Brain inflammation disrupts memory networks

September, 2014

A rat study has demonstrated that cytokines (immune system signaling molecules) impair communication among neurons in the hippocampus. The increased cytokine levels affected complex discrimination memory, that is, the ability to differentiate among generally similar experiences.

In the study, the rats were exposed to two similar environments, one of which was associated with a mild foot shock, making them reluctant to enter that environment. When some rats were then given a low dose of a bacterial agent to induce a neuroinflammatory response, leading to cytokine release in the brain, they became no longer able to distinguish between the two environments.

Analysis of changes in the activity patterns of hippocampal neurons suggested that cytokines impaired recall by disrupting the function of specific neuron circuits, taking the neural network that had learned the discrimination back to the state it had been before learning took place.

The finding may help explain "chemobrain", and suggests that an intervention aimed at reducing inflammation might be effective approach.

Czerniawski, J., & Guzowski, J. F. (2014). Acute Neuroinflammation Impairs Context Discrimination Memory and Disrupts Pattern Separation Processes in Hippocampus. The Journal of Neuroscience, 34(37), 12470–12480.

Related News

A pilot study involving 22 breast cancer patients currently receiving chemotherapy (mean age 54), has found that those with higher levels of inflammatory biomarkers did significantly worse on tests for short-term visual memory.

Chemo-brain common among women with breast cancer

A six-week study involving 619 cancer patients has found that those who took part in a simple home-based exercise program significantly reduced their cognitive impairment ('chemo-brain').

The issue of ‘chemo-brain’ — cognitive impairment following chemotherapy — has been a controversial one.

Cancer survivors who underwent chemotherapy often suffer long-term cognitive problems. Until now, most research has been occupied with establishing that this is in fact the case, and studies investigating how to help have been rare.

Women who received a once-standard type of chemotherapy regimen for breast cancer between 1976 and 1995 have been found to score worse on cognitive tests than women who never had cancer.

A recent study of cancer survivors has found that many survivors still suffer moderate to severe problems with pain, fatigue, sleep, memory and concentration three to five years after treatment has ended.

A study involving 1426 long-term survivors of childhood cancer (survivors of eight different childhood cancers who were treated between 1970 and 1986) has revealed cognitive impairment in over a fifth.

Confirming earlier indications from small studies, a very large nationwide survey has found that people who have had cancer are 40% more likely to experience memory problems that interfere with daily functioning.

Over the years I’ve reported on a number of studies investigating the effect of chemotherapy on the brain. A new study uses brain imaging, before and after treatment for breast cancer, to show that there is an anatomic basis for “chemobrain” complaints.


Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news