These images, adapted from the research paper, show that motor neurons in the spinal cord of an aged mouse (bottom) have fewer synaptic inputs than those in younger adults (top).
A new study led by researchers at Brown University’s Carney Institute for Brain Science offers a blueprint to help scientists prevent and reverse motor deficits that occur in old age.
As humans age, tasks that require coordinated motor skills, such as navigating stairs or writing a letter, become increasingly difficult to perform. Reduced mobility caused by aging is strongly associated with adverse health outcomes and a diminished quality of life.
Researchers at Brown led by Gregorio Valdez, an associate professor of molecular biology, cell biology and biochemistry, discovered that the loss of connectivity of motor neurons in the spinal cord — not the death of those neurons, as was previously thought — is what impairs voluntary movements during aging.
“This is an important fundamental discovery because it tells us that treatments are possible to prevent and reverse motor deficits that occur as we age,” said Valdez, who is affiliated with both the Center for Translational Neuroscience and the Center for Alzheimer’s Disease Research at the Carney Institute and Brown’s Center on the Biology of Aging. “The primary hardware, motor neurons, are spared by aging. If we can figure out how to keep synapses from degenerating, or mimic their actions using pharmacological interventions, we may be able to treat motor issues in the elderly that often lead to injuries due to falls.”
For the study, published on Wednesday, May 10, in the Journal of Clinical Investigation Insight, researchers examined spinal motor neurons in three species, including humans, rhesus monkeys and mice.
“These findings revealed that, as individuals age, motor neurons lose many of the connections that direct their function,” said Ryan Castro, first author of the study, who earned a Ph.D. in neuroscience from Brown in 2022.
Spinal motor neurons connect the central nervous system with skeletal muscles. The neurons receive and relay signals at synapses to activate the muscles needed to perform a specific movement. Because of their critical function, Valdez said, the loss of either motor neurons or their synapses would impair voluntary movements.
The number and size of motor neurons do not significantly change during aging, the researchers discovered. However, they undergo other processes that contribute to aging.
“Aging causes motor neurons to engage in self-destructive behavior,” Valdez said. “While motor neurons do not die in old age, they progressively increase expression of molecules that cause degeneration of their own synapses and cause glial cells to attack neurons, and that increases inflammation.”
Some of these aging-related genes and pathways are also found altered in motor neurons affected with amyotrophic lateral sclerosis (ALS).
The researchers now plan to pursue studies to target molecular mechanisms they found altered in motor neurons that could be responsible for the loss of their own synapses with advancing age.
Original Article: Old motor neurons don’t die, scientists discover — they just slow down
The Latest Updates from Bing News
Go deeper with Bing News on:
Age-related motor deficits
- Hundreds of thousands of US infants every year pay the consequences of prenatal exposure to drugs, a growing crisis particularly in rural America
Nearly 1 in 12 newborns in the United States in 2020 – or about 300,000 infants – were exposed to alcohol, opioids, marijuana or cocaine before they were born. Exposure to these substances puts these ...
- ‘Dancing with the Stars’ Icon Julianne Hough on How to Dance Your Way to Weight Loss and Better Health
“While people dance with each other and are moving together and coordinating their physical actions, we can get people in similar brain states…and in essence, that gets folks to attune to each another ...
- Neovascular Age-Related Macular Degeneration (AMD): What to Know
Neovascular age-related macular degeneration (AMD), also known as wet AMD, is a type of advanced eye disease. This version of AMD is caused by the growth of abnormal blood vessels behind your ...
- Navigating the Complexities of Cognition and Brain Aging
No, probably not, possibly not, or if it is, not in ways that are in lockstep with age-related changes in memory ... conclusion regarding dementia you must show that cognitive deficits result in ...
- Motor Outcomes in Premature Infants
Most NICU Follow-Up Clinics will continue to adjust for prematurity to 2 years of chronological age. Even compared with ... with the acquisition of early motor skills. Gross motor delays in ...
Go deeper with Bing News on:
- Neuroscientists reveal how dopamine and serotonin shape our social decisions in new breakthrough
In a pioneering study published in Nature Human Behavior, researchers from Virginia Tech and collaborators have made significant strides in understanding the neurochemical basis of social interactions ...
- The Lawnmower: First artificial motor device crafted from natural proteins
Experts craft the first synthetic protein-based molecular motor device from natural proteins called the lawnmower, tested in Switzerland.
- First synthetic protein motor creates its own fuel as it 'mows'
Protein-based molecular motors are essential for life. Now, meet 'The Lawnmower' – the first synthetic motor modeled that propels itself by harnessing the energy it creates as it cuts through fields ...
- Kenneth Mitchell Dies At 49: ‘Captain Marvel’ Actor Dies After 5-Year Battle With Motor Neurone Disease
The statement released by the family read: “With heavy hearts we announce the passing of Kenneth Alexander Mitchell, beloved father, husband, brother, uncle, son and dear friend. Ken was widely known ...
- Limerick mum of five diagnosed with Motor Neurone disease at the age of 41
Limerick mum of five diagnosed with Motor Neurone disease at the age of 41 A Limerick mother-of-five has been diagnosed with motor neurone disease when she was only 41 years old. Carol Liston O’Connor ...