Non-rapid eye movement (NREM) sleep is associated with increased cerebrospinal fluid (CSF) flow in mammals, but this link has not been studied in birds. Here, the authors show that in pigeons, REM sleep is associated with activation of visual brain regions and a drop in CSF flow, suggesting that REM sleep functions occur at the expense of waste clearance during NREM sleep.
- Gianina Ungurean
- Mehdi Behroozi
- Niels C. Rattenborg