Neuronal activation in the paraventricular thalamus and lateral habenula during activity-based anorexia in mice

Self-starvation in anorexia nervosa patients ultimately progresses into a state of energy deficit and the body responds with homeostatic changes giving rise to many of the core symptoms. To accelerate progress towards effective therapies, we need to better understand the neurobiological underpinnings of this disease. Hence, we sought to identify brain regions of potential importance for anorexia nervosa by exploring neuronal activity in the activity-based anorexia (ABA) mouse model using Fos-TRAP2 technique. Given the function of many nuclei in the dorsal thalamus that centre around the integration of internal stimuli, such as metabolic state, with appropriate behavioural responses, activation of populations in the dorsal thalamus was the main focus. Substantial neuronal activation was found in several dorsal thalamic nuclei of ABA mice. In particular, ABA considerably increased neuronal activity in the paraventricular thalamus (PVT) and the lateral habenula (LHb). In addition, immunohistochemistry revealed that a significant proportion of the activated neurons in PVT and LHb were calretinin neurons, implicated in starvation-induced arousal. These findings position the dorsal thalamus as a region involved in anorexia-induced neuronal activities and as a potential site to further examine in the relation to anorexia nervosa.