Alzheimer’s disease appears to damage the brain in two phases, and treatment before the latter stage, when “suddenly things get really bad,” is key.
They also suggest protecting vulnerable inhibitory neurons might make a difference, according to the study published last month in Nature Neuroscience.
While excitatory neurons activate other neurons when sending electrical signals through the brain, inhibitory neurons restrain other neurons, making them less likely to fire.
These particular inhibitory neurons release a chemical called somatostatin, “which is known to decline in Alzheimer’s patients,” per the outlet.
(More Alzheimer’s disease stories.)
Treatment is crucial before the later stage, when “suddenly things get really bad,” as Alzheimer’s disease seems to harm the brain in two stages. Ed Lein, a senior investigator at the Allen Institute for Brain Science, said as much in a Medical News Today article. He and almost 100 other researchers examined over 3-4 million cells from the brains of 84 individuals who passed away at the age of 65 or older, all but nine of whom had Alzheimer’s disease. Lein tells National Public Radio that they discovered an early stage of the disease “where there’s a very slow increase in the amount of pathology.” He also says he was shocked to learn that a tiny subset of neurons called somatostatin inhibitory neurons, which have received little attention, are the first cells to die off.
According to a press release from the National Institute on Aging, which provided funding for the study, “many of the traditionally studied changes [related to Alzheimer’s] happening rapidly” in the second stage of the disease, which follows the first stage, which is also characterized by the slow accumulation of plaques and activation of cells related to immune function but no cognitive effects. This second stage occurs “with the appearance of memory problems and other symptoms.”. Thus, according to Lein and colleagues, therapies are most likely to be effective if initiated prior to the second stage. According to the study that was published in Nature Neuroscience last month, they also imply that safeguarding susceptible inhibitory neurons may have an impact.
Inhibitory neurons inhibit other neurons, reducing their likelihood of firing, whereas excitatory neurons send electrical signals through the brain that activate other neurons. It is believed that brain disorders are caused by disturbances in the so-called global excitatory/inhibitory balance, which is essentially maintained by the two. NIA Director Dr. Richard Hodes tells NPR, “It may be that the loss of these [somatostatin] inhibitory neurons is causing a hyper-excitatory state which may be contributing to disease.”. A substance known as somatostatin, “which is known to decline in Alzheimer’s patients,” is released by these specific inhibitory neurons, according to the outlet. According to MNT, they are also mostly limited to the area of the brain linked to language, memory, and vision. More stories about Alzheimer’s disease. ).
