Son YD, et al. - This study compared the functional brain activation of patients with insomnia disorder and of good sleepers without other comorbidities or structural brain abnormalities during a working memory task, using functional magnetic resonance imaging (fMRI). Findings demonstrated increased brain activation during working memory task in patients with insomnia disorder versus good sleepers, possibly suggesting compensatory brain activation to maintain cognitive performance in patients with insomnia disorder without other comorbidities.