A review of neuroimaging studies in PTSD: heterogeneity of response to symptom provocation

Mild traumatic brain injury: longitudinal regional brain volume changes

PURPOSE

To investigate longitudinal changes in global and regional brain volume in patients 1 year after mild traumatic brain injury (MTBI) and to correlate such changes with clinical and neurocognitive metrics.

MATERIALS AND METHODS

This institutional review board-approved study was HIPAA compliant. Twenty-eight patients with MTBI (with 19 followed up at 1 year) with posttraumatic symptoms after injury and 22 matched control subjects (with 12 followed up at 1 year) were enrolled. Automated segmentation of brain regions to compute regional gray matter (GM) and white matter (WM) volumes was performed by using three-dimensional T1-weighted 3.0-T magnetic resonance imaging, and results were correlated with clinical metrics. Pearson and Spearman rank correlation coefficients were computed between longitudinal brain volume and neurocognitive scores, as well as clinical metrics, over the course of the follow-up period.

RESULTS

One year after MTBI, there was measurable global brain atrophy, larger than that in control subjects. The anterior cingulate WM bilaterally and the left cingulate gyrus isthmus WM, as well as the right precuneal GM, showed significant decreases in regional volume in patients with MTBI over the 1st year after injury (corrected P < .05); this was confirmed by means of cross-sectional comparison with data in control subjects (corrected P < .05). Left and right rostral anterior cingulum WM volume loss correlated with changes in neurocognitive measures of memory (r = 0.65, P = .005) and attention (r = 0.60, P = .01). At 1-year follow-up, WM volume in the left cingulate gyrus isthmus correlated with clinical scores of anxiety (Spearman rank correlation r = -0.68, P = .007) and postconcussive symptoms (Spearman rank correlation r = -0.65, P = .01).

CONCLUSION

These observations demonstrate structural changes to the brain 1 year after injury after a single concussive episode. Regional brain atrophy is not exclusive to moderate and severe traumatic brain injury but may be seen after mild injury. In particular, the anterior part of the cingulum and the cingulate gyrus isthmus, as well as the precuneal GM, may be distinctively vulnerable 1 year after MTBI.

Overgeneralized autobiographical memory and future thinking in combat veterans with posttraumatic stress disorder

BACKGROUND

Studies show that individuals with Posttraumatic Stress Disorder (PTSD) tend to recall autobiographical memories with decreased episodic specificity. A growing body of research has demonstrated that the mechanisms involved in recalling autobiographical memories overlap considerably with those involved in imagining the future. Although shared autobiographical deficits in remembering the past and imagining the future have been observed in other clinical populations, this has yet to be examined in PTSD. This study examined whether, compared to combat trauma-exposed individuals without PTSD, those with combat-related PTSD would be more likely to generate overgeneralized autobiographical memories and imagined future events.

METHOD

Operation Enduring/Iraqi Freedom (OEF/OIF) veterans with and without PTSD were presented with neutral word cues and were instructed to generate memories or imagine future autobiographical events. Responses were digitally recorded and were coded for level of episodic specificity and content related to combat trauma.

RESULTS

Individuals with PTSD were more likely to generate overgeneral autobiographical memories and future events than individuals without PTSD, and were more likely to incorporate content associated with combat when remembering the past or thinking about the future.

LIMITATION

Limitations of the study include a cross-sectional design, precluding causality; the lack of a non-trauma exposed group, relatively small sample, and almost all-male gender of participants, limiting the generalizability to other populations.

CONCLUSION

These findings suggest that individuals with PTSD show similar deficits when generating personal past and future events, which may represent a previously unexamined mechanism involved in the maintenance of PTSD symptoms.

Trauma-related reactivity and regulation of emotion: associations with posttraumatic stress symptoms

BACKGROUND AND OBJECTIVES

Both emotional reactivity to traumatic event cues and difficulties regulating emotion have been linked to posttraumatic stress symptom severity. The current study uniquely extended these two lines of research by examining the degree to which these two factors alone, and in combination, account for variability in posttraumatic stress symptom severity.

METHOD

Self-reported emotion regulation difficulties, and both subjective and physiological reactivity in response to a script-driven imagery procedure, were assessed among a community sample of 21 adult women with a history of interpersonal assault. Relationships with an interview-based measure of posttraumatic stress symptom severity were examined.

RESULTS

Results were consistent with hypotheses. Both traumatic event-related emotional reactivity and emotion regulation difficulties independently predicted posttraumatic stress symptom severity. A significant interaction also emerged such that traumatic event-related emotional reactivity and posttraumatic stress symptom severity were only significantly associated at relatively elevated levels of emotion regulation difficulties.

LIMITATIONS

Limitations included the use of a self-report questionnaire to assess emotion regulation difficulties, relatively small sample size, and lack of evidence regarding generalizability across gender or other traumatic event types.

CONCLUSIONS

These results highlight that the interaction of heightened emotional reactivity and difficulties regulating emotion may be particularly influential in posttraumatic stress symptom severity.

Neural functional and structural correlates of childhood maltreatment in women with intimate-partner violence-related posttraumatic stress disorder

Childhood maltreatment (CM) is a strong risk factor for development of posttraumatic stress disorder (PTSD) upon adult exposure to extreme adverse events. However, the neural underpinnings of this relationship are not well understood. Here, we test the hypothesis that severity of CM history is positively correlated with emotion-processing limbic and prefrontal brain activation/connectivity and negatively correlated with prefrontal gray matter volumes in women with PTSD due to intimate-partner violence (IPV-PTSD). Thirty-three women with IPV-PTSD underwent structural and functional magnetic resonance imaging while completing a facial emotion processing task. Multivariate regressions examined the relationship of CM to patterns of activation, connectivity, and gray matter volumes. CM severity was: (a) positively correlated with ventral ACC activation while processing angry faces; (b) negatively correlated with dorsal ACC and insula activation while processing fear and angry faces, arising from positive correlations with the shape-matching baseline; (c) positively correlated with limbic-prefrontal connectivity while processing fear faces but negatively correlated with amygdalo-insular connectivity while processing fear and angry; and (d) negatively correlated with prefrontal gray matter volumes. These results suggest CM exposure may account for variability in limbic/prefrontal brain function and prefrontal structure in adulthood PTSD and offer one potential mechanism through which CM confers risk to future development of PTSD.

Neural systems for cognitive and emotional processing in posttraumatic stress disorder

Individuals with posttraumatic stress disorder (PTSD) show altered cognition when trauma-related material is present. PTSD may lead to enhanced processing of trauma-related material, or it may cause impaired processing of trauma-unrelated information. However, other forms of emotional information may also alter cognition in PTSD. In this review, we discuss the behavioral and neural effects of emotion processing on cognition in PTSD, with a focus on neuroimaging results. We propose a model of emotion-cognition interaction based on evidence of two network models of altered brain activation in PTSD. The first is a trauma-disrupted network made up of ventrolateral PFC, dorsal anterior cingulate cortex (ACC), hippocampus, insula, and dorsomedial PFC that are differentially modulated by trauma content relative to emotional trauma-unrelated information. The trauma-disrupted network forms a subnetwork of regions within a larger, widely recognized network organized into ventral and dorsal streams for processing emotional and cognitive information that converge in the medial PFC and cingulate cortex. Models of fear learning, while not a cognitive process in the conventional sense, provide important insights into the maintenance of the core symptom clusters of PTSD such as re-experiencing and hypervigilance. Fear processing takes place within the limbic corticostriatal loop composed of threat-alerting and threat-assessing components. Understanding the disruptions in these two networks, and their effect on individuals with PTSD, will lead to an improved knowledge of the etiopathogenesis of PTSD and potential targets for both psychotherapeutic and pharmacotherapeutic interventions.

Etiopathogenic perspectives on chronic psycho traumatic and chronic psychotic symptoms: the hypothesis of a hyperdopaminergic endophenotype of PTSD

Post traumatic stress disorder (PTSD) is a complex and heterogeneous disorder, which specific symptoms are re-experiencing, increased arousal and avoidance of stimuli associated with the trauma. PTSD has much comorbidity like depression, substance abuse, somatic complaints, repeated dissociative phenomena and transitory or chronic psychotic reactions. PTSD can manifest itself in different clinical forms: some patients present higher symptoms in one domain as compared to another, probably because of abnormalities in different neurobiological systems. Hyposerotonergic and hypernoradrenergic PTSD endophenotypes have been previously identified and the purpose of this paper is to focus on the hypothesis of a hyperdopaminergic endophenotype. The current review discusses several entities: PTSD with psychotic features with or without depression, the comorbide use of psychoactive substances that increase psychotic symptoms and traumatic brain injuries as agents of psycho traumatic and psychotic features. For all of these nosographic entities, the dopaminergic neuromodulation may play a central role. The hypothesis of a hyperdopaminergic endophenotype of PTSD opens up new research and therapeutic perspectives. Although antipsychotics are frequently used for people with PTSD further studies are needed to develop a consensus on the guidelines for treating the psychotic forms of PTSD.

Evidence for a dissociative subtype of PTSD by latent profile and confirmatory factor analyses in a civilian sample

BACKGROUND

Dissociative symptoms are increasingly recognized in individuals with posttraumatic stress disorder (PTSD). The aim of this study was to investigate the prevalence of derealization and depersonalization symptoms via latent profile analyses (LPAs) in a civilian PTSD sample and examine the relationship between PTSD and dissociative symptoms via factor analytic methods.

METHODS

A civilian sample of individuals with PTSD predominantly related to childhood abuse (n = 134) completed a diagnostic interview for PTSD and comorbid psychiatric disorders. LPAs and confirmatory factor analyses (CFAs) were performed on the severity scores for PTSD, derealization, and depersonalization symptoms.

RESULTS

LPAs extracted three groups, one of which was uniquely characterized by high derealization and depersonalization symptoms, and accounted for 25% of the sample. Individuals in the dissociative subgroup also showed a higher number of comorbid Axis I disorders and a more significant history of childhood abuse and neglect. CFAs suggested the acceptance of a five factor solution in which dissociative symptoms are distinct from but correlate significantly with the core PTSD symptom clusters.

CONCLUSIONS

The results from LPAs and CFAs are concordant with the concept of a dissociative subtype in patients with PTSD and suggest that symptoms of derealization-depersonalization and the core symptoms of PTSD are positively correlated. Thought should be given to including a dissociative subtype of PTSD in the DSM-5.

The dissociative subtype of posttraumatic stress disorder: rationale, clinical and neurobiological evidence, and implications

BACKGROUND

Clinical and neurobiological evidence for a dissociative subtype of posttraumatic stress disorder (PTSD) has recently been documented. A dissociative subtype of PTSD is being considered for inclusion in the forthcoming Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) to address the symptoms of depersonalization and derealization found among a subset of patients with PTSD. This article reviews research related to the dissociative subtype including antecedent, concurrent, and predictive validators as well as the rationale for recommending the dissociative subtype.

METHODS

The relevant literature pertaining to the dissociative subtype of PTSD was reviewed.

RESULTS

Latent class analyses point toward a specific subtype of PTSD consisting of symptoms of depersonalization and derealization in both veteran and civilian samples of PTSD. Compared to individuals with PTSD, those with the dissociative subtype of PTSD also exhibit a different pattern of neurobiological response to symptom provocation as well as a differential response to current cognitive behavioral treatment designed for PTSD.

CONCLUSIONS

We recommend that consideration be given to adding a dissociative subtype of PTSD in the revision of the DSM. This facilitates more accurate analysis of different phenotypes of PTSD, assist in treatment planning that is informed by considering the degree of patients' dissociativity, will improve treatment outcome, and will lead to much-needed research about the prevalence, symptomatology, neurobiology, and treatment of individuals with the dissociative subtype of PTSD.

Neurocircuitry models of posttraumatic stress disorder and beyond: a meta-analysis of functional neuroimaging studies

Over the past two decades a relatively large number of studies have investigated the functional neuroanatomy of posttraumatic stress disorder (PTSD). However, findings are often inconsistent, thus challenging traditional neurocircuitry models of PTSD. As evidence mounts that cognition and behavior is an emergent property of interacting brain networks, the question arises whether PTSD can be understood by examining dysfunction in large-scale, spatially distributed neural networks. We used the activation likelihood estimation quantitative meta-analytic technique to synthesize findings across functional neuroimaging studies of PTSD that either used a non-trauma (N=20) or trauma-exposed (N=19) comparison control group. In line with neurocircuitry models, our findings support hyperactive amygdala and hypoactive medial prefrontal regions, but suggest hyperactive hippocampi. Characterization of additional regions under a triple network model showed functional alterations that largely overlapped with the salience network, central executive network, and default network. However, heterogeneity was observed within and across the neurocircuitry and triple network models, and between results based on comparisons to non-trauma and trauma-exposed control groups. Nonetheless, these results warrant further exploration of the neurocircuitry and large-scale network models in PTSD using connectivity analyses.

Temporal analysis of heart rate variability as a predictor of post traumatic stress disorder in road traffic accidents survivors

BACKGROUND

Road Traffic Accidents (RTA) are most probably the leading cause of post traumatic stress disorder (PTSD) in developed countries. The autonomic nervous system (ANS) disturbances, due to psychological trauma, are part of the pathophysiology of PTSD. The aim of the present study was to determine whether early heart rate variability (HRV) measurement, a biomarker of the ANS function, could act as a predictor of PTSD development after a RTA.

METHODS

We prospectively investigated 35 survivors of RTA with both physical injury and psychological trauma. HRV data were obtained from 24-h Holter ECG monitoring, which was performed on the second day after the accident. Time domain analysis was applied to the inter-beat (RR) interval time series to calculate the various parameters of HRV. PTSD status was assessed 2 and 6 months after RTA.

RESULTS

There was a global diminution of HRV measurements in the PTSD group at both 2 and 6 months. The variability index was the best predictor of PTSD with the area under the receiveroperating curve for discriminating PTSD at 6 months at 0.92 (95% CI: 0.785; 1.046). A cut-off at 2.19% yielded a sensitivity of 85.7% and a specificity of 81.8% for PTSD. Positive and negative predictive values were respectively 75% and 90%. However, initial heart rate (HR) data were relevant at 2 months but not at 6 months.

CONCLUSION

RTA survivors exhibiting lower parasympathetic modulation of HR, indexed by temporal analysis of HRV, are more susceptible to developing PTSD as a short and long-term outcome.

Using novel methods to examine stress among HIV-positive African American men who have sex with men and women

Biomarker composites (BCs) that objectively quantify psychosocial stress independent of self report could help to identify those at greatest risk for negative health outcomes and elucidate mechanisms of stress-related processes. Here, BCs are examined in the context of existing disease progression among HIV-positive African American men who have sex with men and women (MSMW) with high stress histories, including childhood sexual abuse. Participants (N = 99) collected 12-h overnight and morning urine samples for assay of cortisol and catecholamines (primary BC) and neopterin (an indicator of HIV disease progression). Data on cumulative psychosocial trauma history (severity, types, frequency, age at first incident), posttraumatic stress disorder (PTSD) symptoms, sexual risk behaviors, and a secondary BC consisting of routine health indicators (heart rate, blood pressure, body mass index, waist-to-hip ratio) were also collected. Lifetime trauma exposure was highly pervasive and significantly greater among those meeting a standard cutoff for PTSD caseness (24 %). After controlling for HIV factors (neopterin levels and years with disease), PTSD was a significant (p < .05) predictor of the primary, but not secondary BC. Those with PTSD also had significantly more sexual partners, sex without a condom, and exchange sex for money or drugs than those without PTSD. Specific trauma characteristics predicted PTSD severity and caseness independently and uniquely in regression models (p's < .05-.001). A primary BC appears sensitive to cumulative trauma burden and PTSD in HIV-positive African American MSMW, providing support for the use of BCs to quantify psychosocial stress and inform novel methods for examining mechanisms of stress influenced health behaviors and disease outcomes in at-risk populations.

Emotional stress and heart rate variability measures associated with cardiovascular risk in relocated Katrina survivors

OBJECTIVE

To explore the effects of hurricane exposure and forced relocation on the mind and body, we compared psychiatric diagnoses and symptoms with heart rate variability (HRV) for 34 relocated Katrina survivors and 34 demographically matched controls.

METHODS

All participants were healthy and free of psychiatric and cardiovascular medications. We measured symptoms of posttraumatic stress disorder (PTSD) (Clinician-Administered PTSD Scale 1) and depression (Beck Depression Inventory), Axis I psychiatric diagnoses (Structured Clinical Interview for DSM-IV), psychosocial disability (Sheehan Disability Scale), and power spectral analysis HRV reactivity to trauma reminders.

RESULTS

Katrina-related PTSD occurred in 38% of survivors and 12% of controls. Survivors reported higher levels of PTSD and depression symptoms, within diagnostic ranges, and greater psychosocial disability than controls. Survivors had higher resting heart rate (80.82 [standard deviation = 13.60] versus 74.85 [10.67], p = .05), lower parasympathetic (high-frequency [HF] normalized unit) baseline HRV activity (40.14 [23.81] versus 50.67 [19.93], p = .04) and less reactivity with trauma cues (-2.63 [20.70] versus -11.96 [15.84], p = .04), and higher baseline sympathovagal activity (low frequency/HF ratio) (2.84 [3.08] versus 1.35 [1.08], p = .04) than controls. Survivors with depression (n = 12) and with depression and PTSD combined (n = 7), but not those with PTSD (n = 13), had flattened parasympathetic responsiveness to trauma cues. HRV indices correlated with depressive (low frequency/HF, p = .01; HF normalized unit, p = .046) but not PTSD symptoms (p values > .05).

CONCLUSIONS

Results showed this multilayer trauma's impact on emotional health and HRV-based measures of autonomic nervous system dysregulation. Specifically, dysregulation of depressed survivors' HRV in response to trauma reminders supports more autonomic involvement in traumatic loss/depression than in PTSD. Diagnostic criteria for PTSD include physiologic reactivity, and the present findings suggest that, in this setting, altered physiologic reactivity observed when PTSD coexists with depression.

Victims of rape show increased cortisol responses to trauma reminders: a study in individuals with war- and torture-related PTSD

Studies investigating cortisol responses to trauma-related stressors in patients with posttraumatic stress disorder (PTSD) have yielded inconsistent results, demonstrating that cortisol responses were enhanced or unaffected when confronted with trauma reminders. This study investigated the effect of the type of trauma experienced on both salivary and plasma cortisol responses during confrontation with trauma-related material. Participants were 30 survivors of war and torture, with and without rape among the traumatic events experienced. Participants of both groups (raped vs. non-raped) fulfilled DSM-IV criteria of PTSD. Plasma and salivary cortisol levels were measured at three time points during a standardized clinical interview: once before and twice after assessing individual traumatic experiences. Results show that groups did not differ in basal plasma and salivary cortisol levels. However, differential salivary cortisol responses were observed in PTSD patients who had been raped compared to those who had not been raped (p<.05) but had experienced an equal number of traumatic events and showed equally high PTSD symptom severity. Whereas salivary cortisol levels decreased in the course of the interview for the group with no past experience of rape (p<.05), those PTSD patients who had been raped showed a significant cortisol increase when reminded of their traumatic events (p<.001). This effect was not found in plasma cortisol. Our results indicate that the type of traumatic stress experienced contributes to cortisol responses during the confrontation with trauma-related material. We hypothesize, that the nearness of the perpetrator during the traumatic event might shape later psychophysiological responding to trauma reminders.

Peritraumatic dissociation and peritraumatic emotional predictors of PTSD in Latino youth: results from the Hispanic family study

This is the 1st study to examine peritraumatic dissociation and peritraumatic emotions as they predict symptoms and diagnosis of posttraumatic stress disorder (PTSD) in Latino youth. Our aim was to test the hypothesis that the degree of peritraumatic dissociation would predict the number of PTSD symptoms and PTSD clinical diagnosis when the influences of other salient factors were statistically controlled. We also explored the possible contributions of peritraumatic emotional responses to PTSD symptomatology and PTSD diagnosis. We expected that peritraumatic dissociation would emerge as a significant predictor of PTSD. A total of 204 Latino youth (mean age = 12.37 years) completed semistructured individual clinical interviews with bilingual research assistants. These interviews assessed trauma exposure, peritraumatic responses, and current psychopathology. A linear regression analysis demonstrated significant relationships between lifetime number of traumatic events, peritraumatic dissociation, shame, and number of PTSD symptoms endorsed. Significant inverse (protective) relationships were demonstrated between anger and guilt and current PTSD symptomatology. Logistic regression analysis demonstrated significant relationships between peritraumatic dissociation, shame, lifetime number of traumatic events experienced, and PTSD diagnosis. The analyses examined both the number of PTSD symptoms as well as diagnosis of PTSD while simultaneously controlling for age, lifetime exposure to traumatic events, time residing in the United States, and gender. These results support an increasingly robust body of empirical literature suggesting that the peritraumatic dissociative and emotional responses to trauma are important predictors of future PTSD diagnosis. Possible cultural factors contributing to the dissociative responses in Latino youth and clinical implications are discussed.

Psychophysiological investigations in depersonalization disorder and effects of electrodermal biofeedback

Previous studies investigating depersonalization disorder (DPD) report a lower baseline skin conductance level (SCL) and attenuated skin conductance response (SCR) to emotive stimuli. We hypothesized that increasing physiological arousal levels via electrodermal biofeedback may ameliorate disembodiment and emotional numbing symptomatology. Real-time versus sham biofeedback yielded a significant SCL increase after just 3 real-time biofeedback sessions in healthy volunteers. Subsequently, a randomized controlled biofeedback trial was administered with DPD patients. Findings were not replicated as SCL tended to fall, curiously more substantially in the real-time condition, concomitant with increased low- and high-frequency heart rate variability. To further investigate abnormal autonomic regulation in DPD, we compared basal autonomic activity between patients and healthy volunteers and found the former to be significantly more labile, indexed by greater nonspecific SCRs and higher resting SCLs. Rather than low sympathetic arousal, DPD might be better characterized by abnormal autonomic regulation affecting emotional and physiological responsivity.

Prior peritraumatic dissociative experiences affect autonomic reactivity during trauma recall

To better understand the psychophysiological correlates of peritraumatic dissociation (PD), the present study examined the relationship between reports of prior PD and sympathetic and parasympathetic functioning in response to a laboratory stress paradigm in 39 traumatized female undergraduates. Participants were asked to talk about their most distressing traumatizing experience while continuous measures of heart rate, pre-ejection period, and respiratory sinus arrhythmia were taken. Overall, high dissociators had significantly larger increases in heart rate and larger decreases in pre-ejection period and respiratory sinus arrhythmia during trauma recall. In opposition to our hypothesis, these results suggest that female trauma victims reporting high levels of PD during a prior trauma may be more reactive to traumatic reminders than victims who report lower levels of PD.

Relationships among childhood trauma, posttraumatic stress disorder, and dissociation in men living with HIV/AIDS

This study examined the relationships among dissociation, childhood trauma and sexual abuse, and posttraumatic stress disorder (PTSD) symptoms in HIV-positive men. Data were collected from 167 men enrolled in a randomized clinical trial that examined a group therapy intervention to decrease HIV-related risk behavior and trauma-related stress symptoms. Participants completed the Trauma History Questionnaire, the Impact of Events Scale-Revised, and the Stanford Acute Stress Reaction Questionnaire. Overall, 35.3% of the participants reported having experienced childhood sexual abuse. A total of 55.7% of the sample met diagnostic criteria for PTSD. The intensity of dissociative symptoms that participants endorsed was positively associated with experience of childhood sexual abuse (r = .20, p < .01). Dissociative symptoms were also positively associated with specific PTSD symptoms, notably hyperarousal (r = .69, p < .001). Hierarchical regression indicated that hyperarousal symptoms accounted for more of the variance in dissociation than childhood sexual abuse. These results suggest that childhood sexual abuse may be involved in the development of dissociative symptoms in the context of adulthood stress reactions. Furthermore, the pattern of the association between dissociation and PTSD is consistent with the possibility of a dissociative PTSD subtype among HIV-positive men.

Source imaging of P300 auditory evoked potentials and clinical correlations in patients with posttraumatic stress disorder

OBJECTIVE

Posttraumatic stress disorder (PTSD) is associated with abnormal information processing. The P300 component of event-related potentials (ERPs) is known to be a useful marker of information processing. The purposes of this study were to determine the P300 current source density in PTSD patients, and its relationship with symptom severity.

METHODS

ERPs were recorded in 30 PTSD patients and 33 healthy controls while participants were performing the auditory oddball task. We compared P300 current source density data--obtained by standardized low-resolution brain electromagnetic tomography (sLORETA)--between the two groups. The correlation between P300 current source density and clinical symptoms (as evaluated using the Korean version of the Structured Interview for PTSD--K-SIPS and Davidson Trauma Scale--K-DTS) was conducted.

RESULTS

In PTSD patients, the current source density of P300 is significantly reduced in the inferior frontal gyrus, precentral gyrus, insula, and anterior cingulate compared to healthy controls. Total K-DTS scores were correlated with the P300 current source density in the posterior cingulate gyrus. The K-SIP B items (re-experiencing) and K-SIB D items (increased arousal) were positively correlated with P300 current source densities in several brain regions located in the frontal, parietal, and temporal lobe (p<0.05). Conversely, the K-SIP C items (avoidance and numbing) were negatively correlated with P300 current source densities in the superior and middle frontal gyri in the frontal lobes (p<0.05).

CONCLUSION

The P300 current source densities reflected the pathophysiology of PTSD patients. PTSD symptoms were related to different neural activities, depending on their symptom characteristics.

Post-traumatic stress disorder vs traumatic brain injury

Post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI) often coexist because brain injuries are often sustained in traumatic experiences. This review outlines the significant overlap between PTSD and TBI by commencing with a critical outline of the overlapping symptoms and problems of differential diagnosis. The impact of TBI on PTSD is then described, with increasing evidence suggesting that mild TBI can increase risk for PTSD. Several explanations are offered for this enhanced risk. Recent evidence suggests that impairment secondary to mild TBI is largely attributable to stress reactions after TBI, which challenges the long-held belief that postconcussive symptoms are a function of neurological insult This recent evidence is pointing to new directions for treatment of postconcussive symptoms that acknowledge that treating stress factors following TBI may be the optimal means to manage the effects of many TBIs,

How understanding the neurobiology of complex post-traumatic stress disorder can inform clinical practice: a social cognitive and affective neuroscience approach

OBJECTIVE

In this review, we examine the relevance of the social cognitive and affective neuroscience (SCAN) paradigm for an understanding of the psychology and neurobiology of complex post-traumatic stress disorder (PTSD) and its effective treatment.

METHOD

The relevant literature pertaining to SCAN and PTSD was reviewed.

RESULTS

We suggest that SCAN offers a novel theoretical paradigm for understanding psychological trauma and its numerous clinical outcomes, most notably problems in emotional/self-awareness, emotion regulation, social emotional processing and self-referential processing. A core set of brain regions appear to mediate these collective psychological functions, most notably the cortical midline structures, the amygdala, the insula, posterior parietal cortex and temporal poles, suggesting that problems in one area (e.g. emotional awareness) may relate to difficulties in another (e.g. self-referential processing). We further propose, drawing on clinical research, that the experiences of individuals with PTSD related to chronic trauma often reflect impairments in multiple social cognitive and affective functions.

CONCLUSION

It is important that the assessment and treatment of individuals with complex PTSD not only addresses traumatic memories but also takes a SCAN-informed approach that focuses on the underlying deficits in emotional/self-awareness, emotion regulation, social emotional processing and self-referential processing.

Psychostimulant treatment of combat-related posttraumatic stress disorder

The objective of this paper is to describe three cases of combat-related posttraumatic stress disorder (PTSD), largely refractory to standard medication treatment who responded well to psychostimulant treatment. Symptoms of PTSD potentially result from chronic, stress-induced dopaminergic dysfunction in the prefrontal cortex/basal ganglia system. Psychostimulants, by their relative propensity to enhance dopamine (DA) activity within these brain regions, may have particular value in targeting this dysfunction. Evidence of dopaminergic dysfunction following chronic stress is reviewed and possible mechanism of action of psychostimulants is explored. Psychostimulants appeared to be well tolerated and beneficial in the treatment of the cases of combat-related PTSD reported. General applicability of the use of psychostimulants in combat- and non-combat-related PTSD awaits further study. The potential implications of these findings in further delineating pathophysiology and treatment in PTSD deserve further exploration.

Considering PTSD for DSM-5

This is a review of the relevant empirical literature concerning the DSM-IV-TR diagnostic criteria for PTSD. Most of this work has focused on Criteria A1 and A2, the two components of the A (Stressor) Criterion. With regard to A1, the review considers: (a) whether A1 is etiologically or temporally related to the PTSD symptoms; (b) whether it is possible to distinguish "traumatic" from "non-traumatic" stressors; and (c) whether A1 should be eliminated from DSM-5. Empirical literature regarding the utility of the A2 criterion indicates that there is little support for keeping the A2 criterion in DSM-5. The B (reexperiencing), C (avoidance/numbing) and D (hyperarousal) criteria are also reviewed. Confirmatory factor analyses suggest that the latent structure of PTSD appears to consist of four distinct symptom clusters rather than the three-cluster structure found in DSM-IV. It has also been shown that in addition to the fear-based symptoms emphasized in DSM-IV, traumatic exposure is also followed by dysphoric, anhedonic symptoms, aggressive/externalizing symptoms, guilt/shame symptoms, dissociative symptoms, and negative appraisals about oneself and the world. A new set of diagnostic criteria is proposed for DSM-5 that: (a) attempts to sharpen the A1 criterion; (b) eliminates the A2 criterion; (c) proposes four rather than three symptom clusters; and (d) expands the scope of the B-E criteria beyond a fear-based context. The final sections of this review consider: (a) partial/subsyndromal PTSD; (b) disorders of extreme stress not otherwise specified (DESNOS)/complex PTSD; (c) cross- cultural factors; (d) developmental factors; and (e) subtypes of PTSD.

Different white matter abnormalities between the first-episode, treatment-naive patients with posttraumatic stress disorder and generalized anxiety disorder without comorbid conditions

BACKGROUND

This study compared brain white matter integrity in two groups of patients with DSM-IV anxiety disorders.

METHOD

Seventeen patients with posttraumatic stress disorder (PTSD), 20 with generalized anxiety disorder (GAD), and 28 healthy controls were assessed on diffusion tensor imaging.

RESULTS

As compared to healthy controls, increased fractional anisotropy (FA) in left superior frontal gyrus in PTSD patients, and increased FA in right postcentral gyrus in GAD subjects were exhibited. Furthermore, patients with PTSD showed reduced FA in right anterior cingulate gyrus relative to GAD subjects. However, there was no significant correlation between the FA value of any altered region and the severity of PTSD or GAD.

LIMITATIONS

The sample studied can be considered small. Gender and educational level were not well-matched among the groups.

CONCLUSIONS

We tentatively speculate that abnormal white matter integrity of right anterior cingulate gyrus is an important neuroimaging marker of PTSD that distinguishes it from other anxiety disorders such as GAD.

Heart rate variability in response to affective scenes in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is characterized by psychophysiological abnormalities, such as an altered baseline heart rate and either hyper- or hyporeactivity to a wide range of stimuli, implying dysfunctional arousal regulation. Heart rate variability (HRV) has been established as an important marker of arousal regulatory ability. The aim of the present study was to examine HRV in PTSD under different affective conditions and to explore the role of potential moderating factors. To meet this purpose, videos of varying emotional valence were presented to trauma-exposed participants with PTSD (n=26), trauma-exposed participants without PTSD (n=26), as well as non-trauma-exposed controls (n=18) while HRV was recorded. The PTSD group showed lower HRV than non-trauma-exposed controls at baseline (corrected for age) and throughout different affective conditions implying decreased parasympathetic activity and an inflexible response regulation. There was a negative relationship between HRV and self-report of both depression and state dissociation.

Fear conditioning, synaptic plasticity and the amygdala: implications for posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is an anxiety disorder that can develop after a traumatic experience such as domestic violence, natural disasters or combat-related trauma. The cost of such disorders on society and the individual can be tremendous. In this article, we review how the neural circuitry implicated in PTSD in humans is related to the neural circuitry of fear. We then discuss how fear conditioning is a suitable model for studying the molecular mechanisms of the fear components that underlie PTSD, and the biology of fear conditioning with a particular focus on the brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB), GABAergic and glutamatergic ligand-receptor systems. We then summarize how such approaches might help to inform our understanding of PTSD and other stress-related disorders and provide insight to new pharmacological avenues of treatment of PTSD.

Neural mechanisms of impaired fear inhibition in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) can develop in some individuals who are exposed to an event that causes extreme fear, horror, or helplessness (APA, 1994). PTSD is a complex and heterogeneous disorder, which is often co-morbid with depression, substance abuse, and anxiety disorders such as panic or social phobia. Given this complexity, progress in the field can be greatly enhanced by focusing on phenotypes that are more proximal to the neurobiology of the disorder. Such neurobiological intermediate phenotypes can provide investigative tools to increase our understanding of the roots of the disorder and develop better prevention or intervention programs. In the present paper, we argue that the inhibition of fear responses is an intermediate phenotype that is related to both the neurocircuitry associated with the disorder, and is linked to its clinical symptoms. An advantage of focusing on fear inhibition is that the neurobiology of fear has been well investigated in animal models providing the necessary groundwork in understanding alterations. Furthermore, because many paradigms can be tested across species, fear inhibition is an ideal translational tool. Here we review both the behavioral tests and measures of fear inhibition and the related neurocircuitry in neuroimaging studies with both healthy and clinical samples.

Altered resting-state functional connectivity of thalamus in earthquake-induced posttraumatic stress disorder: a functional magnetic resonance imaging study

BACKGROUND

Thalamic dysfunction has been found in patients with posttraumatic stress disorder (PTSD), suggesting that the thalamus may be implicated in the etiology of PTSD. However, no studies have explored the functional connectivity between the thalamus and other brain regions during resting-state. The objective of the present study was to investigate the resting-state functional connectivity of the thalamus in recent onset medication-naive PTSD sufferers who went through an earthquake in the Sichuan province of China.

METHODS

Fifty-four participants with PTSD and seventy-two age and gender matched traumatized controls without PTSD recruited from the 2008 Sichuan earthquake were scanned by 3T functional magnetic resonance imaging (fMRI) in resting state. Region of interest (ROI)-based functional connectivity analysis was employed to identify the potential differences in the functional connectivity of the thalamus between the two groups.

RESULTS

In the PTSD group, the thalamus-ROIs showed decreased positive functional connectivity to particular brain regions including right medial frontal gyrus and left anterior cingulate cortex. Importantly, we also found increased positive functional connectivity of thalamus-ROIs with bilateral inferior frontal and left middle frontal gyri, left inferior parietal lobule as well as right precuneus in the PTSD participants when compared to traumatized controls without PTSD.

CONCLUSION

The results provide evidence that abnormal resting state functional connections linking the thalamus to cortical regions may be involved in the underlying pathology in PTSD.

Neuro-psychopharmacogenetics and Neurological Antecedents of Posttraumatic Stress Disorder: Unlocking the Mysteries of Resilience and Vulnerability

BACKGROUND AND HYPOTHESIS

Although the biological underpinnings of immediate and protracted trauma-related responses are extremely complex, 40 years of research on humans and other mammals have demonstrated that trauma (particularly trauma early in the life cycle) has long-term effects on neurochemical responses to stressful events. These effects include the magnitude of the catecholamine response and the duration and extent of the cortisol response. In addition, a number of other biological systems are involved, including mesolimbic brain structures and various neurotransmitters. An understanding of the many genetic and environmental interactions contributing to stress-related responses will provide a diagnostic and treatment map, which will illuminate the vulnerability and resilience of individuals to Posttraumatic Stress Disorder (PTSD).

PROPOSAL AND CONCLUSIONS

We propose that successful treatment of PTSD will involve preliminary genetic testing for specific polymorphisms. Early detection is especially important, because early treatment can improve outcome. When genetic testing reveals deficiencies, vulnerable individuals can be recommended for treatment with "body friendly" pharmacologic substances and/or nutrients. Results of our research suggest the following genes should be tested: serotoninergic, dopaminergic (DRD2, DAT, DBH), glucocorticoid, GABAergic (GABRB), apolipoprotein systems (APOE2), brain-derived neurotrophic factor, Monamine B, CNR1, Myo6, CRF-1 and CRF-2 receptors, and neuropeptide Y (NPY). Treatment in part should be developed that would up-regulate the expression of these genes to bring about a feeling of well being as well as a reduction in the frequency and intensity of the symptoms of PTSD.

Police officers under attack: resilience implications of an fMRI study

OBJECTIVE

Crime is now a top-priority public-health issue in many urban areas. Sao Paulo's state police force was the target of gunfire attack on an unprecedented scale. Several officers were killed or wounded, and many more were affected by psychological trauma. We investigated the brain activity underlying trauma, the coping effect of psychotherapy, and resilience in a highly homogenous sample that experienced the same traumatic event. The design applied was a between-group comparison of cerebral blood-oxygenation-level-dependent signals and symptom scores of police officers with and without partial Posttraumatic Stress Disorder (pPTSD).

METHOD

We used functional magnetic resonance imaging (fMRI) to investigate the retrieval of traumatic memories of 36 volunteers divided in three groups: (1) pPTSD policemen submitted to psychotherapy; (2) pPTSD policemen on the wait list; and (3) symptom-free (resilient) policemen. All participants were given a baseline fMRI scan and a follow-up scan some 40 days later. Not given psychotherapy, groups 2 and 3 were controls.

RESULTS

Group 1 showed 37% fewer PTSD symptoms post-psychotherapy and their scores and neural expressions were comparable to Group 3 resilient policemen. A marked increased in medial prefrontal cortex (mPFC) activity was concomitant with decreased amygdala activity during traumatic memory retrieval in both resilient and pPTSD participants (after psychotherapy) and these findings were associated with symptom attenuation.

CONCLUSIONS

Our results provide neurophysiological evidence of resilience in a high-risk group for PTSD. Psychotherapy may help to build narratives and resilient integrated translations of fragmented traumatic memories via mPFC, and thus weaken their sensory content while strengthening them cognitively.

Association between flashbacks and structural brain abnormalities in posttraumatic stress disorder

OBJECTIVE

Posttraumatic stress disorder (PTSD) is reliably associated with reduced brain volume relative to healthy controls, in areas similar to those found in depression. We investigated whether in a PTSD sample brain volumes in these areas were related to reporting specific symptoms of PTSD or to overall symptom severity.

METHOD

Structural MRI scans were obtained from 28 participants diagnosed with PTSD according to DSM-IV-TR. Participants reported the extent of individual PTSD symptoms using the Posttraumatic Diagnostic Scale. Voxel-based morphometry applying the Dartel algorithm implemented within SPM5 was used to identify volumetric changes, related to PTSD total, symptom cluster, and individual symptom scores.

RESULTS

Brain volume was unrelated to overall PTSD severity, but greater reexperiencing scores predicted reduced volumes in the middle temporal and inferior occipital cortices. Increased reports of flashbacks predicted reduced volume in the insula/parietal operculum and in the inferior temporal gyrus.

CONCLUSION

The data illustrate the value of analyses at the symptom level within a patient population to supplement group comparisons of patients and healthy controls. Areas identified were consistent with a neurobiological account of flashbacks implicating specific abnormalities in the ventral visual stream.

Acupuncture for posttraumatic stress disorder: conceptual, clinical, and biological data support further research

Posttraumatic stress disorder (PTSD) is common, debilitating, and has highly heterogeneous clinical and biological features. With the exception of one published preliminary clinical trial, rationale in support of the efficacy of acupuncture, a modality of Chinese medicine (CM), for PTSD has not been well described. This is a focused review of conceptual and clinical features of PTSD shared by modern western medicine (MWM) and CM, and of biological mechanisms of acupuncture that parallel known PTSD pathology. MWM and CM both recognize individual developmental variables and interactions between external conditions and internal responses in the genesis of PTSD. There is one published and one unpublished clinical trial that preliminarily support the efficacy of acupuncture for PTSD. Although there have been no mechanistic studies of acupuncture in human PTSD, extant research shows that acupuncture has biological effects that are relevant to PTSD pathology. Conceptual, clinical, and biological data support possible efficacy of acupuncture for PTSD. However, further definitive research about simultaneous clinical and biological effects is needed to support the use of acupuncture for PTSD in health care systems.

Change in Regional Cerebral Function in L'Aquila Earthquake Survivors with Post-Traumatic Stress Disorder: Preliminary Findings

Subjects with post-traumatic stress disorder (PTSD) present a diminished or blunted emotional response, sometimes called “emotional numbing” (EN), that constitutes one of the central symptoms in PTSD. Symptoms of EN include diminished interest in activities, feeling detached or estranged from others, and restricted range of affect (American Psychiatric Association, 2000). The present work studied the emotional components in individuals with PTSD with the principal aim of investigating subjects' functional alteration in the limbic regions, insula and frontal cortex during an emotional task compared with healthy subjects. Ten subjects with PTSD (survivors of the 6.3 magnitude earthquake of April 6, 2009 in L'Aquila) and ten healthy controls underwent fMRI. PTSD was diagnosed according to DSM-IV-R (APA 2000). All subjects underwent fMRI while viewing content-neutral and emotional stimuli. Data analysis revealed that PTSD subjects had significantly greater cerebral activation in particular in the right anterior insula and in bilateral inferior frontal gyrus. Our data suggest that there is a change in the activation of brain areas responsible for emotional processing in patients with PTSD and are consistent with previous findings demonstrating hyperactivation in frontolimbic structures during emotional tasks. Our study suggests that close personal experience may be critical in engaging the neural mechanisms underlying the emotional modulation of memory. Our findings provide evidence that significant alterations in brain function, similar in many ways to those observed in PTSD, can be seen shortly after major traumatic experiences, highlighting the need for early evaluation and intervention for trauma survivors.

Considering PTSD from the perspective of brain processes: a psychological construction approach

Posttraumatic stress disorder (PTSD) is a complex psychiatric disorder that involves symptoms from various domains that appear to be produced by the combination of several mechanisms. The authors contend that existing neural accounts fail to provide a viable model that explains the emergence and maintenance of PTSD and the associated heterogeneity in the expression of this disorder (cf. Garfinkel & Liberzon, 2009). They introduce a psychological construction approach as a novel framework to probe the brain basis of PTSD, where distributed networks within the human brain are thought to correspond to the basic psychological ingredients of the mind. The authors posit that it is the combination of these ingredients that produces the heterogeneous symptom clusters in PTSD. Their goal is show that a constructionist approach has significant heuristic value in understanding the emergence and maintenance of PTSD symptoms, and leads to different and perhaps more useful conjectures about the origins and maintenance of the syndrome than the traditional hyperreactive fear account.

From hysteria and shell shock to posttraumatic stress disorder: comments on psychoanalytic and neuropsychological approaches

In this paper, we look back at some of the earliest psychoanalytic approaches to trauma. The theoretical feasibility of reconciling psychoanalytic and neurobiological accounts of the effects of severe stress is examined. First, several epistemic considerations about the concepts of falsifiability and complexity in science are discussed with regard to neuroscience and psychoanalysis. We report the decisive discussions and descriptions of shell shock and hysteria that laid the foundation for the modern notions of dissociation and posttraumatic stress disorder (PTSD). We particularly underline the differences between "traumatic memory", which merely and unconsciously repeats the past, and "narrative memory", which narrates the past as past. Then, the construction of the modern concept of PTSD is described and the classification of conversion and dissociative disorders is questioned. In the next section, several recent neurobiological findings in patients with PTSD are reviewed. We place particular emphasis on cognitive impairment and cognitive bias relative to threatening stimuli, and on a general pattern of facilitated and heightened activation of the amygdala for threat-related stimuli, which are both recognized symptoms of PTSD. A possible meeting point between Cannon's and Freud's theoretical concepts is discussed in the frame of a deregulation of the stress system which helps not only to regulate homeostasis but also to adjust behaviour to external threats. We conclude that, although psychoanalysis and neuroscience may reciprocally complement and enlighten each other, their objects and methods, and thence their concepts, are fundamentally different.

Attention to novel and target stimuli in trauma survivors

Trauma and its consequences can have lasting biological and cognitive effects on those who experience them. This study investigated the extent to which trauma, posttraumatic stress disorder (PTSD), and dissociation influenced attention to basic auditory stimuli in a sample of military cadets. After filling out a series of psychometric questionnaires, 27 male military cadets varying in their trauma history participated in the "novelty" oddball task in which participants were asked to count high-pitched tones while ignoring other auditory stimuli. Electroencephalogram (EEG) was continually recorded in order to assess P300 responses, an event-related potential (ERP) associated with attention and memory processes. Trauma history only, and not dissociation or PTSD scores, predicted smaller P300 amplitudes to target tones. To distracting novel sounds, only trauma history and dissociation predicted unique variance in P300 amplitudes. The findings suggest that PTSD may not be central to the attentional disturbances found in traumatized samples, while trauma history and dissociation may play a more important role. Future studies investigating attentional processes post trauma should utilize dissociation scales and a non-trauma sample.

Switching between executive and default mode networks in posttraumatic stress disorder: alterations in functional connectivity

Working memory processing and resting-state connectivity in the default mode network are altered in patients with posttraumatic stress disorder (PTSD). Because the ability to effortlessly switch between concentration on a task and an idling state during rest is implicated in both these alterations, we undertook a functional magnetic resonance imaging study with a block design to analyze task-induced modulations in connectivity.

METHODS

We performed a working memory task and psychophysiologic interaction analyses with the posterior cingulate cortex and the medial prefrontal cortex as seed regions during fixation in 12 patients with severe, chronic PTSD and 12 healthy controls.

RESULTS

During the working memory task, the control group showed significantly stronger connectivity with areas implicated in the salience and executive networks, including the right inferior frontal gyrus and the right inferior parietal lobule. The PTSD group showed stronger connectivity with areas implicated in the default mode network, namely enhanced connectivity between the posterior cingulate cortex and the right superior frontal gyrus and between the medial prefrontal cortex and the left parahippocampal gyrus.

LIMITATIONS

Because we were studying alterations in patients with severe, chronic PTSD, we could not exclude patients taking medication. The small sample size may have limited the power of our analyses. To avoid multiple testing in a small sample, we only used 2 seed regions for our analyses.

CONCLUSION

The different patterns of connectivity imply significant group differences with task-induced switches (i.e., engaging and disengaging the default mode network and the central-executive network).

Abnormal grey matter in victims of rape with PTSD in Mainland China: a voxel-based morphometry study

Sui SG, Wu MX, King ME, Zhang Y, Ling L, Xu JM, Weng XC, Duan L, Shan BC, Li LJ. Abnormal grey matter in victims of rape with PTSD in Mainland China: a voxel-based morphometry study.

OBJECTIVE

This study examined changes in brain grey matter in victims of rape (VoR) with and without post-traumatic stress disorder (PTSD). Previous research has focused on PTSD caused by various traumatic events, such as war and disaster, among others. Although considerable research has focused on rape-related PTSD, limited studies have been carried out in the context of Mainland China.

METHODS

The study included 11 VoR with PTSD, 8 VoR without PTSD and 12 healthy comparison (HC) subjects. We used voxel-based morphometry to explore changes in brain grey-matter density (GMD) by applying statistical parametric mapping to high-resolution magnetic resonance images.

RESULTS

Compared with HC, VoR with PTSD showed significant GMD reductions in the bilateral medial frontal cortex, left middle frontal cortex, middle temporal gyrus and fusiform cortex and significant GMD increases in the right posterior cingulate cortex, postcentral cortex, bilateral precentral cortex and inferior parietal lobule. Compared to VoR without PTSD, VoR with PTSD showed significant GMD reductions in the right uncus, left middle temporal gyrus, and the fusiform cortex, and increases in the left precentral cortex, inferior parietal lobule and right post-central cortex.

CONCLUSION

The findings of abnormal GMD in VoR with PTSD support the hypothesis that PTSD is associated with widespread anatomical changes in the brain. The medial frontal cortex, precentral cortex, posterior cingulate cortex, post-central cortex and inferior parietal lobule may play important roles in the neuropathology of PTSD.

Emotion modulation in PTSD: Clinical and neurobiological evidence for a dissociative subtype

In this article, the authors present evidence regarding a dissociative subtype of PTSD, with clinical and neurobiological features that can be distinguished from nondissociative PTSD. The dissociative subtype is characterized by overmodulation of affect, while the more common undermodulated type involves the predominance of reexperiencing and hyperarousal symptoms. This article focuses on the neural manifestations of the dissociative subtype in PTSD and compares it to those underlying the reexperiencing/hyperaroused subtype. A model that includes these two types of emotion dysregulation in PTSD is described. In this model, reexperiencing/hyperarousal reactivity is viewed as a form of emotion dysregulation that involves emotional undermodulation, mediated by failure of prefrontal inhibition of limbic regions. In contrast, the dissociative subtype of PTSD is described as a form of emotion dysregulation that involves emotional overmodulation mediated by midline prefrontal inhibition of the same limbic regions. Both types of modulation are involved in a dynamic interplay and lead to alternating symptom profiles in PTSD. These findings have important implications for treatment of PTSD, including the need to assess patients with PTSD for dissociative symptoms and to incorporate the treatment of dissociative symptoms into stage-oriented trauma treatment.

Patterns of altered cortical perfusion and diminished subcortical integrity in posttraumatic stress disorder: an MRI study

Posttraumatic stress disorder (PTSD) accounts for a substantial proportion of casualties among surviving soldiers of the Iraq and Afghanistan wars. Currently, the assessment of PTSD is based exclusively on symptoms, making it difficult to obtain an accurate diagnosis. This study aimed to find potential imaging markers for PTSD using structural, perfusion, and diffusion magnetic resonance imaging (MRI) together. Seventeen male veterans with PTSD (45 ± 14 years old) and 15 age-matched male veterans without PTSD had measurements of regional cerebral blood flow (rCBF) using arterial spin labeling (ASL) perfusion MRI. A slightly larger group had also measurements of white matter integrity using diffusion tensor imaging (DTI) with computations of regional fractional anisotropy (FA). The same subjects also had structural MRI of the hippocampal subfields as reported recently (W. Zhen et al. Arch Gen Psych 2010;67(3):296-303). On ASL-MRI, subjects with PTSD had increased rCBF in primarily right parietal and superior temporal cortices. On DTI, subjects with PTSD had FA reduction in white matter regions of the prefrontal lobe, including areas near the anterior cingulate cortex and prefrontal cortex as well as in the posterior angular gyrus. In conclusion, PTSD is associated with a systematic pattern of physiological and structural abnormalities in predominantly frontal lobe and limbic brain regions. Structural, perfusion, and diffusion MRI together may provide a signature for a PTSD marker.

Elevated response of human amygdala to neutral stimuli in mild post traumatic stress disorder: neural correlates of generalized emotional response

Previous evidence from functional magnetic resonance imaging (fMRI) studies has shown that amygdala responses to emotionally neutral pictures are exaggerated at a group level in patients with severe post-traumatic stress disorder (PTSD) [Hendler T, Rotshtein P, Yeshurun Y, Weizmann T, Kahn I, Ben-Bashat D, Malach R, Bleich A (2003) Neuroimage 19(3):587-600]. The present fMRI study tested the hypothesis that amygdala responses are elevated not only in response to negative pictures but also to neutral pictures as a function of disease severity in patients with mild symptoms and in subjects who did not develop symptoms. To this end, fMRI scans were performed in 10 patients with mild PTSD and 10 healthy controls (both victims of a bank robbery), during the execution of a visuo-attentional task in which they were asked to observe emotionally negative or neutral pictures. Control subjects showed enhanced amygdala responses to emotionally negative stimuli compared to neutral stimuli. On the contrary, PTSD patients were characterized by high amygdala responses to both neutral and emotional pictures, with no statistically significant difference between the two classes of stimuli. In the entire group, we found correlations among the severity of the PTSD symptoms, task performance, and amygdala activation during the processing of neutral stimuli. Results of this study suggest that amygdala responses and the selectivity of the emotional response to neutral stimuli are elevated as a function of disease severity in PTSD patients with mild symptoms.

Women with a history of childhood maltreatment exhibit more activation in association areas following non-traumatic olfactory stimuli: a fMRI study

BACKGROUND

The aim of this study was investigating how women with a history of childhood maltreatment (CM) process non-threatening and non-trauma related olfactory stimuli. The focus on olfactory perception is based on the overlap of brain areas often proposed to be affected in CM patients and the projection areas of the olfactory system, including the amygdala, orbitofrontal cortex, insula and hippocampus.

METHODS

Twelve women with CM and 10 controls participated in the study. All participants were, or have been, patients in a psychosomatic clinic. Participants underwent a fMRI investigation during olfactory stimulation with a neutral (coffee) and a pleasant (peach) odor. Furthermore, odor threshold and odor identification (Sniffin' Sticks) were tested.

PRINCIPAL FINDINGS

Both groups showed normal activation in the olfactory projection areas. However, in the CM-group we found additionally enhanced activation in multiple, mainly neocortical, areas that are part of those involved in associative networks. These include the precentral frontal lobe, inferior and middle frontal structures, posterior parietal lobe, occipital lobe, and the posterior cingulate cortex.

CONCLUSIONS

The results indicate that in this group of patients, CM was associated with an altered processing of olfactory stimuli, but not development of a functional olfactory deficit. This complements other studies on CM insofar as we found the observed pattern of enhanced activation in associative and emotional regions even following non-traumatic olfactory cues.

Dissociation Following Traumatic Stress

We postulate that the cascade “Freeze-Flight-Fight-Fright-Flag-Faint” is a coherent sequence of six fear responses that escalate as a function of defense possibilities and proximity to danger during life-threat. The actual sequence of trauma-related response dispositions acted out in an extremely dangerous situation therefore depends on the appraisal of the threat by the organism in relation to her/his own power to act (e.g., age and gender) as well as the perceived characteristics of threat and perpetrator. These reaction patterns provide optimal adaption for particular stages of imminence. Subsequent to the traumatic threats, portions of the experience may be replayed. The actual individual cascade of defense stages a survivor has gone through during the traumatic event will repeat itself every time the fear network, which has evolved peritraumatically, is activated again (i.e., through internal or external triggers or, e.g., during exposure therapy).When a parasympathetically dominated ‘‘shut-down’’ was the prominent peri-traumatic response during the traumatic incident, comparable dissociative responses may dominate responding to subsequently experienced threat and may also reappear when the traumatic memory is reactivated. Repeated experience of traumatic stress forms a fear network that can become pathologically detached from contextual cues such as time and location of the danger, a condition which manifests itself as posttraumatic stress disorder (PTSD). Intrusions, for example, can therefore be understood as repetitive displays of fragments of the event, which would then, depending on the dominant physiological response during the threat, elicit a corresponding combination of hyperarousal and dissociation. We suggest that trauma treatment must therefore differentiate between patients on two dimensions: those with peritraumatic sympathetic activation versus those who went down the whole defense cascade, which leads to parasympathetic dominance during the trauma and a corresponding replay of physiological and dissociative responding, when reminded. The differential management of dissociative stages (“fright” and “faint”) has important treatment implications.