Fatal familial insomnia and agrypnia excitata.

This review summarizes the pioneering steps culminating in the identification of a novel disease, fatal familial insomnia (FFI), a hereditary prion disease. Together with Morvan's chorea and delirium tremens, FFI is characterized by an inability to sleep associated with motor and autonomic overactivation. We named this pattern agrypnia excitata, a syndrome caused by a dysfunction in thalamolimbic circuits. This review highlights the strategic role of the limbic thalamus in the central autonomic network running from the limbic cortex to the lower brainstem and regulating sleep and wakefulness.