Paradoxical function of orexin/hypocretin circuits in a mouse model of Huntington's disease

► In HD, abnormalities in sleep-wake cycles deleteriously affect quality of life. ► Abnormalities may occur because the wake-promoting orexin system is defective. ► Surprisingly, we find that key components of the HD orexin circuitry are normal. ► Nevertheless, the day-night rhythm of orexin network activity is abnormal.