Environment and experience influence defensive behaviors, but the neural circuits mediating such effects are not well understood. We describe a new experimental model in which either flight or freezing reactions can be elicited from mice by innately aversive ultrasound. Flight and freezing are negatively correlated, suggesting a competition between fear motor systems. An unfamiliar environment or a previous aversive event, moreover, can alter the balance between these behaviors. To identify potential circuits controlling this competition, global activity patterns in the whole brain were surveyed in an unbiased manner by c-fos in situ hybridization, using novel experimental and analytical methods. Mice predominantly displaying freezing behavior had preferential neural activity in the lateral septum ventral and several medial and periventricular hypothalamic nuclei, whereas mice predominantly displaying flight had more activity in cortical, amygdalar, and striatal motor areas, the dorsolateral posterior zone of the hypothalamus, and the vertical limb of the diagonal band. These complementary patterns of c-fos induction, taken together with known connections between these structures, suggest ways in which the brain may mediate the balance between these opponent defensive behaviors.

Background/Purpose:Orbital fractures are a common facial fracture managed by multiple surgical specialties. Methods: A retrospective review of the electronic medical records of patients (age, 18–85 years) presenting to Northwestern Memorial Hospital and Northwestern Medical Faculty Foundation in Chicago, IL, USA with International Classification of Diseases, Ninth Revision codes for facial fractures or CPT (Current Procedural Terminology) codes for orbital fracture repair.Results:A review of the electronic medical records identified 504 individual incidents of orbital fractures with available imaging for review. The most common location for an orbital fracture was a floor fracture (48.0%) followed by a medial wall fracture (25.2%). Left-sided orbital fractures were statistically significantly more common than right-sided orbital fractures (99% confidence interval). Orbital fractures were more prevalent in younger age groups. The mean patient age was 39.3 years. The most common cause of all orbital fractures was assault followed by falls. However, falls were the most common cause of orbital fractures in women and in patients aged 50 years and older. Evaluation by an ophthalmologist occurred in 62.8% of orbital fracture patients, and evaluation by a team comprising the facial trauma service (Otolaryngology, Plastic Surgery, and Oral and Maxillofacial Surgery) occurred in 81.9% of orbital fracture patients.Conclusion:Assault was the largest cause of all orbital fractures, and occurred most commonly in young males. Assaulted patients were more likely to have left-sided fractures compared to nonassaulted patients. In patients aged 50 years and older, falls were the most common cause of orbital fractures.

Chiang E, Strowbridge BW. Diversity of neural signals mediated by multiple, burst-firing mechanisms in rat olfactory tubercle neurons.

Cognitive theories regarding symptom formation suggest that environmental factors such as warnings of impending pain and earlier experiences with pain can lead to a cognitive schema in which pain is selectively monitored. This study evaluated the role of prior experience with pain in the development of expectancy induced somatoform pain. Subjects from two experimental groups were connected to a sham stimulator and told to expect a headache. One of these groups, the physical stimulation first group, was exposed to pain induction by ice water and by pressure prior to the sham stimulation. A second group, the sham stimulation first group, received the sham stimulation followed by the cold water and pressure pain induction techniques. Subjects in the physical stimulation first group showed significant increases in their pain reports as settings on the sham stimulator were increased. Significant increases were not noted in the sham stimulation first group. The two groups did not differ in the number of subjects reporting pain or the mean maximal pain reported during the sham stimulation. Duration of cold water tolerance and the time until the analgesic threshold level for cold water were significantly shorter in subjects who had the sham stimulation first. This study suggests that prior pain can influence the reactivity to external suggestion for pain but does not increase the frequency of pain reports. It does suggest that the selective monitoring induced during the sham stimulation may influence later pain behaviours as was seen during the cold water tolerance testing.

The authors describe 2 patients who presented with orbital findings and later developed vesicular lesions that were positive for varicella zoster virus and consistent with Herpes Zoster ophthalmicus. One case is the first to involve dacryoadenitis and orbital myositis preceding disseminated Herpes Zoster. In the other case, a patient developed zoster orbital syndrome leading to elevated intraocular pressure, loss of vision, and afferent pupillary defect. Canthotomy and cantholysis were required to restore vision. In both cases, the orbital syndrome developed prior to the vesicular rash. These cases highlight the need to consider Herpes Zoster ophthalmicus in patients with orbital syndrome not responding to conventional treatment.