Neurodegeneration
neurophilosophy | March 10, 2010ALZHEIMER'S Disease is the most common form of dementia, affecting an estimated 30 million people worldwide. The cause of the condition is unknown, but the prime suspect is amyloid-beta (Aβ), a 42-amino acid peptide which accumulates within neurons to form insoluble structures called senile plaques that are thought to be toxic. Aβ is synthesized in all neurons; it is associated with the cell membrane, and is thought to be involved in cell-to-cell signalling, but its exact role has eluded researchers.
A new study published in the open access journal PLoS One now shows that Aβ is a potent…
neurophilosophy | March 24, 2009Optogenetics is a newly developed technique based on a group of light-sensitive proteins called channelrhodopsins, which were isolated recently from various species of micro-organism. Although relatively new, this technique has already proven to be extremely powerful, because channelrhodopsins can be targeted to specific cells, so that their activity can be controlled by light, on a millisecond-by-millisecond timescale.
A group of researchers from Stanford University now report a new addition to the optogenetic toolkit, and demonstrate that it can be used to precisely control biochemical…
neurophilosophy | February 24, 2009Alzheimer's Disease is the most common form of dementia, affecting more than 400,000 people in the U.K. and some 5.5 million in the U.S. The disease has a characteristic pathology, which often appears first in the hippocampus, and then spreads to other regions of the brain. This is accompanied by impairments in cognition, with cell death and loss of connections leading first to deficits in memory and spatial navigation, and then to global dysfunction.
The exact cause of Alzheimer's is not known, but a number genes have been implicated. One of these encodes a protein called amyloid precursor…
neurophilosophy | January 7, 2009Healthy aging is characterized by a gradual decline in cognitive function. Mental processes such as attention, memory and the ability to process information are at their peak when people are in their 30s and 40s, but as we get older, we find it increasingly difficult to focus on relevant information and to recall the names of familiar objects or people, and it takes us longer to perform mental tasks.
This age-related cognitive decline varies greatly between individuals. Some people experience little change or none at all, while others go on to develop Alzheimer's Disease or other forms of…
neurophilosophy | August 11, 2008
National Library of Medicine / Hot Medical News
This silent film clip shows several victims of a disease called kuru. They are - or rather were - members of the South Fore, a tribe of approximately 8,000 people who inhabit the Okapa subdistrict of the Eastern Highlands Province of Papua New Guinea. In the 1950s and '60s, a kuru epidemic swept through the South Fore, claiming the lives of more than 1,000 members of the tribe. Later it was established that the disease was transmitted by the tribe's practice of ritualistic mortuary cannibalism.
The word kuru means "shaking death" in the Fore…
neurophilosophy | August 2, 2008
A team of researchers from Harvard and Columbia University Medical Center have reprogrammed skin cells from an 82-year-old woman suffering from amyotrophic lateral sclerosis to generate first stem cells and then motor neurons. This is a significant advance which could aid in the development of drug treatments and cell replacement therapies for the condition and related neurodegenerative disorders.
The study, due to be published in the journal Science, demonstrates that skin cells from a chronically diseased elderly patient can be induced to de-differentiate into stem cells and then re-…
neurophilosophy | July 16, 2008
This three-dimensional reconstruction of an amyloid fibril (found at Discover) was created by Nikolaus Grigorieff and his colleagues at Brandeis University, by computer processing of a transmission electron cryomicroscopy image. It is the most detailed image yet of the abnormally folded protein which accumulates to form the senile plaques that are a pathological hallmark of Alzheimer's Disease.
The fibrils consist of a protein fragment called amyloid-beta 1-40, an insoluble forty amino acid polypeptide generated by the sequential actions of a number of enzymes on the amyloid precursor…
neurophilosophy | July 9, 2008
A new study, published today in the open access journal PLoS One, provides evidence that remaining mentally active throughout life reduces the rate of age-related neurodegeneration and may therefore stave off Alzheimer's Disease and other forms of dementia.
Valenzuela et al used the Lifetime of Experiences Questionnaire (LEQ) to estimate the extent to which 37 healthy older individuals had engaged in complex mental activity throughout their lives. They also performed functional magnetic resonance imaging (fMRI) to measure hippocampal volume in the participants, at the beginning of the study…
neurophilosophy | November 2, 2007
On November 4th, 1906, during a lecture at the 37th Conference of South-West German Psychiatrists in Tubingen, the German neuropathologist and psychiatrist Alois Alzheimer (1864-1915, right) described "eine eigenartige Erkrankung der Hirnrinde" (a peculiar disease of the cerebral cortex). In the lecture, he dicussed "the case of a patient who was kept under close observation during institutionalisation at the Frankfurt Hospital and whose central nervous system had been given to me by director Sioli for further examination". This was the first documented case of the form of dementia that…