While I totally agree with you that chips in your brain are nothing to be afraid of themselves and can be a great help (especially as you mnetioned the brain pacemakers for parkinson's disease) you have to make sure to create an inert system.
You have to make sure no one can access it from a distance so don't even think about implanting a chip with something like WiFi or Bluetooth and as it is with pacemakers for the heart you probably also don't want to get into an MRI if the device creator did not specifically design it to be resistant to an electromagnetic impulse like that.