GO:0033326

The regulated release of cerebrospinal fluid (CSF) from the choroid plexus of the lateral, third and fourth ventricles. The cerebrospinal fluid is a clear liquid that located within the ventricles, spinal canal, and subarachnoid spaces. [GOC:ln, http://users.ahsc.arizona.edu/davis/csf.htm, PMID:10716451]