Neural correlates of associative learning and memory in veterans with posttraumatic stress disorder

Impaired attention and memory are symptoms frequently associated with posttraumatic stress disorder (PTSD). Although patients with PTSD frequently report memory difficulties and empirical research provides support for a memory deficit in PTSD, as of yet, no fMRI study has adequately investigated the neural correlates of learning and memory of neutral (i.e. not trauma related) material in patients with PTSD compared to controls. Twelve male veterans with PTSD, and twelve male veterans without PTSD, were recruited, and matched for age, region and year of deployment. Encoding and retrieval of 12 word-pair associates was assessed during fMRI in both experimental groups. Compared to controls veterans with PTSD revealed underactivation of the frontal cortex, and overactivation of the temporal cortex during the encoding phase. Retrieval of the paired associates resulted in underactivation of right frontal cortex, bilateral middle temporal gyri, and the left posterior hippocampus/parahippocampal gyrus in patients with PTSD. Deficits in memory performance in PTSD appear to be related to altered activity in fronto-temporal areas during both the encoding and retrieval phase of memory processing.     

Hostility is related to clusters of T-cell cytokines and chemokines in healthy men

Hostility is a risk factor for adverse health outcomes as diverse as cardiovascular disease and post-traumatic stress disorder (PTSD). Cytokines have been suggested to mediate this relationship. We investigated whether in healthy men a relation existed between hostility and T-cell mitogen-induced cytokines and chemokines. Male Dutch military personnel (n=304) were included before deployment. Eleven cytokines and chemokines were measured in supernatants of T-cell mitogen-stimulated whole blood cultures by multiplex immunoassay. Factor analysis was used to identify clusters of cytokines and chemokines. In a regression analysis hostility was related to the cytokine/chemokine clusters, and the potential risk factors age, BMI, smoking, drinking, previous deployment, early life trauma and depression. Explorative factor analysis showed four functional clusters; a pro-inflammatory factor (IL-2, TNFalpha, IFNgamma), an anti-inflammatory factor (IL-4, IL-5, IL-10), IL-6/chemokine factor (IL-6, MCP-1, RANTES, IP-10), and MIF. Hostility was significantly related to decreased IL-6/chemokine secretion and increased pro- and anti-inflammatory cytokines. There was an inverse relation between age and hostility scores. Early life trauma and depression were positively and independently related to hostility as well. This study represents a novel way of investigating the relation between cytokines and psychological characteristics. Cytokines/chemokines clustered into functional factors, which were related to hostility in healthy males. Moreover this relation appeared to be independent of reported depression and early trauma.     

Deep white matter infarction: correlation of MR imaging and histopathologic findings

Focal and confluent areas of periventricular hyperintensity have been reported on magnetic resonance (MR) images in 30% of patients over 60 years of age. In order to better understand the pathologic basis of these lesions, the authors studied 14 formalin-fixed brains with MR imaging. Multiple focal areas of hyperintensity were identified in the periventricular white matter in three of the 14 brains studied (21%). Subsequent gross and microscopic pathologic examination of both hyperintense and normal-intensity areas was performed on 87 tissue sections. The larger lesions were characterized centrally by necrosis, axonal loss, and demyelination and therefore represent true infarcts. Reactive astrocytes oriented along the degenerated axons were identified at distances of up to several centimeters from the central infarct. This is called isomorphic gliosis and is associated with increased intensity on T2-weighted images that increases the apparent size of the central lesion.