Memory recall involves a transient break in excitatory-inhibitory balance

The brain has a remarkable capacity to acquire and store memories that can later be selectively recalled. These processes are supported by the hippocampus which is thought to index memory recall by reinstating information stored across distributed neocortical circuits. However, the mechanism that supports this interaction remains unclear. Here, in humans, we show that recall of a visual cue from a paired associate is accompanied by a transient increase in the ratio between glutamate and GABA in visual cortex. Moreover, these excitatory-inhibitory fluctuations are predicted by activity in the hippocampus. These data suggest the hippocampus gates memory recall by indexing information stored across neocortical circuits using a disinhibitory mechanism.

Orexin neuron activity in mating mice - a pilot study

Mating behaviours affect hypothalamic orexin/hypocretin neurons and vice versa. However, activity of orexin neurons has not been recorded during mating before. We report an anecdotal dataset of freely-moving miniature microscope recordings of orexin neuron activity during mating behaviours, as well as an oral sexual encounter previously undocumented in mice. Across the orexin neuron population in the male, firing rates were maximally diverse during ejaculation, similarly diverse though weaker during intromission, and inverse to this during anterior thrusting. In the female mouse, orexin neurons tended to decrease firing during intromission after a transient increase. We provide this brief dataset for re-use, to enable further studies of these rare behaviours with challenging surgical preparations.

The miR-424/503 cluster modulates Wnt/β-catenin signaling in the mammary epithelium by regulating the expression of the LRP6 co-receptor

During the female lifetime, the enlargement of the epithelial compartment dictated by the ovarian cycles is supported by a transient increase in the MaSC population. Notably, activation of Wnt/β-catenin signaling is an important trigger for MaSC expansion. Here, we report that the miR-424/503 cluster is a novel modulator of canonical Wnt-signaling in the mammary epithelium that exerts its function by targeting the LRP6 co-receptor. Additionally, we show that the loss of this microRNA cluster is associated with breast cancers possessing high levels of Wnt/β-catenin signaling.