Curcumin does cross the blood-brain barrier, but penetration is poor. There are several studies into curcumin and its anti-amyloid properties for Alzheimer's where availability in the brain is key. Researchers at UCLA (?) came up with a lipid-curcumin formulation patented as Longvida that supposedly improves blood-brain barrier penetration because of this research. It's patented by a company called Vendure Sciences, but is licensed out to several manufacturers for production. You can even buy it on Amazon. If this new tinnitus study is saying neuroinflammation in the auditory cortex is a root cause of tinnitus, then we would also want to maximize blood-brain barrier penetration. I'm taking curcumin now and slowly increasing my dose but may try this form soon.
Curcumin does inhibit secretion of TNF-alpha (what was inhibited in this study to prevent tinnitus) but it also has the same effect on several other pro-inflammatory mediators. Since the central nervous system's (CNS) immune response cells (microglia) are only located in the CNS, getting the curcumin to those cells seems like it may improve the antiflammatory effect on the auditory cortex.
Microglial cells also happen to be sensitive to potassium channels, which I believe is part of what Thanos Tzounopoulos is working on.
Vendure Sciences Longvida
Use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease
Anti-neuroinflammatory effect of curcumin on Pam3CSK4-stimulated microglial cells