Current brain-computer interfaces have 96 needle-like electrodes, so can interface with 96 neurons. That produces an enormous amount of data at the sampling rates used, but is already being used for things like controlling robot arms.

In 7.5 years, perhaps it'll be up to 192 neurons, if the connected computers and processors can keep up with the data flow.

7.5 years after that, maybe it'll be up to 384. Etc.