A review of hippocampal activation in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is often characterized by deficits in memory encoding and retrieval and aberrant fear and extinction learning. The hippocampus plays a critical role in memory and contextual processing and has been implicated in intrinsic functional connectivity networks involved in self-referential thought and memory-related processes. This review focuses on hippocampal activation findings during memory and fear and extinction learning tasks, as well as resting state hippocampal connectivity in individuals with PTSD. A preponderance of functional neuroimaging studies to date, using memory, fear learning, and extinction tasks, report decreased or “controls comparable” hippocampal activation in individuals with PTSD, which is usually associated with poorer performance on the task imaged. Existing evidence thus raises the possibility that greater hippocampal recruitment in PTSD participants may be required for similar performance levels. Studies of resting state functional connectivity in PTSD predominantly report reduced within-network connectivity in the default mode network (DMN), as well as greater coupling between the DMN and salience network (SN) via the hippocampus. Together, these findings suggest that deficient hippocampal activation in PTSD may be associated with poorer performance during memory, extinction recall, and fear renewal tasks. Furthermore, studies of resting state connectivity implicate the hippocampus in decreased within-network DMN connectivity and greater coupling with SN regions characteristic of PTSD.     

Radiological analysis of hand and foot injuries after small aircraft crashes

Medico-legal investigation of fatal aviation accidents should contribute to the reconstruction of the accident in addition to providing the usual information about cause and manner of death. In cases with more than one fatality, the question of who was flying the plane at the time of the crash may need to be answered. In such cases the identification of “control injuries” plays an important role. This study aims to investigate whether specific patterns of skeletal hand and foot injuries could assist in the identification of the pilot. The analysis of radiological investigations of hands and feet of 27 fatalities from 18 accidents showed that foot injuries are more frequent than hand injuries in pilots and passengers, dislocations of feet were more frequent in passengers, and right-sided injuries were more frequent in pilots. Injuries of the distal parts of the hand were slightly more frequent in the pilot group. The limited numbers in the study do not allow definitive conclusions and further investigations are needed. However, the study yields interesting results and shows that radiological examination should be included in the medico-legal air crash investigation.     

Systemic lupus erythematosus presenting as a non-o:1 vibrio cholerae abscess

The usual presentations and manifestations of systemic lupus erythematosus (SLE) are well known. We describe a patient with SLE that was discovered in the course of evaluation of an abscess, found to be associated with non-O:1 Vibrio cholerae.