Definitely not IN the brain, electronics and digital technology advancement would require an operation every five years or so.
But on the skull? Think 'Frankenstein'. Replaceable horns, or to be fashionable, disguise then as 'hair buns' or 'pony tails' or such. Even skull caps and 'baseball caps'.
So how do we interface them? Already solved. China is leading in the technology.
Abstract Hydrogel bioelectronics that can interface biological tissues
and flexible electronics is at the core of the growing field of
healthcare monitoring, smart drug systems, and wearable and
implantable devices. Here, a simple strategy is demonstrated to
prototype all-hydrogel bioelectronics with embedded arbitrary
conductive networks using tough hydrogels and liquid metal. Due to
their excellent stretchability, the resultant all-hydrogel
bioelectronics exhibits stable electrochemical properties at large
tensile stretch and various modes of deformation. The potential of
fabricated all-hydrogel bioelectronics is demonstrated as wearable
strain sensors, cardiac patches, and near-field communication (NFC)
devices for monitoring various physiological conditions wirelessly.
The presented simple platform paves the way of implantable hydrogel
electronics for Internet-of-Things and tissue-machine interfacing
They would be easily removeable, and swappable. Snap on snap off. "Switching your mind to focus on another task' would be literal - if one switched from, say, building a boat to reading philosophy, one need only switch the data pack from 'maker/builder' to 'thinker/philosopher' 'Changing one's mind' would take on a whole new meaning. If one is interrupted during a meeting, one might say 'just a sec, I need to switch my pony tail'.
'Learning' could be done during sleep - remove the data pack, plug it into an upgrade interface, and sleep away while the latest advancements in quantum mechanics are downloaded.
Or how about swapping out your 'mind' with your nerdy kid sister, when going on that 'special date' with that 'hunk' you really want to impress? You know, the way one sister 'borrows' that special dress from their sibling? 'Shrinking it in the wash' would become 'corrupting the data' by an incorrect download. "You wiped out Calculus and replaced it with Zingmoda Vids? I have an EXAM tomorrow!!!!!!!"
The problem, however, will not be addressed by technology, but by algorithms - data search and retrieval. For a lot of us, the issue is not that we cannot remember, but that we can not recall the memory. When we refresh our 'minds' on the topic, how often do we retort "I knew that!!!!!'