How do I solve the mini brain game part 2?

If this is the same puzzle I think it is, once an area is white you no longer have to connect it to the network. So feel free to rotate earlier pieces to connect the rest of the pink bits to the core. Also note that grey matter does not need to be connected to however if you do and save it you can then rotate it as normal. Hope this helps.

The easiest way to beat the puzzles is to focus on making small clusters immune, then advancing to a new cluster.

Start by making all the areas surrounding the center immune - this should keep you from losing no matter how of hand the rest of the brain gets. Then focus on making as many connections as possible. Send out a pulse every time it is available to keep pink areas pink and help build immunity.

It may take a bit of time, but follow this method and you will eventually beat all the stages.