The great brain clearance and dementia debate

Wednesday, April 9, 2025

Scientists have known about a link between poor sleep and an increased risk of dementia for decades. Maiken Nedergaard, codirector of the Center for Translational Neuromedicine, says that people who report six hours or less of sleep a night are more likely to develop dementia later. “Sleep disturbances very often precede the first sign of dementia by many years.”

Brain’s Own Repair Mechanism: New Neurons May Reverse Damage in Huntington’s Disease

Monday, April 7, 2025

New research shows that the adult brain can generate new neurons that integrate into key motor circuits. The findings demonstrate that stimulating natural brain processes may help repair damaged neural networks in Huntington’s and other diseases.

“Our research shows that we can encourage the brain’s own cells to grow new neurons that join in naturally with the circuits controlling movement,” said Abdellatif Benraiss, PhD, a senior author of the study, which appears in the journal Cell Reports. “This discovery offers a potential new way to restore brain function and slow the progression of these diseases.” Benraiss is a research associate professor in the University of Rochester Medical Center (URMC) lab of Steve Goldman, MD, PhD, in the Center for Translational Neuromedicine.

It was long believed that the adult brain could not generate new neurons. However, it is now understood that niches in the brain contain reservoirs of progenitor cells capable of producing new neurons. While these cells actively produce neurons during early development, they switch to producing support cells called glia shortly after birth. One of the areas of the brain where these cells congregate is the ventricular zone, which is adjacent to the striatum, a region of the brain devastated by Huntington’s disease.

The idea that the adult brain retains the capacity to produce new neurons, called adult neurogenesis, was first described by Goldman and others in the 1980s while studying neuroplasticity in canaries. Songbirds, like canaries, are unique in the animal kingdom in their ability to lay down new neurons as they learn new songs. The research in songbirds identified proteins—one of which was brain-derived neurotrophic factor (BDNF)—that direct progenitor cells to differentiate and produce neurons.

Further research in Goldman’s lab showed that new neurons were generated when BDNF and another protein, Noggin, were delivered to progenitor cells in the brains of mice. These cells then migrated to a nearby motor control region of the brain—the striatum—where they developed into cells known as medium spiny neurons, the major cells lost in Huntington’s disease. Benraiss and Goldman also demonstrated that the same agents could induce new medium spiny neuron formation in primates.

Common Sleep Aid May Leave Behind a Dirty Brain

Wednesday, January 8, 2025

Getting a good night’s sleep is a critical part of our daily biological cycle and is associated with improved brain function, a stronger immune system, and a healthier heart. Conversely, sleep disorders like insomnia and sleep apnea can significantly impact health and quality of life. Poor sleep often precedes the onset of neurodegenerative diseases and is a predictor of early dementia.

New research appearing in the journal Cell describes for the first time the tightly synchronized oscillations in the neurotransmitter norepinephrine, cerebral blood, and cerebrospinal fluid (CSF) that combine during non-rapid eye movement (non-REM) sleep in mice. These oscillations power the glymphatic system—a brain-wide network responsible for removing protein waste, including amyloid and tau, associated with neurodegenerative diseases.

New research appearing in the journal Cell describes for the first time the tightly synchronized oscillations in the neurotransmitter norepinephrine, cerebral blood, and cerebrospinal fluid (CSF) that combine during non-rapid eye movement (non-REM) sleep in mice. These oscillations power the glymphatic system—a brain-wide network responsible for removing protein waste, including amyloid and tau, associated with neurodegenerative diseases.

“As the brain transitions from wakefulness to sleep, processing of external information diminishes while processes such as glymphatic removal of waste products are activated,” said Maiken Nedergaard, MD, DMSc, co-director of the University of Rochester Center for Translational Neuromedicine and lead author of the study. “The motivation for this research was to better understand what drives glymphatic flow during sleep, and the insights from this study have broad implications for understanding the components of restorative sleep.”

The study also holds a warning for people who use the commonly prescribed sleep aid zolpidem. The drug suppressed the glymphatic system, potentially setting the stage for neurological disorders like Alzheimer’s, which are the result of the toxic accumulation of proteins in the brain.