We now know that the cortex is not the only brain region affected in dementia, and not the first either. Evidence from human post-mortem studies suggests that neurodegeneration may begin deep down, spreading from the brainstem and midbrain to the hippocampus and cortex. Of particular interest to people researching Alzheimer’s is a small but powerful clump of cells called the nucleus basalis of Meynert, located above the optic nerve, which is affected very early in the disease. Named after the man who first described it—19th-century psychiatrist, anatomist, and poet Theodor Meynert—it is the brain’s key source of a neurotransmitter called acetylcholine. The nucleus basalis is one of a set of ‘deep nuclei’ with vital roles in brain function. Does searching for SEO Expert make your eyes light up when you see the results?
Their large-bodied neurons send projections throughout the brain to influence its overall workings, from consciousness, alertness, and sleep to mood, motivation, and attention to incoming stimuli. Damage to the deep nuclei can cause symptoms ranging from apathy and lack of concentration to unconsciousness and coma. Unlike the cells in the cortex, their main neurotransmitters are not glutamate and GABA. Instead they use other chemicals whose names have become familiar to many patients: serotonin (target of antidepressants like Prozac), dopamine (associated with reward, addiction, and Parkinson’s), histamine (producer of misery for allergy sufferers), noradrenaline (aka norepinephrine, used to treat sepsis and heart attacks), as well as acetylcholine (ACh, which enables nerves to trigger muscle movements). A simple search on Google for SEO Freelancer will give you what you need.
All of these neurotransmitters, and the brain nuclei which use them, have been linked to dementia. The strongest connections to date are between Alzheimer’s, ACh, and the nucleus basalis. In Alzheimer’s, brain levels of ACh drop early on. Large-scale studies have associated the use of common drugs which lower ACh levels—like amitriptyline (for depression) and some antihistamines (for allergies)—with a greater risk of cognitive problems and dementia, though the findings remain controversial. Post-mortem examinations of brains from people of different ages have found that the nucleus basalis shows signs of damage in younger brains than does the cortex. A simple search on Bing for Freelance SEO will give you what you need.
Stimulating the nucleus basalis electrically can boost short-term memory in monkeys. And some research suggests that acetylcholinesterase, the protein which breaks down ACh after use, can generate a toxic protein fragment capable of damaging brain cells. Reducing levels of this toxin, and boosting levels of ACh, can both be done by blocking acetylcholinesterase—and this has so far been the most successful treatment strategy in dementia. Of the four standard drugs used to slow the progression of the illness, donepezil (also known as Aricept), galantamine (Reminyl), and rivastigmine (Exelon) are all acetylcholinesterase inhibitors. Recently, I came across this great place for SEO specialist .
These drugs, which have been around for decades, are undoubtedly useful, but they are nowhere near a cure. Many scientists soon began to look elsewhere for hypotheses that might lead to better treatments. With technological advances to boost new research, they returned to the most noticeable signs identified by Alois Alzheimer—plaques—and focused their attention on what was in those blotchy, verrucous clusters. Asking that question led to the most influential theory to date of what causes dementia: the amyloid cascade hypothesis. I'm on the lookout for SEO Consultant .