Researchers from Harvard Medical School have found distinct features in the genes of the brain’s cerebral cortex. The gene expression found in this part of the brain shows the “downregulation of genes related to neural excitation and synaptic function.”

More specifically, this excitation of neurons directly refers to the neural activity in the brain. Neural activity is the processing and signal of neurons in the form of neurotransmitters and electrical currents.

Excessive neural activity causes muscle twitches or mood changes.

For the Harvard study, the scientists performed their experiments using worms.

The analysis of the genes was carried out by using mice and the cells of people who were over 100 years old when they died.

The various tests proved not only altered neural activity but also revealed clues on which molecular processes are involved.

Senior study author Bruce A. Yankner, a professor of genetics and neurology at Harvard Medical School, says “an intriguing aspect of our findings is that something as transient as the activity state of neural circuits could have such far-ranging consequences for physiology and life span.”

Scientists have known for some time that neural activity can affect a range of conditions, including epilepsy and dementia.

Despite all of the animal studies conducted to test this, the research has not extended to humans to observe this influence.

Current research shows signaling by the hormones insulin and insulin-like growth factor (IGF) are well-known molecular influencers of longevity.

The new findings reveal that neural excitation also influences longevity down this insulin and IGF signaling pathway through a transcription factor called REST.

The researchers found that REST also suppresses neural activity in animal models ranging from worms to mammals.

The transcription factor is found to suppress genes that have a direct impact on neural excitation.

These genes control ion channels, the receptors of chemical messengers, and components that makeup synapses, which are the structures that allow cells to send messages to each other.

The Harvard investigators ran tests in which they blocked REST in the animal models.

These tests resulted in higher neural activity and a shortened life span of the animals.

On the 100-year-old subjects, the tests of their brain tissue cells revealed significantly higher levels of REST in their nuclei compared with those whose life span had been 20–30 years shorter.

Lower neural activity is expressed through a group of proteins called forkhead transcription factors that influence longevity through the insulin and IGF signaling pathway in many organisms.

Prof. Yankner suggests that there are possible genetic and environmental factors behind the variation in neural activity in humans.

He and his team propose that the updated findings of REST should spark interest in developing drugs that target the protein. He warns, however, that their study did not clarify whether people’s personality, thinking, or behavior, can influence their life span.

IMAGE COURTESY OF HARVARDNEWS