Neurological Terms beginning with A

Glossary of neurological terms
Click one of the letters above to go to the page of all terms beginning with that letter.
acetylcholine search for term

is what is known as a neurotransmitter — a chemical produced by brain cells which transmits information within the brain. Acetylcholine is vital for memory, attention and thought. Acetylcholine-producing cells are among the first to die in Alzheimer's disease. Parkinson's disease, dementia due to multiple strokes, multiple sclerosis and schizophrenia, are all, like Alzheimer’s, associated with lower levels of acetylcholine in the brain.

acetylcholinesterase search for term

an enzyme which breaks down acetylcholine

actin search for term

a cytoskeletal protein present in all cells

adenosine triphosphate search for term

the chemical produced by the mitochondria that supplies the energy for cells to function; it also bonds at nerve terminals for normal neural communication.

advanced glycation endproducts search for term

through some chemical process not yet well understood, proteins can be permanently and irreversibly modified; these modified proteins then interact with other chemicals to form a variety of compounds known as advanced glycation endproducts. Advanced glycation endproducts have been implicated in numerous diseases including diabetes, cancer, atherosclerosis, and Alzheimer’s disease.

AF267B search for term

new drug compound that successfully reduced plaques and tangles in the hippocampus in mice.

alpha1-antichymotrypsin (ACT) search for term

is a serin protease inhibitor. Production of ACT increases in brains with Alzheimer's disease, and this strongly increases the build-up of amyloid proteins. How it does this is not yet known.

Alzhemed search for term

an experimental drug now in human clinical trials for treatment of mild-to-moderate Alzheimer's, Alzhemed works by binding with amyloid beta to prevent plaque formation.

amino acids search for term

the building blocks of life. These are the 20 different kinds of molecule that chain together to form proteins.

amyloid beta peptides search for term

peptides derived from amyloid precursor protein, these fragments of amyloid beta are the main protein component of plaques, and probably a major cause for the their toxicity. They are thought to bind to a receptor in the brain, blocking the signals needed for learning and memory. The peptides come in two forms: A-beta 42 and A-beta 40. A subunit of gamma-secretase, the protein CD147, is now thought to regulate the production of A-beta 42. Amyloid beta peptides routinely circulate in the human bloodstream, where they are harmless. Early beta amyloid accumulation within neurons is the trigger for the onset of memory decline in Alzheimer's.

amyloid beta protein cascade search for term

the process by which APP is clipped by the beta form of secretase, then further clipped by gamma secretase, resulting in amyloid beta peptides.

amyloid precursor protein search for term

is found in many tissues besides brain, but its functions are largely unknown. It is anchored across the cell membrane, so part of it is inside and part of it is outside the cell. Enzymes called secretases snip it apart into three protein fragments, two of which are released outside the cell and one inside. One of those which is found outside the cell is made of amyloid beta peptides. It's speculated that the creation of amyloid plaque is a byproduct of a misregulation in normal APP processing. Mutation in the APP is thought to be involved in early-onset Alzheimer's; the APP gene is located on chromosome 21, at 21q21.

amyloid ß-derived diffusible ligands search for term

or oligomers. Tiny toxic proteins only discovered a few years ago, they attack specific synapses rather than the neurons themselves. The synapses attacked are those where there is a gene linked to memory that is normally expressed, thus disrupting the normal expression of the gene. ADDLs are a form of amyloid beta, but differ from plaques in that they are very much smaller, are soluble and diffuse between brain cells until they find vulnerable synapses. They are found in much higher quantities in the brains of those with Alzheimer's, and it is theorized that they accumulate at the beginning of Alzheimer's disease and block memory function. The process is predicted to be reversible, because the ADDLs disrupt communication between cells rather than destroying the cells. There is accumulating evidence that it is these, rather than amyloid fibrils, that are the principal pathogenic species in Alzheimer's disease.

anthocyanins search for term

perhaps the most important of the visible plant pigments, responsible for the reds, purples, and blues you see in plants, they have strong antioxidant properties; found in fruit such as blackberries, raspberries, blueberries, etc, and vegetables such as red cabbage.

apolipoprotein E search for term

is a protein whose main responsibility is transporting cholesterol out of the cell. Too much of this protein results in an increase in the level of free cholesterol in the cells. An allele of the gene responsible for this protein has been identified as a major genetic risk factor for Alzheimer's

apolipoprotein-E gene search for term

the e4 allele of the apolipoprotein E gene has been identified as a major genetic risk factor for Alzheimer's. There are three versions (alleles) of the APOE gene; the most common is e3, present in over half the population. Those who inherit one copy of the e4 allele are at higher risk of developing type 2 Alzheimer's, a late-onset form; those who inherit two copies are at greater risk. Most people with familial hypercholesterolemia have 2 copies of the e4 allele. One study suggests having the e4 allele is particularly risky in combination with a small head size. Similarly, calorie and fat intake appear to increase the risk of developing Alzheimer's in those with the allele. An Australian study has more recently identified the -491A allele as another risk factor. The same study found that people with these alleles were more likely to complain of memory difficulties. APOE is located on chromosome 19. A gene on chromosome 10 has also recently been identified as significantly increasing the risk of Alzheimer's when found in combination with APOE e4.

Arc search for term

a protein involved in memory

Aricept search for term

the brand name for the generic drug donepezil

astrocytes search for term

star-shaped glial cells that fill in the space between neurons and maintain the extracellular environment with the right concentrations of chemicals to support neurons, such as taking up neurotransmitters released by neurons. Astrocytes are the most numerous glia, and the most mysterious. They now appear to be critically involved in neurogenesis.

axon search for term

a long projection extending from the cell body, that carries the output of the neuron away from it.

Aß*56 search for term

an amyloid-beta protein different from that involved in plaques; shown to be directly involved in memory loss.