Why do mice squeak? Toward a better understanding of defensive vocalization.

Although mice mostly communicate in the ultrasonic range, they also emit audible calls. We demonstrate that mice selectively bred for high anxiety-related behavior (HAB) have a high disposition for emitting sonic calls when caught by the tail. The vocalization was unrelated to pain but sensitive to anxiolytics.

Mn dynamics in manganese-enhanced MRI (MEMRI): Ca1.2 channel-mediated uptake and preferential accumulation in projection terminals.

Manganese-enhanced magnetic resonance imaging (MEMRI) exploits the biophysical similarity of Ca and Mn to map the brain's activity in vivo. However, to what extent different Ca channels contribute to the enhanced signal that MEMRI provides and how Mn dynamics influence Mn brain accumulation after systemic administration of MnCl are not yet fully understood. Here, we demonstrate that mice lacking the L-type Ca channel 1.

Biomarkers in posttraumatic stress disorder: overview and implications for future research.

PTSD can develop in the aftermath of traumatic incidents like combat, sexual abuse, or life threatening accidents. Unfortunately, there are still no biomarkers for this debilitating anxiety disorder in clinical use. Anyhow, there are numerous studies describing potential PTSD biomarkers, some of which might progress to the point of practical use in the future.

Hippocampus-dependent place learning enables spatial flexibility in C57BL6/N mice.

Spatial navigation is a fundamental capability necessary in everyday life to locate food, social partners, and shelter. It results from two very different strategies: (1) place learning which enables for flexible way finding and (2) response learning that leads to a more rigid "route following." Despite the importance of knockout techniques that are only available in mice, little is known about mice' flexibility in spatial navigation tasks.

Increased stress reactivity is associated with reduced hippocampal activity and neuronal integrity along with changes in energy metabolism.

Patients suffering from major depression have repeatedly been reported to have dysregulations in hypothalamus-pituitary-adrenal (HPA) axis activity along with deficits in cognitive processes related to hippocampal and prefrontal cortex (PFC) malfunction. Here, we utilized three mouse lines selectively bred for high (HR), intermediate, or low (LR) stress reactivity, determined by the corticosterone response to a psychological stressor, probing the behavioral and functional consequences of increased vs. decreased HPA axis reactivity on the hippocampus and PFC.

Reduced hippocampus volume in the mouse model of Posttraumatic Stress Disorder.

Some, but not all studies in patients with posttraumatic stress disorder (PTSD), report reduced hippocampus (HPC) volume. In particular it is unclear, whether smaller hippocampal volume represents a susceptibility factor for PTSD rather than a consequence of the trauma. To gain insight into the relationship of brain morphology and trauma exposure, we investigated volumetric and molecular changes of the HPC in a mouse model of PTSD by means of in vivo Manganese Enhanced Magnetic Resonance Imaging (MEMRI) and ex vivo ultramicroscopic measurements.

Fractionated manganese injections: effects on MRI contrast enhancement and physiological measures in C57BL/6 mice.

Manganese-enhanced MRI (MEMRI) is an increasingly used imaging method in animal research, which enables improved T(1)-weighted tissue contrast. Furthermore accumulation of manganese in activated neurons allows visualization of neuronal activity. However, at higher concentrations manganese (Mn2+) exhibits toxic side effects that interfere with the animals' behaviour and well-being.

Hippocampal N-acetylaspartate levels before trauma predict the development of long-lasting posttraumatic stress disorder-like symptoms in mice.

Background: Only a certain proportion of individuals develop posttraumatic stress disorder (PTSD) in the aftermath of a trauma. Biomarkers of individual susceptibility are not yet known but would enable selected primary and secondary prevention of PTSD.

Methods: Hippocampal N-acetylaspartate (NAA) levels were assessed by proton magnetic resonance spectroscopy ((1)H-MRS) in C57BL/6N mice prior to the perception of a 1.