Older news items (pre-2010) brought over from the old website
Repeated common infections may lead to memory deficits over a lifetime
A mouse study suggests that over the lifetime of an individual, a picornavirus-related infection could have a permanent effect on memory late in life. Picornaviruses are the most common infectious viral agents in humans. They include rhinoviruses, enteroviruses, encephalitis, myocarditis, meningitis, and those that cause foot-and-mouth disease, polio and hepatitis A. Generally individuals contract two or three enterovirus and/or rhinovirus infections each year. In the study, mice infected with an encephalomyelitis virus (comparable to the human poliovirus) had difficulty learning to navigate a maze designed to test various components of spatial memory. The degree of memory impairment was directly correlated to the number of dead brain cells in the hippocampus. "Our findings suggest that picornavirus infections throughout the lifetime of an individual may chip away at the cognitive reserve, increasing the likelihood of detectable cognitive impairment as the individual ages. We hypothesize that mild memory and cognitive impairments of unknown etiology may, in fact, be due to accumulative loss of hippocampus function caused by repeated infection with common and widespread neurovirulent picornaviruses."
Buenz, E.J., Rodriguez, M. & Howe, C.L. 2006. Disrupted spatial memory is a consequence of picornavirus infection. Neurobiology of Disease, 24 (2), 266-273.
http://www.eurekalert.org/pub_releases/2006-10/mc-mcs101706.php
Immune function important for cognition
New research overturns previous beliefs that immune cells play no part in — and may indeed constitute a danger to — the brain. Following on from an earlier study that suggested that T cells — immune cells that recognize brain proteins — have the potential to fight off neurodegenerative conditions such as Alzheimer’s, researchers have found that neurogenesis in adult rats kept in stimulating environments requires these immune cells. A further study found that mice with these T cells performed better at some tasks than mice lacking the cells. The researchers suggest that age-related cognitive decline may be related to this, as aging is associated with a decrease in immune system function, suggesting that boosting the immune system may also benefit cognitive function in older adults.
Ziv, Y., Ron, N., Butovsky, O., Landa, G., Sudai, E., Greenberg, N., Cohen, H., Kipnis, J. & Schwartz, M. 2006. Immune cells contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood. Nature Neuroscience, 9, 268 - 275.
http://www.eurekalert.org/pub_releases/2006-01/acft-wis011106.php