Apparatus is provided that includes a parenchymal electrode, configured to be implanted in brain parenchyma of a subject identified as at risk of or suffering from a synucleinopathy; and a cerebrospinal fluid (CSF) electrode, configured to be implanted in a CSF-filled space of a brain of the subject, the CSF-filled space selected from the group consisting of: a ventricular system and a subarachnoid space. Control circuitry is configured to drive the parenchymal and the CSF electrodes to clear alpha-synuclein (aSyn) from the brain parenchyma into the CSF-filled space of the brain. Other embodiments are also described.