Researchers in the department of psychiatry at the University of California, San Diego believe they’ve found a distinct link between memory deficits and insomnia.
For the study, 25 patients with primary insomnia and 25 healthy sleepers underwent functional MRI while performing the N-back working memory task. Sleep was measured using self-reports and actigraphy, and patients underwent polysomnography for two consecutive nights.
“We found that after undergoing MRI, insomnia subjects did not properly turn on brain regions critical to a working memory task and did not turn off ‘mind-wandering’ brain regions irrelevant to the task,” said Sean P.A. Drummond, PhD, associate professor in the department of psychiatry at the University of California, San Diego, in a press release. “Based on these results, it is not surprising that someone with insomnia would feel like they are working harder to do the same job as a healthy sleeper.”
The results, which were published in the journal Sleep, reveal that patients with insomnia did not differ significantly from healthy sleepers in objective cognitive performance. However, as the working memory task increased in difficulty, patients with insomnia showed reduced activation of task-related working memory regions, particularly in the right dorsolateral prefrontal cortex. What’s more, patients with insomnia exhibited increased activation of default mode regions, which are typically active when the mind is “wandering.”