In their study published in the journal Neuroimage, the researchers explained that a cognitive process responsible for alertness is particularly affected shortly after inoculation with a vaccine that causes temporary inflammation. In turn, this effect impacts the brain's readiness to reach and maintain an alert state.
"These results show quite clearly that there's a very specific part of the brain network that's affected by inflammation," said senior author Ali Mazaheri of Birmingham University's Center for Human Brain Health.
"This could explain 'brain fog,'" Mazaheri continued.
Brain fog is a common symptom of various medical conditions, such as chronic fatigue syndrome, diabetes, depression and Alzheimer's disease. It’s typically characterized by poor memory, lack of mental clarity and inability to focus.
Mazaheri said that scientists had long suspected a link between inflammation and cognition, but establishing a clear cause and effect had been difficult.
"For example, people living with a medical condition or being very overweight might complain of cognitive impairment, but it's hard to tell if that's due to the inflammation associated with these conditions or if there are other reasons," said Mazaheri.
For their study, Mazaheri and his colleagues induced temporary inflammation in 20 healthy volunteers by vaccinating them with a salmonella typhoid shot that causes few other side effects. The researchers imaged the volunteers' cognitive responses a few hours after the injection.
During imaging, the volunteers performed attention tests that engage different parts of the brain involved in "alerting," "orienting" (selection of useful sensory information) and "executive control" (used for processing conflicting information). On a different day, the volunteers received a placebo and took the same attention tests during imaging.
Results showed that inflammation affected alerting but had little effect on the two other attention processes. Mazaheri stated: "Our research has identified a specific critical process within the brain that is clearly affected when inflammation is present."
The finding can help researchers better understand the link between physical, cognitive and mental health. This, in turn, can lead to new ways of preserving cognitive function in people with obesity, kidney disease and Alzheimer's, according to psychologist and first author Leonie Balter. (Related: Chemo-induced brain fog could be linked to autism.)
"Furthermore, subtle changes in brain function may be used as an early marker [of] cognitive deterioration in patients with inflammatory diseases," added Balter. The researchers plan to further study the effects of inflammation on other areas of brain function such as memory.
Small lifestyle changes like the following can go a long toward improving your brain health: (h/t to Bustle.com)
Many of the factors causing brain fog can be prevented by making small lifestyle changes on the regular. Try these natural solutions to cure your brain fog and keep your brain healthy.
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