Insufficient levels of omega-3 in the long-term diets of mice affects plasticity in specific brain regions and emotional behaviour, suggests a study published online this week in Nature Neuroscience. Because previous research has suggested that some people’s diets — particularly those in western countries — lack sufficient omega-3 (n-3) polyunsaturated fatty acids, this research has the potential to inform studies of malnutrition and its comorbidity with mood disorders in humans.
Olivier Manzoni, Sophie Laye and colleagues found that mice whose mothers had eaten a diet deficient in omega-3 during their gestation and were raised on the deficient diet themselves, exhibited behaviour suggestive of increased anxiety and depression, compared to mice raised on a balanced diet. Recording from the brain tissue of these omega-3-deficient mice revealed a lack of a type of synaptic plasticity, long-term depression, specifically in two brain regions, the prelimbic prefrontal cortex and the nucleus accumbens, which have been previously implicated in emotional behavior and mood disorders. The authors also found that a specific deficit in signaling via the cannabinoid type 1 receptor was underlying the specific plasticity defect.