it is wrong, kinda. It would be correct if brains worked like a electrical conductor, but we are more like batteries (so ions move under electrochemical potential). in short, W = V I does not apply here.

If it did, the amount of heat produced would be humongous.

here is a reddit thread I found about this - https://www.reddit.com/r/askscience/comments/5ijvvd/what_is_the_amperage_of_the_human_nervous_system/