming training, the observation group received 20 minutes of tDCS over the left dorsolateral prefrontal cortex (DLPFC) daily, 5 days a week for 2 weeks. The control group was given sham stimulation. Before and after the 2 weeks of treatment, both groups were tested for picture naming and phonological fluency.Results:Significant improvement in the number of accurately pronounced high-frequency words and in reaction time was observed in both groups, but the observation group′s average reaction time for high-frequency words was significantly shorter than the control group′s average. The observation group′s average reaction time for low-frequency words had also improved significantly. After the 2 weeks of treatment, the phonological fluency of the observation group was significantly better than before the treatment and better than that of the control group.Conclusions:tDCS applied over the left DLPFC of stroke survivors with aphasia can promote lexical retrieval and strengthen their executive and control functioning.
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Abstract Objectives Fibromyalgia Syndrome (FMS), is a chronic pain disorder with poorly understood pathophysiology. In recent years, repetitive transcranial magnetic stimulation (rTMS) has been recommended for pain relief in various chronic pain disorders. The objective of the present research was to study the effect of low frequency rTMS over the right dorsolateral prefrontal cortex (DLPFC) on pain status in FMS. Methods Ninety diagnosed cases of FMS were randomized into Sham-rTMS and Real-rTMS groups. Real rTMS (1 Hz/1200 pulses/8 trains/90% resting motor threshold) was delivered over the right DLPFC for 5 consecutive days/week for 4 weeks. Pain was assessed by subjective and objective methods along with oxidative stress markers. Patients were followed up for 6 months (post-rTMS;15 days, 3 months and 6 months). Results In Real-rTMS group, average pain ratings and associated symptoms showed significant improvement post rTMS. The beneficial effects of rTMS lasted up to 6 months in the follow-up phase. In Sham-rTMS group, no significant change in pain ratings was observed. Conclusion Right DLPFC rTMS can significantly reduce pain and associated symptoms of FMS probably through targeting spinal pain circuits and top-down pain modulation . Trial registration: Ref No: CTRI/2013/12/004228.(AU)
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Humans , Fibromyalgia/therapy , Chronic Pain , Prefrontal Cortex , Oxidative Stress , Diffuse Noxious Inhibitory ControlABSTRACT
Transcranial direct current stimulation (tDCS) is a promising method for altering cortical excitability with clinical implications. It has been increasingly used in neurodevelopmental disorders, especially attention-deficit hyperactivity disorder (ADHD), but its efficacy (based on effect size calculations), safety, and stimulation parameters have not been systematically examined. In this systematic review, we aimed to (1) explore the effectiveness of tDCS on the clinical symptoms and neuropsychological deficits of ADHD patients, (2) evaluate the safety of tDCS application, especially in children with ADHD, (3) model the electrical field intensity in the target regions based on the commonly-applied and effective versus less-effective protocols, and (4) discuss and propose advanced tDCS parameters. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach, a literature search identified 14 empirical experiments investigating tDCS effects in ADHD. Partial improving effects of tDCS on cognitive deficits (response inhibition, working memory, attention, and cognitive flexibility) or clinical symptoms (e.g., impulsivity and inattention) are reported in 10 studies. No serious adverse effects are reported in 747 sessions of tDCS. The left and right dorsolateral prefrontal cortex are the regions most often targeted, and anodal tDCS the protocol most often applied. An intensity of 2 mA induced stronger electrical fields than 1 mA in adults with ADHD and was associated with significant behavioral changes. In ADHD children, however, the electrical field induced by 1 mA, which is likely larger than the electrical field induced by 1 mA in adults due to the smaller head size of children, was sufficient to result in significant behavioral change. Overall, tDCS seems to be a promising method for improving ADHD deficits. However, the clinical utility of tDCS in ADHD cannot yet be concluded and requires further systematic investigation in larger sample sizes. Cortical regions involved in ADHD pathophysiology, stimulation parameters (e.g. intensity, duration, polarity, and electrode size), and types of symptom/deficit are potential determinants of tDCS efficacy in ADHD. Developmental aspects of tDCS in childhood ADHD should be considered as well.
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Transcranial direct current stimulation (tDCS) is a promising method for altering cortical excitability with clinical implications. It has been increasingly used in neurodevelopmental disorders, especially attention-deficit hyperactivity disorder (ADHD), but its efficacy (based on effect size calculations), safety, and stimulation parameters have not been systematically examined. In this systematic review, we aimed to (1) explore the effectiveness of tDCS on the clinical symptoms and neuropsychological deficits of ADHD patients, (2) evaluate the safety of tDCS application, especially in children with ADHD, (3) model the electrical field intensity in the target regions based on the commonly-applied and effective versus less-effective protocols, and (4) discuss and propose advanced tDCS parameters. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach, a literature search identified 14 empirical experiments investigating tDCS effects in ADHD. Partial improving effects of tDCS on cognitive deficits (response inhibition, working memory, attention, and cognitive flexibility) or clinical symptoms (e.g., impulsivity and inattention) are reported in 10 studies. No serious adverse effects are reported in 747 sessions of tDCS. The left and right dorsolateral prefrontal cortex are the regions most often targeted, and anodal tDCS the protocol most often applied. An intensity of 2 mA induced stronger electrical fields than 1 mA in adults with ADHD and was associated with significant behavioral changes. In ADHD children, however, the electrical field induced by 1 mA, which is likely larger than the electrical field induced by 1 mA in adults due to the smaller head size of children, was sufficient to result in significant behavioral change. Overall, tDCS seems to be a promising method for improving ADHD deficits. However, the clinical utility of tDCS in ADHD cannot yet be concluded and requires further systematic investigation in larger sample sizes. Cortical regions involved in ADHD pathophysiology, stimulation parameters (e.g. intensity, duration, polarity, and electrode size), and types of symptom/deficit are potential determinants of tDCS efficacy in ADHD. Developmental aspects of tDCS in childhood ADHD should be considered as well.
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Transcranial direct current stimulation (tDCS) is a novel brain stimulation technique which has kindled hope in alleviating motor, language as well as cognitive deficits in neuronal injury. Current case report describes application of tDCS in two phases using two different protocols in a patient with hypoxic injury. In the first phase anodal stimulation of dorsolateral prefrontal cortex improved the language fluency. Subsequently, after 6 months second phase application of anodal stimulation over posterior parietal region targeted arithmetic and working memory deficits. Individualising the treatment protocols of brain stimulation, based on the lesion and the functional deficits, for neuro-rehabilitation is emphasised.
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Humans , Brain , Clinical Protocols , Cognition Disorders , Dyscalculia , Hope , Hypoxia-Ischemia, Brain , Memory, Short-Term , Neurons , Parietal Lobe , Prefrontal Cortex , Rehabilitation , Transcranial Direct Current StimulationABSTRACT
Objective To investigate whether modulating the activation of dorsolateral prefrontal cortex(DLPFC) by transcranial direct current stimulation(tDCS) can influence emotional perception. Meth-ods Seventy-eight undergraduates were randomly divided into four groups by simple random sampling meth-od. TDCS (1. 5 mA) noninvasive technique was used to test group 1 (n=23) for 3 minutes to intervene in DLPFC,group 2 (n=17) for 15 minutes to intervene in DLPFC,group 3 (n=20) for 3 minutes to intervene in primary visual cortex,and group 4 (n=18) for non-emotional picture test. The data were analyzed with re-peated measurement variance analysis. Results (1) The interaction between short-term(3 min) stimula-tion of tDCS and facial expression was statistically significant (F(1,22)=7. 448,P=0. 012). There was signifi- cant difference in positive face perception (before:70. 58%,period:74. 75%,P=0. 036) and no significant difference in negative face perception (before:70. 58%,period:70. 73%,P=0. 569). (2) There was no sig-nificant difference in the correlation between prolonged tDCS stimulation(15 min) and face expression recog-nition ( F (1,16)= 1. 621, P=0. 221). (3) The primary visual cortex was not affected by anodal tDCS (F(1,19)<1,P>0. 05). (4) There was no significant difference in the interaction between tDCS and facial ex-pression (F(1,17)=2. 566,P=0. 128) when visual stimulus was changed to non-expressive faces. Conclu-sions By applying tDCS technique,the present findings suggest that modulating DLPFC can influence emo-tional face perception,and support the valence-specific lateralization of emotional perception.
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The neuroimaging has been applied in the study of pathophysiology in major depressive disorder (MDD). In this review article, several kinds of methodologies of neuroimaging would be discussed to summarize the promising biomarkers in MDD. For the magnetic resonance imaging (MRI) and magnetoencephalography field, the literature review showed the potentially promising roles of frontal lobes, such as anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC). In addition, the limbic regions, such as hippocampus and amygdala, might be the potentially promising biomarkers for MDD. The structures and functions of ACC, DLPFC, OFC, amygdala and hippocampus might be confirmed as the biomarkers for the prediction of antidepressant treatment responses and for the pathophysiology of MDD. The functions of cognitive control and emotion regulation of these regions might be crucial for the establishment of biomarkers. The near-infrared spectroscopy studies demonstrated that blood flow in the frontal lobe, such as the DLPFC and OFC, might be the biomarkers for the field of near-infrared spectroscopy. The electroencephalography also supported the promising role of frontal regions, such as the ACC, DLPFC and OFC in the biomarker exploration, especially for the sleep electroencephalogram to detect biomarkers in MDD. The positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in MDD demonstrated the promising biomarkers for the frontal and limbic regions, such as ACC, DLPFC and amygdala. However, additional findings in brainstem and midbrain were also found in PET and SPECT. The promising neuroimaging biomarkers of MDD seemed focused in the fronto-limbic regions.
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Amygdala , Biomarkers , Brain Stem , Depression , Depressive Disorder, Major , Electroencephalography , Frontal Lobe , Gyrus Cinguli , Hippocampus , Magnetic Resonance Imaging , Magnetoencephalography , Mesencephalon , Neuroimaging , Positron-Emission Tomography , Prefrontal Cortex , Spectroscopy, Near-Infrared , Tomography, Emission-Computed , Tomography, Emission-Computed, Single-PhotonABSTRACT
At present, a considerable proportion of patients with obsessive-compulsive disorder (OCD) cannot be effectively relieved by standard drug and psychotherapy, so researchers have turned their attention to new directions of physiotherapy. Repetitive transcranial magnetic stimulation (rTMS), as an adjuvant therapy for refractory OCD, is a non-invasive nerve stimulation technique. Many studies have shown that rTMS is effective in the treatment of OCD. However, there were also disputes in the selection of stimulation targets, parameter settings and so on. This article systematically combs the setting and application of standard rTMS in the treatment of OCD, and comprehensive therapeutic effect of rTMS, and then discusses the deficiency of treatment so far, in order to put forward the future development direction and promote clinical treatment progress.
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An important and unresolved question is how human brain regions process information and interact with each other in intertemporal choice related to gains and losses. Using psychophysiological interaction and dynamic causal modeling analyses, we investigated the functional interactions between regions involved in the decision-making process while participants performed temporal discounting tasks in both the gains and losses domains. We found two distinct intrinsic valuation systems underlying temporal discounting in the gains and losses domains: gains were specifically evaluated in the medial regions, including the medial prefrontal and orbitofrontal cortices, and losses were evaluated in the lateral dorsolateral prefrontal cortex. In addition, immediate reward or punishment was found to modulate the functional interactions between the dorsolateral prefrontal cortex and distinct regions in both the gains and losses domains: in the gains domain, the mesolimbic regions; in the losses domain, the medial prefrontal cortex, anterior cingulate cortex, and insula. These findings suggest that intertemporal choice of gains and losses might involve distinct valuation systems, and more importantly, separate neural interactions may implement the intertemporal choices of gains and losses. These findings may provide a new biological perspective for understanding the neural mechanisms underlying intertemporal choice of gains and losses.
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Adult , Female , Humans , Male , Young Adult , Brain , Diagnostic Imaging , Physiology , Brain Mapping , Delay Discounting , Physiology , Magnetic Resonance Imaging , Neural Pathways , Diagnostic Imaging , Physiology , Neuropsychological Tests , Psychophysics , RewardABSTRACT
The ZNF804A variant rs1344706 has consistently been associated with schizophrenia and plays a role in hippocampal-prefrontal functional connectivity during working memory. Whether the effect exists in the resting state and in patients with schizophrenia remains unclear. In this study, we investigated the ZNF804A polymorphism at rs1344706 in 92 schizophrenic patients and 99 healthy controls of Han Chinese descent, and used resting-state functional magnetic resonance imaging to explore the functional connectivity in the participants. We found a significant main effect of genotype on the resting-state functional connectivity (RSFC) between the hippocampus and the dorsolateral prefrontal cortex (DLPFC) in both schizophrenic patients and healthy controls. The homozygous ZNF804A rs1344706 genotype (AA) conferred a high risk of schizophrenia, and also exhibited significantly decreased resting functional coupling between the left hippocampus and right DLPFC (F(2,165) = 13.43, P < 0.001). The RSFC strength was also correlated with cognitive performance and the severity of psychosis in schizophrenia. The current findings identified the neural impact of the ZNF804A rs1344706 on hippocampal-prefrontal RSFC associated with schizophrenia.
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Adult , Female , Humans , Male , Young Adult , Analysis of Variance , Functional Laterality , Genetics , Genotype , Hippocampus , Diagnostic Imaging , Image Processing, Computer-Assisted , Kruppel-Like Transcription Factors , Genetics , Magnetic Resonance Imaging , Neural Pathways , Diagnostic Imaging , Neuropsychological Tests , Oxygen , Blood , Polymorphism, Single Nucleotide , Genetics , Prefrontal Cortex , Diagnostic Imaging , Psychiatric Status Rating Scales , Schizophrenia , Diagnostic Imaging , Genetics , Severity of Illness IndexABSTRACT
The dorsolateral prefrontal cortex (DLPFC) is considered to play a crucial role in many high-level functions, such as cognitive control and emotional regulation. Many studies have reported that the DLPFC can be activated during the processing of emotional information in tasks requiring working memory. However, it is still not clear whether modulating the activity of the DLPFC influences emotional perception in a detection task. In the present study, using transcranial direct-current stimulation (tDCS), we investigated (1) whether modulating the right DLPFC influences emotional face processing in a detection task, and (2) whether the DLPFC plays equal roles in processing positive and negative emotional faces. The results showed that anodal tDCS over the right DLPFC specifically facilitated the perception of positive faces, but did not influence the processing of negative faces. In addition, anodal tDCS over the right primary visual cortex enhanced performance in the detection task regardless of emotional valence. Our findings suggest, for the first time, that modulating the right DLPFC influences emotional face perception, especially faces showing positive emotion.
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Adult , Female , Humans , Male , Young Adult , Emotions , Facial Recognition , Physiology , Neuropsychological Tests , Prefrontal Cortex , Physiology , Social Perception , Transcranial Direct Current StimulationABSTRACT
Objective To review psychopathic individuals' moral judgments and the underlying neural mechanisms in order to provide cognitive basis and the corresponding intervention for their socially deviant behavior.Methods Literatures were searched in Academic Search Premier,Science Direct,Highwire,PubMed and Wanfang database by July 2015.Index strategy:AB [psychopathy OR psychopathic] AND AB [moral judgments OR moral reasoning].Forty-seven articles including six in Chinese were chosen based on their abstracts and key words.Results 33 papers were adopted finally including 2 in Chinese.Most of the papers involved representative empirical studies within five years.Conclusion Compared with non-psychopathic individuals,psychopathic individuals are inclined to consider moral transgressions as more acceptable and are more inclined to make utilitarian moral judgments.Their impairment in moral judgments is associated with dysfunction in specific brain regions such as amygdale,dorsolateral prefrontal cortex,and ventromedial prefrontal cortex,and dysfunction in the basic brain system.Psychopathic individuals' moral judgment impairment needs to be examined within the frame of affect and their moral reasoning processes should be investigated in the future.
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OBJECTIVE: Genetic imaging is used to investigate the mechanism by which genetic variants influence brain structure. In a previous study, a structural change of the dorsolateral prefrontal cortex was associated with symptom modulation in post-traumatic stress disorder patients. This study examined the effect of a polymorphism in the gene encoding brain-derived neurotrophic factor (BDNF) on regional gray matter (GM) volumes and the correlations between the dorsolateral prefrontal GM volume and the stress level in healthy volunteers. METHODS: Sixty-one volunteers underwent genotyping for the BDNF Val66Met single nucleotide polymorphism (SNP) and completed the Stress Response Inventory (SRI). Magnetic resonance images were also acquired, and the effect of each subject's BDNF genotype and SRI subscore on his or her dorsolateral prefrontal GM volume was evaluated. RESULTS: The Val/Val homozygotes had significantly larger GM volumes in the prefrontal cortex and the precuneus, the uncus, and the superior temporal and occipital cortices than Met carriers. The Met homozygotes demonstrated a higher stress response in depression domain than Val/Val and Val/Met groups. A negative correlation between the middle frontal cortex GM volume and the SRI depression subscore was found. CONCLUSION: These findings indicate an interaction between genes and brain structure, and they suggest that differences in dorsolateral prefrontal GM volume related to the BDNF Val66Met SNP are associated with resilience to stressful life events, particularly in the dimension of emotion.
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Humans , Brain , Brain-Derived Neurotrophic Factor , Depression , Genotype , Homozygote , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , Polymorphism, Genetic , Polymorphism, Single Nucleotide , Prefrontal Cortex , Stress Disorders, Post-TraumaticABSTRACT
The aim of the present study was to determine whether specific subgroups of schizophrenic patients, grouped according to electrodermal characteristics, show differences in the N-acetylaspartate/creatine plus choline (NAA / (Cr + Cho)) ratios in the frontal, cingulate and perirolandic cortices. Skin conductance levels (SCL) and skin conductance responses to auditory stimulation were measured in 38 patients with schizophrenia and in the same number of matched healthy volunteers (control). All subjects were submitted to multivoxel proton magnetic resonance spectroscopic imaging. When compared to the control group, patients presented significantly lower NAA / (Cr + Cho) ratios in the right dorsolateral prefrontal cortex (schizophrenia = 0.95 ± 0.03; control = 1.12 ± 0.04) and in the right (schizophrenia = 0.88 ± 0.02; control = 0.94 ± 0.03) and left (schizophrenia = 0.84 ± 0.03; control = 0.94 ± 0.03) cingulates. These ratios did not differ between electrodermally responsive and non-responsive patients. When patients were divided into two groups: lower SCL (less than the mean SCL of the control group minus two standard deviations) and normal SCL (similar to the control group), the subgroup with a lower level of SCL showed a lower NAA / (Cr + Cho) ratio in the left cingulate (0.78 ± 0.05) than the controls (0.95 ± 0.02, P < 0.05) and the subgroup with normal SCL (0.88 ± 0.03, P < 0.05). There was a negative correlation between the NAA / (Cr + Cho) ratio in the left cingulate of patients with schizophrenia and the duration of the disease and years under medication. These data suggest the existence of a schizophrenic subgroup characterized by low SCL that could be a consequence of the lower neuronal viability observed in the left cingulate of these patients.
Subject(s)
Adult , Female , Humans , Male , Aspartic Acid/analogs & derivatives , Cerebral Cortex/chemistry , Choline/analysis , Creatine/analysis , Galvanic Skin Response/physiology , Schizophrenia/metabolism , Acoustic Stimulation , Aspartic Acid/analysis , Case-Control Studies , Magnetic Resonance Spectroscopy/methods , Protons , Socioeconomic Factors , Schizophrenia/physiopathologyABSTRACT
OBJECTIVE: The results for finding the deficit in the anterior cingulate (ACC) in schizophrenic patients (SZ) have been inconsistent according to the studies that used different Stroop tasks, which is unlike the deficit in the dorsolateral prefrontal cortex (DLPFC). In order to explore for the core region that's responsible for the selective attention deficit in SZ, we examined the results of a functional neuroimaging study, which involved the performance of the Stroop task using high or low prefrontal cortex related loads in SZ. METHODS: Ten schizophrenic patients and healthy controls (HC) received functional magnetic resonance imaging (fMRI) during a Short/Long-term latency Stroop task. The changes in the neural activity were determined in well-known Stroop related regions of interest (ROIs) that consisted of the DLPFC, ACC, the parietal lobule and in the whole brain regions for both the main and interaction effects of latency, and the results of the short-term and long-term latency Stroop conditions were compared. RESULTS: The response times for both the congruency and latency effects were more prolonged in the schizophrenics than in the HC. For the congruency effect, the schizophrenics showed significantly less activation in the same site of the left DLPFC in both the short-term and long-term latency conditions, as compared with the HC. For the latency effect, the regions of the left-side language network were over- or under-activated in the schizophrenics, as compared with the HC. Any interaction effect was not found for both the behavioral and fMRI results. CONCLUSION: Our results indicate that the deficit in the left DLPFC is the core impairment of attentional processing in schizophrenics, regardless of other possible interactions such as the latency effect.