Researchers from the University of Birmingham (in the U.K.) have discovered a pattern between levels of mental sluggishness with certain types of illnesses. This is an important area of inquiry since millions of people who suffer with a chronic medical condition often report that they experience mental fatigue. This mental weariness is often described as ‘sluggishness’. In severe cases the condition can be as debilitating as the disease itself.
Link between this mental fog and inflammation
The new study clearly demonstrates how inflammation leads to a negative impact on the brain’s readiness to reach and maintain an alert state.
According to lead researcher Dr Ali Mazaheri: “Scientists have long suspected a link between inflammation and cognition, but it is very difficult to be clear about the cause and effect. 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.”
For the supporting experiments, these looked at the area of the brain linked to visual attention.
The study involved taking a set of 20 young male subjects. The volunteers were administered a salmonella typhoid vaccine. One effect of the vaccine is to trigger temporary inflammation. With some additional studies, water was administered as a placebo (with each subject being unaware as to what the test vaccine contained).
After this, each subject was tested for cognitive responses. The test involved the subjects viewing simple images on a computer screen a few hours following the injection. During this time, their brain activity was measured to assess the level of attention tests by using electroencephalography (EEG). The level of inflammation was assessed via a blood test.
Attentiveness was assessed by considering:
“Alerting” which involves reaching and maintaining an alert state.
“Orienting” which involves selecting and prioritising useful sensory information.
“Executive control”, which is used to resolving what to pay attention to when available information is conflicting.
The brain was shown to have neurophysiological sensitivity to acute mild inflammation in relation to its neural network. The experimental data demonstrates that inflammation specifically affected brain activity related to staying alert. However, other attention processes were not affected by inflammation.
Research implications
Dr Ali Mazaheri points out that the research, by identifying a specific critical process within the brain that is clearly affected when inflammation is present, new detection regimes can be established and potential new treatment options developed for those with mental health issues. This will require further testing and assessment.
Research paper
The research findings have been published in the journal NeuroImage. the accompanying research paper is titled “Selective effects of acute low-grade inflammation on human visual attention.”
Related news
In other research of interest, a new study from Duke University finds an abnormality in visual regions of the brain which is connected with a person’s general risk for mental illness. The research findings suggest a signature abnormality is shared between common forms of mental illness. The data may help clinicians to assess a patient’s general risk for developing a mental illness.
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue.
Last week we examined a new study that shows how white noise can assist with certain types of hearing loss. This is evidenced by a continuous white noise background helping pure sounds to be perceived more precisely.
The week before we looked at new evidence which demonstrates that the key to living longer is to get a good amount of sleep. This research focus is with epigenetics. Here scientists have mapped changes in gene expression in people who died between 60 and 100 years old. The purpose was to understand how changes in gene expression correlated to longevity, with the conclusion that a good sleep boosts life-expectancy.
