Mental function and health are critical to overall well-being. In a study done from 2004 to 2008, it was established that American adults experience about four mentally unhealthy days each month. This includes feeling stressed out or even having a mental disorder worsen. The brain's proper function relies on a network of events to occur. Until now, researchers could not pinpoint which events and molecules are most important to adequate brain function.

A new study performed at the Yale University School of Medicine set out to find receptors and molecules critical for mental health and brain function. They reasoned that information in the conscious mind is processed in the brain's prefrontal cortex. Looking there, they established that brain function was reliant on the neurotransmitter, acetylcholine, (ACh) and its receptor, the nicotinic alpha-7 receptor (α7-nAChR).

Acetylcholine is an important neurotransmitter in all brains. It plays a vital role in attention and memory as well as wakefulness and arousal. This neurotransmitter is the reason we can react in certain situations and process complex information as well as remember all of it.

Receptors are key to neurotransmitter functions. The receptors in the brain are key because they receive information from other brain cells or neurons. The brain is a network of these neurons, all communicating with each other about thoughts, memories, reactions, and similar information. It has long been established that neurotransmitters need receptors in order to function in the brain.

It has also been established that hereditary mental health disorders, like schizophrenia, are rooted in malfunctioning receptors. A neurotransmitter may act normally in a schizophrenic's brain, but its receptor, used to receive the message the neurotransmitter is sending, is faulty and so the brain fails to react, compromising mental health.

This study focused on the ways in which the receptor for ACh as well as its locations within the brain can alter the way the brain communicates with itself to create brain functions, like thought-processing and memory.

In the study, researchers found that the α7-nAChR receptors were only found on brain cells that could receive messages from others. This is ideal, as receiving messages is the primary function of a receptor. If located only on cells receiving messages, then there is little room for inappropriate functions.

Similarly, when monkey's brains were given a drug that would stimulate the α7-nAChR receptor, without altering any of their other behaviors, in the effort to make them remember something over a period of time, those receiving stimulation were more likely to remember the information. This is notable, as a drug, similar to acetylcholine, was put into their brains, and the result was similar to having seen and recalled information about a location of a reward. This indicates that the receptors are certainly stimulated during times of cognition as well as recall.

Finally, when the receptors were blocked, there were little to no reactions in terms of brain stimulation. This is important to note, because if the receptor was unnecessary to cognitive function, the studied brains may have still functioned. But because they did not, the receptor and ACh to stimulate it are very important to brain function.

How does this alter therapy for those with mental disorders? It could greatly improve it. The study identifies the cellular basis for these behavioral actions. Now that it has been established that this receptor and its stimulator are key to cognitive function, therapies can act on the receptor to either stimulate it or improve its ability to be stimulated by ACh. Stimulation of receptors in the brain can be dangerous, as it can lead to addiction, so more work will be done to establish a safe dosage of receptor activator that does not cause addiction.

Source: Yang Y, Paspalas CD, Jin LE, Picciotto MR, Arnsten AFT, Wang M. Nicotinic α7 receptors enhance NMDA cognitive circuits in dorsolateral prefrontal cortex. Proceedings of the National Academy of Sciences. 2013.

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