Infections and the Brain: Spatial Memories Clouded

Fighting off a cold can be difficult, no matter the season. However, a new study shows that colds may increase inflammation levels found in the brain and hinder the organ's ability to form spatial memories.

Researchers found that increased inflammation may disrupt neural circuits commonly involved in learning and memory through a glucose metabolism decrease found in the brain's memory center.

As previous studies have linked inflammation to memory impairments and disorders, including Alzheimer's disease (AD), this and others alike show how severe infections can weaken cognitive function, particularly in older individuals.

For the study, researchers examined 20 participants who were injected with either a benign salty water injection or typhoid vaccination. This vaccination is meant to induce inflammation levels in the body.

All participants underwent positron emission tomography (PET) both before and after the injection. After each scan, participants underwent a series of virtual reality tests to study spatial memory.

Through looking at scans showing the effects of inflammation on the consumption of glucose in the brain, researchers found that those who received the vaccination also showed a reduction in glucose metabolism of their Medial Temporal Lobe (MTL), known as the brain's memory center. These same participants also scored lower in spatial memory tasks that researchers believe may have directly been affected by a change in the MTL metabolism.

"We have known for some time that severe infections can lead to long-term cognitive impairment in the elderly. Infections are also a common trigger for acute decline in function in patients with dementia and Alzheimer's disease," lead researcher Dr. Neil Harrison, a Wellcome Trust Intermediate Clinical Fellow at BSMS said, via a press release. "This study suggests that catching a cold or the flu, which leads to inflammation in the brain, could impair our memory."

Their next step is to determine how inflammation affects brain disease, including how acute infections hinder memories.

More information regarding the study can be found via journal Biological Psychiatry.