Science may be a step closer to understanding a question that is at once mundane and profound: why we scratch that itch.

Researchers in Shanghai published a study on Thursday identifying the part of the brain that could be responsible for inducing mice to scratch an itch. Dr. Sun Yangang and his team from the Chinese Academy of Sciences unveiled their research in the journal Neuron.

Scientists have made headway in recent years by identifying the neural chemicals and pathways responsible for itching, but our understanding of the mechanism behind the scratch reflex in response to our itches remains poor.

For those uninitiated in the science behind the sensation, Sun and his team at the CAS' Institute of Neuroscience identified a key pathway last year in processing an itch. When our skin is stimulated such as by a mosquito bite, cells release a chemical such as histamine, which in turn activate receptors that send a signal to the spinal cord. Neurons in the spine then route the signal to a part of the brain stem called the parabrachial nucleus (PBN).

Sun's most recent study reveals that another brain region called the periaqueductal gray (PAG) show increased activity in mice after itching was induced with injections of histamine or the antimalarial drug chloroquine.

The study emphasized that scratching could be provoked by stimulating certain PAG neurons without injections. Just as importantly, they could decrease scratching just by suppressing those neurons, bolstering the support for the importance of the region in processing an itch.

Though for many people, simply scratching an itch offers temporary relief, those who have long-term itching due to disease may increase the risk of infection if their scratches damage the skin. That's why knowing the mechanism behind the sensation and how we respond could take us one step closer to developing an effective treatment for itches that stem from different underlying conditions.

Chronic itching isn't just part of skin-related illnesses like chickenpox, but also a major symptom of multiple sclerosis and other autoimmune diseases. So far, there are a variety of remedies that include topical creams and antihistamines, but the silver bullet for treating a serious itch does not exist, yet.