A 74-year-old right-handed man with homonymous hemianopia from an occipital stroke presented with an abrupt behaviour change. A neuropsychological examination revealed severe cognitive impairment, apathy, amnesia and paraphasia, without sensory or motor deficit. A head computed tomography scan showed no new lesions. A diffusion-weighted magnetic resonance imaging scan of the head performed 10 days after the disease onset showed a strategic lacunar infarction in the left genu of the internal capsule (Figure, A, arrow). A computed tomography scan repeated 45 days after the disease onset showed the lacunar infarction (Figure, B, white arrow) and an old left occipital stroke (Figure, B, red arrow). The symptoms were unchanged at an 8-month follow-up visit. This condition severs the connection of the anterior and inferior thalamic peduncles with the cingulate gyrus, amygdala, and prefrontal, orbitofrontal, insular, temporal and frontal cortex, and manifests as an abrupt behaviour change.1
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