Brain morphological changes and functional neuroanatomy related to cognitive and emotional distractors during working memory maintenance in post-traumatic stress disorder

This study utilized functional magnetic resonance imaging (fMRI) to discriminate brain activation patterns associated with the effect of distraction during working memory (WM) maintenance for human faces in healthy controls and patients with schizophrenia. Event-related fMRI data were obtained while the subjects performed WM maintenance in a delayed-response WM task with task-irrelevant distracters. Compared with healthy controls, patients showed significantly decreased activities in the superior frontal gyrus, dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex, anterior cingulate cortex, inferior parietal gyrus, and fusiform gyrus during the delayed-response WM task with human face distracters. The blood-oxygen-level-dependent signal changes in the DLPFC were negatively correlated with both of the scores of the Positive Subscale and General Psychopathology Subscale under the Positive and Negative Syndrome Scale during the WM maintenance for the human faces in the patients. This study will be helpful in understanding the neural mechanisms in the general impairment of the inhibition control in schizophrenia.

Emotional Reactivity in Posttraumatic Stress Disorder:Behavioural and Neurobiological Correlates of Underlying Mechanisms and the Role of Emotional Memory Modification

Alterations of the topological organization of abnormal regions or network-level structural aberrations are still poorly understood for post-traumatic stress disorder (PTSD). Herein, we investigated brain structural networks in recent-onset PTSD patients, all affected by the coalmine-flood disaster. Cortical networks were studied in recent onset PTSD patients (n=15) and matched healthy controls (n=25). Cortical networks were constructed by thresholding correlation matrices of 150 regions and quantified using graph theoretical approaches. Contributions of high-degree nodes, and regional and global network measures, including degree and betweenness, were studied. Compared with healthy controls, PTSD patients showed altered quantitative values in global network properties, characterized by shorter path length and higher clustering. Moreover, PTSD patients exhibited decreased connectivity in the right lingual gyrus, parahippocampal gyrus, left supramarginal gyrus, parahippocampal gyrus, bilateral superior and inferior frontal gyrus, superior frontal gyrus, and posterior cingulate gyrus. Nodal centrality decreased predominantly in the occipital regions (lingual gyrus) and default-mode regions, while increased correlations and centralities were observed in the medial temporal lobe and posterior cingulate cortex. PTSD-related networks exhibited a less efficient organization and regional connectivity. According to these findings, we conclude that regional connections involving fear-processing and re-experiential-processing cortex may play a role in maintaining or adapting to PTSD pathology.

Meta-analysis of post-traumatic stress disorder and COVID-19 in patients discharged

ObjectiveThe neural correlates underlying the effects of emotional distraction during working memory (WM) tasks in patients with schizophrenia have yet to be clearly identified. Thus, the present study employed functional magnetic resonance imaging (fMRI) to investigate the effects of emotional distraction involving fear during WM maintenance in patients with schizophrenia.MethodsThis study included 17 patients with schizophrenia who were diagnosed based on Diagnostic and Statistical Manual of Mental Disorders fourth edition, text revision (DSM-IV-TR) criteria and 17 matched healthy controls. Event-related fMRI data were acquired while the participants performed a delayed-response WM task that included neutral and fearful distractors.ResultsPatients with schizophrenia may have tried to maintain WM function during the presentation of task-irrelevant fearful distractors that induced interruption and required attention. Compared to healthy controls, the schizophrenia patients exhibited significantly increased activity in the dorsolateral prefrontal cortex, medial prefrontal cortex, superior temporal gyrus, middle temporal gyrus, insula, hippocampus, caudate nucleus, and postcentral gyrus in a delayed-response WM task when presented with fearful relative to neutral distractors. In addition to its series of increased brain activations, prefrontal areas exhibited interconnections with more caudal brain regions, including temporal areas and the hippocampus and insula.ConclusionThe present study identified specific brain areas associated with the interaction between emotional regulation and cognitive functioning during fearful distractors presented while patients with schizophrenia performed a WM maintenance task. These findings further the current understanding of the neural correlates underlying the effects of emotional distraction on cognitive functioning in patients with schizophrenia.

BackgroundPatients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group.MethodsT1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9).ResultsPTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges’ g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges’ g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (pcorrected = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (pcorrected = .001).ConclusionsPTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.

PTSD and Combat-Related Injuries: Functional Neuroanatomy

This study aimed to investigate the association between changes in brain volumes and memory task-based functional connectivity (FC) patterns in patients with posttraumatic stress disorder (PTSD) compared to healthy controls (HCs). This study employed voxel-based morphometry and task-based functional magnetic resonance imaging using memory task to examine alterations in brain volume density and FC within and between relevant brain regions involved in memory processes such as encoding and retrieval. PTSD patients exhibited increased brain volumes in the right cerebellum (Cb) in the gray matter (GM) region compared to HCs. Analysis of FC patterns revealed that both groups exhibited similar connectivity patterns, but PTSD patients displayed higher and more extensive interregional connectivity relative to HCs. During the memory encoding process, PTSD patients exhibited higher FC linked to the Cb in the right postcentral gyrus, left precentral gyrus (PrCG), left orbito frontal gyrus (OFG), and superior frontal gyrus, while demonstrating lower connectivity in the right hippocampus. In the memory retrieval period, PTSD patients showed higher FC in the right middle frontal gyrus, left middle occipital gyrus, left OFG, right inferior parietal gyrus, and right PrCG, along with lower FC in the right/left inferior frontal gyrus and right superior parietal gyrus. Additionally, a negative correlation was observed between PTSD symptom severity and local GM volumes in the right Cb. However, no significant correlation was found with FC. Our findings provide insights into the specific alterations in brain structure and connectivity associated with PTSD, contributing to a better understanding of the underlying neural mechanisms of PTSD.

Neuroanatomical Mechanism for the Influence of Emotional Distracter On Working Memory Maintenance in Patients with Schizophrenia Using Functional Mri

Individuals with depression display abnormal modulation of neural oscillatory activity during working memory encoding and maintenance

Few studies have assessed the neural mechanisms of the effects of emotion on cognition in generalized anxiety disorder (GAD) patients. In this functional MRI (fMRI), we investigated the effects of emotional interference on working memory (WM) maintenance in GAD patients. Fifteen patients with GAD participated in this study. Event-related fMRI data were obtained while the participants performed a WM task (face recognition) with neutral and anxiety-provoking distracters. The GAD patients showed impaired performance in WM task during emotional distracters and showed greater activation on brain regions such as DLPFC, VLPFC, amygdala, hippocampus which are responsible for the active maintenance of goal relevant information in WM and emotional processing. Although our results are not conclusive, our finding cautiously suggests the cognitive-affective interaction in GAD patients which shown interfering effect of emotional distracters on WM maintenance.

Back to table of contents Previous article Next article Clinical & Research NewsFull AccessNeural Network Relationships Differ in PTSD PatientsAaron LevinAaron LevinSearch for more papers by this authorPublished Online:16 Apr 2010https://doi.org/10.1176/pn.45.8.psychnews_45_8_025AbstractThe most familiar analogy to the brain is usually the computer, but that's so 20th century now.In fact, the brain may work more like that 21st-century technology, the hybrid car. The hybrid has two engines under that sleek hood, one running on gasoline when the car needs power and the other on electricity when moving slowly or cruising or idling.The two “engines” in the brain are actually groups of brain regions. One group constitutes the central executive network and handles the heavy lifting during cognitive tasks, when neural activity increases in the “task-positive” regions, the frontal motor areas, dorsolateral prefrontal cortex, and dorsal anterior cingulate gyrus.Neural activity decreases, however, during cognitive tasks in other, “task negative” regions that define the default-mode network.“The default-mode network is active when the person is not focused on the external environment,” said Ruth Lanius, M.D., Ph.D., at the Anxiety Disorders Association of America's annual conference in Baltimore in March. “It operates when individuals are engaged in internally focused tasks, like autobiographical memory retrieval, envisioning the future, and conceiving the perspectives of others.”It may serve to consolidate and stabilize memories for later processing.Network Operations Reflect PTSDThe two networks and the relationship between them may also have something to do with posttraumatic stress disorder (PTSD), said Lanius, an associate professor in the Department of Psychiatry at Canada's University of Western Ontario.For one thing, the default network and PTSD both seem associated with the same areas of the brain such as the medial prefrontal cortex, anterior cingulate, and posterior cingulate cortex.Lanius's brain-imaging studies of 12 accident victims found that connectivity involving some of these areas was associated with current PTSD symptoms or predicted such symptoms at 12 weeks after the accident.A second relationship between the executive and default networks may be reflected in how the brain switches from one to the other, she said.In working-memory tasks, healthy control subjects show more activity in the central executive network compared with those with PTSD. The PTSD group may have more difficulty engaging the executive network, and so moving out of the default-mode network and into cognitive tasks becomes more difficult.The subjects with PTSD in Lanius's study showed stronger connectivity between the prefrontal cingulate cortex and the right superior frontal gyrus and between the medial prefrontal cortex and the left parahippocampal gyrus, areas previously implicated in the default-mode network.The different connectivity patterns and neural networks used by the controls, compared with the PTSD subjects, suggest group differences in orientation during a working-memory task and difficulties switching between the two networks, she concluded.Lanius's next step is to replicate the findings in a larger sample and explore more regions of the brain. She will also compare patients whose PTSD is associated with early-life trauma with those who developed the disorder as adults.Responses to Danger Cues DifferIn another talk, National Institute of Mental Health researcher Shmuel Lissek, Ph.D., reported on research relating fear conditioning to PTSD.He uses psychological tests to reveal the subjects' responses to conditioned danger cues and conditioned safety cues arrayed on a gradient. The safety cue was a small circle. The danger cue was a large circle accompanied by a “highly uncomfortable but not painful” electric shock to the wrist.The subjects saw a circle—large, small, or in between—on a computer screen. In healthy controls, the response to the danger cue was greater than that to the safety cue. The PTSD patients, however, showed elevated responses even as the circles declined in size toward the safety end of the continuum.“The controls had a higher discrimination between safety and danger, while the PTSD patients had poorer discrimination,” said Lissek. “They overrespond to safety cues that resemble danger cues.”Thus the PTSD patients generalized their danger response to stimuli well beyond that of actual danger, he said. “There is a strong persistence of danger response even as the conditioned danger cue declines.”Also, the control subjects responded with more hesitation to intermediate cues, indicating greater uncertainty in discriminating threat from danger. The subjects with PTSD had much faster reaction times to those intermediate cues, implying that overgeneralization may be a marker for PTSD.Lissek said that these results should be considered preliminary since he is still gathering data, but that they do indicate new paths for research. ISSUES NewArchived

The concept of acute stress disorder (ASD) was introduced as a diagnostic entity to improve the identification of traumatized people who are likely to develop posttraumatic stress disorder (PTSD). Neuroanatomical models suggest that changes in the prefrontal cortex, amygdala, and hippocampus play a role in the development of PTSD. Using voxel-based morphometry, this study aimed to investigate the predictive power of gray matter volume (GMV) alterations for developing PTSD. The GMVs of ASD patients (n = 21) were compared to those of PTSD patients (n = 17) and healthy controls (n = 18) in whole-brain and region-of-interest analyses. The GMV alterations seen in ASD patients shortly after the traumatic event (T1) were also correlated with PTSD symptom severity and symptom clusters 4weeks later (T2). Compared with healthy controls, the ASD patients had significantly reduced GMV in the left visual cortex shortly after the traumatic event (T1) and in the left occipital and prefrontal regions 4weeks later (T2); no significant differences in GMV were seen between the ASD and PTSD patients. Furthermore, a significant negative association was found between the GMV reduction in the left lateral temporal regions seen after the traumatic event (T1) and PTSD hyperarousal symptoms 4weeks later (T2). Neither amygdala nor hippocampus alterations were predictive for the development of PTSD. These data suggest that gray matter deficiencies in the left hemispheric occipital and temporal regions in ASD patients may predict a liability for developing PTSD.

This study compared the difference in brain structure in 12 mine disaster survivors with chronic post-traumatic stress disorder, 7 cases of improved post-traumatic stress disorder symptoms, and 14 controls who experienced the same mine disaster but did not suffer post-traumatic stress disorder, using the voxel-based morphometry method. The correlation between differences in brain structure and post-traumatic stress disorder symptoms was also investigated. Results showed that the gray matter volume was the highest in the trauma control group, followed by the symptoms-improved group, and the lowest in the chronic post-traumatic stress disorder group. Compared with the symptoms-improved group, the gray matter volume in the lingual gyrus of the right occipital lobe was reduced in the chronic post-traumatic stress disorder group. Compared with the trauma control group, the gray matter volume in the right middle occipital gyrus and left middle frontal gyrus was reduced in the symptoms-improved group. Compared with the trauma control group, the gray matter volume in the left superior parietal lobule and right superior frontal gyrus was reduced in the chronic post-traumatic stress disorder group. The gray matter volume in the left superior parietal lobule was significantly positively correlated with the State-Trait Anxiety Inventory subscale score in the symptoms-improved group and chronic post-traumatic stress disorder group (r = 0.477, P = 0.039). Our findings indicate that (1) chronic post-traumatic stress disorder patients have gray matter structural damage in the prefrontal lobe, occipital lobe, and parietal lobe, (2) after post-traumatic stress, the disorder symptoms are improved and gray matter structural damage is reduced, but cannot recover to the trauma-control level, and (3) the superior parietal lobule is possibly associated with chronic post-traumatic stress disorder. Post-traumatic stress disorder patients exhibit gray matter abnormalities.

The authors aim to delineate cognitive dysfunction associated with posttraumatic stress disorder (PTSD) by evaluating a well-defined cohort of former World War II prisoners of war (POWs) with documented trauma and minimal comorbidities. The authors studied a cross-sectional assessment of neuropsychological performance in former POWs with PTSD, PTSD with other psychiatric comorbidities, and those with no PTSD or psychiatric diagnoses. Participants who developed PTSD had average IQ, while those who did not develop PTSD after similar traumatic experiences had higher IQs than average (approximately 116). Those with PTSD performed significantly less well in tests of selective frontal lobe functions and psychomotor speed. In addition, PTSD patients with co-occurring psychiatric conditions experienced impairment in recognition memory for faces. Higher IQ appears to protect individuals who undergo a traumatic experience from developing long-term PTSD, while cognitive dysfunctions appear to develop with or subsequent to PTSD. These distinctions were supported by the negative and positive correlations of these cognitive dysfunctions with quantitative markers of trauma, respectively. There is a suggestion that some cognitive decrements occur in PTSD patients only when they have comorbid psychiatric diagnoses.