An fMRI study of unconditioned responses in post-traumatic stress disorder

Background: Both fear and pain processing are altered in post-traumatic stress disorder (PTSD), as evidenced by functional neuroimaging studies showing increased amygdala responses to threats, and increased insula, putamen and caudate activity in response to heat pain. Using psychophysiology and functional magnetic resonance imaging, we studied conditioned and unconditioned autonomic and neuronal responses in subjects with PTSD versus trauma-exposed non-PTSD control (TENC) subjects. A design using an electric shock selected by subjects to be 'highly annoying but not painful' as an unconditioned stimulus (US) with partially reinforced cues allowed us to partly disentangle the expectancy- and prediction-error components from sensory components of the unconditioned response. Results: Whereas responses to the conditioned stimulus (CS) were similar in PTSD and TENC, the former displayed higher putamen, insula, caudate and amygdala responses to the US. Reactivity to the US in the anterior insula correlated with PTSD symptom severity. Functional connectivity analyses using the putamen as a seed region indicated that TENC subjects had increased amygdala-putamen connectivity during US delivery; this connection was disengaged in PTSD. Conclusions: Our results indicate that although neural processing of fear learning in people with PTSD seems to be comparable with controls, neural responses to unconditioned aversive stimuli in PTSD seem to be increased

An fMRI study of unconditioned responses in post-traumatic stress disorder

BACKGROUND: Both fear and pain processing are altered in post-traumatic stress disorder (PTSD), as evidenced by functional neuroimaging studies showing increased amygdala responses to threats, and increased insula, putamen and caudate activity in response to heat pain. Using psychophysiology and functional magnetic resonance imaging, we studied conditioned and unconditioned autonomic and neuronal responses in subjects with PTSD versus trauma-exposed non-PTSD control (TENC) subjects. A design using an electric shock selected by subjects to be 'highly annoying but not painful' as an unconditioned stimulus (US) with partially reinforced cues allowed us to partly disentangle the expectancy- and prediction-error components from sensory components of the unconditioned response. RESULTS: Whereas responses to the conditioned stimulus (CS) were similar in PTSD and TENC, the former displayed higher putamen, insula, caudate and amygdala responses to the US. Reactivity to the US in the anterior insula correlated with PTSD symptom severity. Functional connectivity analyses using the putamen as a seed region indicated that TENC subjects had increased amygdala-putamen connectivity during US delivery; this connection was disengaged in PTSD. CONCLUSIONS: Our results indicate that although neural processing of fear learning in people with PTSD seems to be comparable with controls, neural responses to unconditioned aversive stimuli in PTSD seem to be increased

Neurological Soft Signs in Individuals with Pathological Gambling

Increased neurological soft signs (NSSs) have been found in a number of neuropsychiatric syndromes, including chemical addiction. The present study examined NSSs related to perceptual-motor and visuospatial processing in a behavioral addiction viz., pathological gambling (PG). As compared to mentally healthy individuals, pathological gamblers displayed significantly poorer ability to copy two- and three-dimensional figures, to recognize objects against a background noise, and to orient in space on a road-map test. Results indicated that PG is associated with subtle cerebral cortical abnormalities. Further prospective clinical research is needed to address the NSSs' origin and chronology (e.g., predate or follow the development of PG) as well as their response to therapeutic interventions and/or their ability to predict such a response

Predicting post-trauma stress symptoms from pre-trauma psychophysiologic reactivity, personality traits and measures of psychopathology

Background: Most individuals exposed to a traumatic event do not develop post-traumatic stress disorder (PTSD), although many individuals may experience sub-clinical levels of post-traumatic stress symptoms (PTSS). There are notable individual differences in the presence and severity of PTSS among individuals who report seemingly comparable traumatic events. Individual differences in PTSS following exposure to traumatic events could be influenced by pre-trauma vulnerabilities for developing PTSS/PTSD. Methods Pre-trauma psychological, psychophysiological and personality variables were prospectively assessed for their predictive relationships with post-traumatic stress symptoms (PTSS). Police and firefighter trainees were tested at the start of their professional training (i.e., pre-trauma; n = 211) and again several months after exposure to a potentially traumatic event (i.e., post-trauma, n = 99). Pre-trauma assessments included diagnostic interviews, psychological and personality measures and two psychophysiological assessment procedures. The psychophysiological assessments measured psychophysiologic reactivity to loud tones and the acquisition and extinction of a conditioned fear response. Post-trauma assessment included a measure of psychophysiologic reactivity during recollection of the traumatic event using a script-driven imagery task. Results: Logistic stepwise regression identified the combination of lower IQ, higher depression score and poorer extinction of forehead (corrugator) electromyogram responses as pre-trauma predictors of higher PTSS. The combination of lower IQ and increased skin conductance (SC) reactivity to loud tones were identified as pre-trauma predictors of higher post-trauma psychophysiologic reactivity during recollection of the traumatic event. A univariate relationship was also observed between pre-trauma heart rate (HR) reactivity to fear cues during conditioning and post-trauma psychophysiologic reactivity. Conclusion: The current study contributes to a very limited literature reporting results from truly prospective examinations of pre-trauma physiologic, psychologic, and demographic predictors of PTSS. Findings that combinations of lower estimated IQ, greater depression symptoms, a larger differential corrugator EMG response during extinction and larger SC responses to loud tones significantly predicted higher PTSS suggests that the process(es) underlying these traits contribute to the pathogenesis of subjective and physiological PTSS. Due to the low levels of PTSS severity and relatively restricted ranges of outcome scores due to the healthy nature of the participants, results may underestimate actual predictive relationships

Screening for dissociative disorders in psychiatric out- and day care-patients

Dissociative disorders are frequent and clinically relevant conditions in psychiatric populations. Yet, their recognition in clinical practice is often poor. This study evaluated the performance of three well known and internationally used dissociation scales in screening for dissociative disorders. Consecutively treated out- and day care-patients (n = 160) from several psychiatric units in Switzerland completed the Dissociative Experiences Scale (DES), Somatoform Dissociation Questionnaire (SDQ-20), and Multidimensional Inventory for Dissociation (MID). The Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R) was then administered. Test performance of the scales was analyzed by receiver operating characteristic curves. The diagnostic accuracy, represented by the area under the curve, did not differ significantly between the three summary scales. Cut-off scores for detecting at least 80 % of any dissociative disorder and dissociative disorder-not-otherwise-specified/dissociative identity disorder, respectively, were 12 and 20 for the DES, 30 and 33 for the SDQ-20, and 28 and 28 for the MID summary scale. The diagnostic accuracy of the DES subscale ‘absorption’ and the MID subscale ‘somatic symptoms’ was equal or slightly lower than the corresponding summary scale. The DES, SDQ-20, and MID summary scales are suitable in screening for dissociative disorders in general psychiatric out- and day care-patients. Adequate cut-off scores in the German-adapted DES are lower than in non-German versions. Screening with the DES subscale ‘absorption’ and the MID subscale ‘somatic symptoms’ could be more efficient without the loss of diagnostic accuracy

Age-specific variation in apparent survival rates of male lesser-prairie-chickens

We used mark-recapture methods to estimate age-specific apparent survival rates for male Lesser Prairie-Chickens (Tympanuchus pallidicinctus), a gamebird of conservation concern. A total of 311 male prairie-chickens (135 yearlings, 176 adults) were captured and banded during a 5-year study in southwest Kansas. Time-since-marking models were used to estimate apparent survival after first capture (ϕ¹), apparent survival among returning birds (ϕ²⁺), and probability of capture (p) for yearling and adult prairie-chickens. Apparent survival is the product of true survival and site fidelity, and our model-averaged estimates of this parameter were ranked: yearlings after first capture (ϕ̂¹[subscript]yr = 0.60 ± 0.12) > adults after first capture (ϕ̂¹[subscript]ad = 0.44 ± 0.10) > returning birds (ϕ̂²⁺ = 0.36 ± 0.10). In contrast, movement data showed that site fidelity to communal display sites (or leks) increased with male age; yearlings returned to leks at lower rates (80%, n = 60) than adults (92%, n = 65). Thus, true survival rates of male Lesser Prairie-Chickens likely decline with increasing age, an unusual pattern found in few species of birds. We hypothesized that declines in survival as males' age may be a feature of promiscuous mating systems where competition for mating opportunities are intense. A review of annual survival rates for holarctic grouse did not support this idea; age-specific declines in male survival were not restricted to lek-mating species, and appear to be a general feature of most grouse populations.Keywords: age-specific demography, mark-recapture, grouse, Kansas, Tetraonidae, Tympanuchus pallidicinctu

Regional variation in mtDNA of the lesser prairie-chicken

Cumulative loss of habitat and long-term decline in the populations of the Lesser Prairie-Chicken (Tympanuchus pallidicinctus) have led to concerns for the species’ viability throughout its range in the southern Great Plains. For more efficient conservation past and present distributions of genetic variation need to be understood. We examined the distribution of mitochondrial DNA (mtDNA) variation in the Lesser Prairie-Chicken across Kansas, Colorado, Oklahoma, and New Mexico. Throughout the range we found little genetic differentiation except for the population in New Mexico, which was significantly different from most other populations. We did, however, find significant isolation by distance at the rangewide scale (r = 0.698). We found no relationship between haplotype phylogeny and geography, and our analyses provide evidence for a post-glacial population expansion within the species that is consistent with the idea that speciation within Tympanuchus is recent. Conservation actions that increase the likelihood of genetically viable populations in the future should be evaluated for implementation.This is the publisher’s final pdf. The article is copyrighted by Cooper Ornithological Society and published by Central Ornithology Publication Office. It can be found at: http://www.aoucospubs.org/loi/condKeywords: prairie grouse, Tympanuchus pallidicinctus, genetic diversity, Lesser Prairie-Chicken, DNA, mitochondrial DNAKeywords: prairie grouse, Tympanuchus pallidicinctus, genetic diversity, Lesser Prairie-Chicken, DNA, mitochondrial DN

Identification of Amazonian Trees with DNA Barcodes

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