fMRI research on brain activity validated

In a study published in Nature, a Stanford University-led team has shown that fMRI signals based on elevated levels of oxygenated blood in specific parts of the brain can be caused by activation of local excitatory neurons.

The key experiment involved turning on genetically engineered excitatory neurons in an experimental group of rats in the presence of blue light delivered via a fiber optic cable. The researchers then anesthetized the rats and looked at their brains with fMRI. They found that exciting these defined neurons with the optogenetic light produced the same kind of signals that researchers see in traditional fMRI BOLD experiments — with the same complex patterns and timing. In the control group of rats, which were not genetically altered, no such signals occurred. This showed that true neural excitation indeed produces positive fMRI BOLD signals.

The findings suggest that fMRI can now be used to study the brain-wide impact of changes in neural circuitry, such as ones that may underlie many neurological and psychiatric diseases.

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Caffeine may slow Alzheimer's

New evidence caffeine may slow Alzheimer's disease and other dementias, restore cognitive function.
Caffeine may be protective against the cognitive decline seen in aging, Parkinson's disease, dementia and Alzheimer's disease, a group of international experts has found.

Papers in the special issue of the Journal of Alzheimer's Disease, "Therapeutic Opportunities for Caffeine in Alzheimer's Disease and Other Neurodegenerative Disorders," are available free.