A new study in mice has shown that a previously developed male hormonal (testosterone) oral contraceptive method is unable to stop the production and / or the release of sperm.  

A group of researchers have erased memories in rats, profoundly altering the animals' reaction to past events. Then they put them back.

The study is the first to show the ability to selectively remove a memory and predictably reactivate it by stimulating nerves in the brain at frequencies that are known to weaken and strengthen the connections between nerve cells - synapses.

The scientists optically stimulated a group of nerves in a rat's brain that had been genetically modified to make them sensitive to light, and simultaneously delivered an electrical shock to the animal's foot. The rats soon learned to associate the optical nerve stimulation with pain and displayed fear behaviors when these nerves were stimulated.

New research reveals that bilingualism has a positive effect on cognition later in life. Findings published in Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society, show that individuals who speak two or more languages, even those who acquired the second language in adulthood, may slow down cognitive decline from aging.

Like blonde hair? You can thank the Kit ligand gene.

A single-letter change in the genetic code is enough to generate blond hair in humans, according to a new analysis by Howard Hughes Medical Institute scientists which has pinpointed that change, common in the genomes of Northern Europeans.

A handful of genes likely determine hair color in humans and the precise molecular basis of the trait remains poorly understood, and discovery of the genetic hair-color switch didn't begin with a deep curiosity about golden locks. It began with fish.

Twenty years after the hormone leptin was found to regulate metabolism, appetite, and weight through brain cells called neurons, a new study in Nature Neuroscience says that the hormone also acts on other types of cells to control appetite.

Leptin, a naturally occurring hormone, is known for its hunger-blocking effect on the hypothalamus, a region in the brain. Food intake is influenced by signals that travel from the body to the brain. Leptin is one of the molecules that signal the brain to modulate food intake. It is produced in fat cells and informs the brain of the metabolic state. If animals are missing leptin, or the leptin receptor, they eat too much and become severely obese.

A UCLA research team has discovered a new hormone called erythroferrone, which regulates the iron supply needed for red blood-cell production.

Iron is an essential functional component of hemoglobin, the molecule that transports oxygen throughout the body. Using a mouse model, researchers found that erythroferrone is made by red blood-cell progenitors in the bone marrow in order to match iron supply with the demands of red blood-cell production. Erythroferrone is greatly increased when red blood-cell production is stimulated, such as after bleeding or in response to anemia.