Stress-induced Fos-like Immunoreactivity in the Pons and the Medulla Oblongata of Rats

Immunoreactivity of the immediate early gene c-fos was used to investigate changes in the activity of brainstem neurons in response to acute stressors like immobilization, formalin-induced pain, cold exposure, hemorrhage and insulin-induced hypoglycemia. Different stressors induced Fos-like immunoreactivity in different pontine and medullary neurons. A single, 3 hour immobilization was found to be a very strong stimulus that activated brainstem catecholaminergic (tyrosine hydroxylase-immunopositive) neurons and cells in the raphe and certain pontine tegmental nuclei, as well as in the reticular formation. Pain, induced by a subcutaneous injection of formalin was also effective on catecholamine-synthesizing neurons and on others cells in the nucleus of the solitary tract. Cold exposure activated cells mainly in the sensory spinal trigeminal and parabrachial nuclei and in the so-called "pontine thermoregulatory area". Moderate Fos-like immunoreactivity was induced by a hypotonic (25%) hemorrhage in medullary catecholaminergic neurons, the nucleus of the solitary tract and the Barrington nucleus. Among stressful stimuli used, insulin-induced hypoglycemia elicited the smallest Fos activation in the lower brainstem. The present observations indicate that different stressors may use different neuronal pathways in the central organization of the stress response.     

Essential neuronal pathways for reflex and conditioned response initiation in an intracerebellar stimulation paradigm and the impact of unconditioned stimulus preexposure on learning rate

It has been demonstrated previously that pairing of tone CS and intracerebellar stimulation of lobule HVI white matter as the US produces conditioning that is robust and in many ways similar to that obtained with an airpuff US. The first study in this report addressed the effect of interpositus lesions on conditioned performance in rabbits trained with white matter stimulation as the US. It was found that interpositus lesions effectively eliminated the CR irrespective of the behavioral response measured. In addition, it was shown that the interpositus lesions also abolished the UR, providing strong evidence that the effects of the electrical stimulation were confined to the cerebellum and did not require the activation of brainstem structures. The second experiment examined performance on US-alone trials of varying durations. Response initiation within 100 ms of the US onset, regardless of US duration, indicated that reflex generation could not be due to rebound excitation of the interpositus following termination of Purkinje cell inhibition of that structure but instead likely reflects orthodromic activation of interpositus neurons via climbing fiber and/or mossy fiber collaterals. The impact of US preexposure on associative conditioning in this paradigm was also determined. Animals which received only 108 US-alone trials were massively impaired during subsequent training compared to rabbits that received fewer than 12 US-alone trials.     

The combined influence of hardiness and cohesion on mental health in a military peacekeeping mission: A prospective study

A large number of studies have shown that hardiness and cohesion are associated with mental health in a military context. However, most of them are presented without controlling for baseline mental health symptoms, which is their most significant source of error. The present study investigates the combined effect of hardiness and cohesion in a prospective design, controlling for baseline levels of symptoms among Norwegian personnel serving in a peacekeeping operation in Kosovo. Multivariate regression analyses were performed in which self‐reported mental health complaints were regressed on our explanatory variables. Our findings suggest that both cohesion and hardiness contributed to increased stress resiliency, as measured by a lower level of reported mental health complaints. Our baseline measure of mental health accounted for a larger proportion of the variance than our other predictors. A significant interaction between cohesion and hardiness suggested a combined effect, over and above the individual contributions of the predictors. For individuals who scored high on hardiness, cohesion levels did not influence levels of mental health complaints. Individuals who scored low on hardiness, on the other hand, reported lower levels of mental health complaints when cohesion levels were high.     

The effect of hardiness on PTSD symptoms: A prospective mediational approach

Psychological hardiness has been associated with lower PTSD in military personnel, but the processes of action remain unclear. This study uses a prospective design to examine whether hardiness has an indirect effect on PTSD symptoms through avoidance coping. Our sample included 163 Norwegian military personnel who served in international operations between 2009 and 2010. Regression analyses were performed to estimate the coefficients in a simple mediation model, with baseline PTSD symptoms, combat exposure, and deprivation of basic needs entered as control variables. The results showed that the effect of hardiness on PTSD symptoms worked through reducing the use of avoidance coping. It was concluded that an avoidant-focused coping style acts as a vulnerability factor for PTSD symptoms, whereas hardiness acts as a resilience factor against symptoms development.     

Suicide in Denmark: A Statistical Review for the Past 150 Years

ABSTRACT: This paper presents a survey of suicide in Denmark from the time when statistics were first kept 100 years ago, up to the present. The remarkable high suicide rate at the start is discussed. The belief that suicide rate is influenced by several factors outside the individual, factors which to some extent can be influenced, is supported by the great variability of the suicide index during the last 100–150 years, being 29.9 in 1861, 12.8 in 1918 and 26 in 1976. The distribution according to sex and age today compared to 100 years ago suggests that the present social-political arrangements in Denmark have helped many elements of the population, especially the youngest and the eldest, and especially the men. However, among women 35 to 70 years old and especially those between 45 and 55 the suicide rate has increased. One possible explanation is today's greater number of divorces with all the troubles that follow. Finally, the changing of suicide methods is discussed.     

Suicide among Attempted Suicides

ABSTRACT: A 10-year follow-up is presented of 484 patients who made serious suicide attempts. Of this group 23% had died, 9% from natural causes, 3% from accidents or from uncertain causes, and 11% from suicide. Suicide frequency is highest in the period immediately after the suicide attempt. Especially interesting is the distribution according to sex. During the first 5 years there is a preponderance of male suicides (which is in agreement with the findings of other investigators), but after 10 years this difference in sex disappears. Suicides are found especially among men from 50 to 60 years of age, disabled pensioners, and persons who have attempted suicide several times, and to a lesser degree among persons living alone and criminals.