As we see today the interconnection between the brain and computing is becoming thinner day by day, we could imagine a future that where we could install additional artificial neurons.
In a world where you could routinely buy these type of extensions, you would be accustomed to connect/disconnect a part of the brain.
The world building question is: How would it be like removing or adding such a neuronal mass? Would you loose some memory/ability, would it be more like an effort scale? Would you easily pinpoint core abilities that could be just switched on/off? would it be difficult to harness this additional neural network, and when you disconnect from it, what changes could you notice? Could you pinpoint an aspect of the memory of a fact/event that would be stored only in the extension? Would it be valuable to have different extensions? I guess you could not exchange them, and they would not be exchangeable because they would have been trained with your brain configuration, but what would you feel if you just tried once, or a little longer?
To restrain the complexity of the question, I'm considering these extensions as:
- giving only more neuronal networks matter (no complex emotional or new organs connected with hormones release or any important chemicals needed by the body).
- being lumps of artificial matter that you would wear (and by this mean connect) with various interfaces directly to your neurons.
- The max section of communication could be considered up to the full 2d surface of coverage of your head the extension would provide (each organic neurons of this surface could have its state mirrored technologically with an artificial version on this surface in a 2-way sync)
- The technology behind the artificial neuronal network wouldn't be conceptually far from the virtual ones we use today, except these would be physical and would be comparable in density and mass to brain's grey matter.
- These would be bought blank, but wouldn't wear off or need replacement even on a life-time period. They would take probably weeks, month, years to harness and produce a noticeable effect.
- They would be an everyday life object that we would have a lifetime to be accustomed to, especially since early childhood.
- There are no technology allowing to control what happens with the neurons more than just interacting with the interface they give through our natural brain's neurons connected to artificial neurons on the surface of connection.
- You won't have any technological means to help you storing a specific memory or ability inside an extension.
- An individual would have access to different extensions (bought by the individual or provided by its job or by a state) for different occasions with bigger/smaller mass
- there are no limit to the actual time individuals can wear such a peripheral and this would vary depending on the individual's habit.
- You can consider the whole surface of the brain accessible to these extension (either because the whole brain is accessible directly after surgery considered as very common, systematic and accessible, or because of a technology allowing to 2 way connections with individual neurons through the bone.)
- A typical extension would be the size of 200gr meat steak shaped lump that you would wear on the back of your head that you could wear on any occasions. But you could think of whole helmet going up to 5 kilograms of artificial neuronal matter (that you wouldn't wear in casual occasions, but typically for work).
- A typical individual would easily possess between 1 to 5 of these 200gr meat steak shaped extensions and would wear one or two, 90% of the time.
- For some cultural reasons (like natural life style or religious beliefs or obscure medical reasons), it wouldn't never be integrated as a non-removable part, and humans would value the fact to be able to remove these peripherals from time to time to enjoy life extension-less.
- The location of extensions on your head could be of importance (visual processing is on the back of the brain, language in Broca's area).