A study from McGill University has found a direct link between age-related declines in neuronal activity in the cerebellum, worsening motor skills, gait, balance and agility. These functions are known to decline with age. This study points out how changes in Purkinje cells drives this decline and translates into measurable changes in behaviour and physical function.
Purkinje cells are specialised neurons in the cerebellar cortex. They are large, inhibitory neurons that act as primary output channel for motor coordination, balance, and fine motor learning. They spontaneously fire electrical signals.
Thestudyprovides new hope for extending health span, improving quality of life and independence in elderly people.
Two separate tests were conducted on groups of mice to study the impact of ageing. Each test included two groups of mice: young adults (two months old) and elderly mice (18 to 24 months old). One experiment involved crossing an elevated beam and staying on a rotating rod (Rotarod). The other one was to pull a one-meter string for a cereal reward( both groups were trained to pull the string). Older mice performed poorly on both the coordination tasks.The behaviour mirrors motor decline in human beings.
The team then recorded electrical activity from Purkinje cells and found significantly lower firing frequencies in older mice. To determine whether the the low firing frequency was the cause behind the decline, a genetically targeted tool called DREADD (Designer Receptors Exclusively Activated by Designer Drugs) was used. It is a widely used chemogenetic technology in neuroscience and biomedical research that allows for precise, non-invasive control of cellular activity, such as neuronal silencing or activation, using engineered receptors.
When the DREADD was turned on for young mice and Purkinje cells were made to fire at Lowe rate, they jumped sooner from the Rotarod, behaving like older mice. The reverse was also true, upon boosting the neuron firing, the older mice performed better. The other test also showed similar results, the performance of older mice improved upon increasing the firing of Purkinjie cells.
This study could lead to an approach to improve the function of an ageing brain, promising an improvement in motor coordination, a reduction in falls, and an extension of human health span. By restoring neuronal activity, it may be possible to reverse aspects of functional deterioration in ageing brains.
Can boosting cerebellar activity help prevent the falls that often threaten independence in old age?