Exploratory rearing is governed by hypothalamic MCH neurons according to locus coeruleus.

Abstract

Information seeking, such as standing on tiptoes to look around in humans, is observed across animals and helps survival. Its rodent analog - unsupported rearing on hind legs - was a classic model in deciphering neural signals of cognition, and is of intense renewed interest in preclinical modeling of neuropsychiatric states. Neural signals and circuits controlling this dedicated decision to seek information remain largely unknown. While studying sub-second timing of spontaneous behavioral acts and activity of MCH neurons (MNs) in behaving male and female mice, we observed large MN activity spikes that aligned to unsupported rears. Complementary causal, loss and gain of function, analyses revealed specific control of rear frequency and duration by MNs and MCHR1 receptors. Activity in a key stress center of the brain - the locus coeruleus noradrenaline cells - rapidly inhibited MNs, and required functional MCH receptors for its endogenous modulation of rearing. By defining a neural module that both tracks and controls rearing, these findings may facilitate further insights into biology of information seeking.Significance Statement Animals, including humans, use movement to interact with their environment - to reach specific targets or gain information, as when standing tall and looking around. Information-seeking is a fundamental behavior related to cognition and neuropsychiatric states. However, the neural circuits underlying it are still unclear. We show that hypothalamic neurons make melanin-concentrating hormone ("MN") are active during a well-known rodent analog of information-seeking - rearing on hind limbs - and contribute to driving these acts of rearing. We also find that locus coeruleus noradrenergic neurons, known for mediating stress responses, inhibit MNs, thus providing a neural link between stress and information-seeking. These results identify a neural substrate of information-seeking, and provide insights into how the brain toggles between conflicting, survival-critical priorities.