As we age, everyone notices that movements become less smooth and maintaining balance becomes more difficult. For a long time, it was believed that this was simply an inevitable part of the body's aging process. However, scientists from McGill University (Canada) have managed to find a specific biological cause for these changes. Their recently published research indicates that the key to losing coordination lies in specific neurons in the cerebellum.

The key role of Purkinje cells

The focus of the researchers was on Purkinje cells — a unique type of neuron located in the cerebellum. This area of the brain is responsible for the fine-tuning of movements, balance, and their precision. Purkinje cells perform a complex task: they receive sensory information from the body and generate electrical impulses that regulate the rhythm and smoothness of our actions.

Unlike many other nerve cells, they are capable of generating their own electrical signals. It is this ability, as Canadian scientists have found, that critically declines with age, leading to visible symptoms of aging: slowed walking, unsteadiness, and impaired coordination.

Experiments: from young mice to old ones

To prove their theory, a team led by graduate student Evyatar Fields conducted a series of experiments on mice of different ages. The study included both young adult individuals (2 months) and elderly animals (18–24 months).

The results were unequivocal: old mice had significantly worse motor skills. They found it difficult to walk on a narrow beam or maintain balance on a rotating rod — a standard test for assessing coordination (Rotarod). Upon detailed analysis of brain activity, scientists found that Purkinje cells in older mice emitted electrical impulses at a much lower frequency than in young mice.

DREADD technology: controlling aging

The most important stage of the research was proving the cause-and-effect relationship. Scientists used the genetic technology DREADD, which allows for artificially increasing or decreasing the activity of specific nerve cells.

The experiment showed surprising results:

  • When the activity of Purkinje cells was artificially reduced in young mice, simulating an aged state, they instantly lost their balance and fell off the rotating rod.
  • Conversely, when the activity of these cells was stimulated in old mice, their coordination and balance improved significantly.

In another test, where mice had to pull a rope for a reward, elderly animals made many mistakes. But after stimulating the neurons, the number of errors dropped sharply. This became direct evidence that the decline in the frequency of Purkinje cell impulses is the cause of deteriorating motor skills.

Hope for new treatment methods

The discovery by Evyatar Fields and her colleagues has far-reaching implications for future medicine. As the lead author of the study noted, this offers the opportunity to develop treatments capable of preventing or slowing the aging of motor functions.

Professor Alanna Watt, a co-author of the paper, emphasizes that motor coordination is insufficiently studied in the context of aging, although its loss directly leads to the risk of falls and serious injuries in the elderly. Understanding the mechanisms of Purkinje cell function could not only help in creating programs to reduce the risk of falls but also shed light on the nature of neurodegenerative diseases such as Alzheimer's.

Today, this research opens a new chapter in gerontology, offering hope that elderly people will be able to maintain independence and a high quality of life for longer.