With BCIs and implants, you can add a near infinite number of new senses or abilities. I remember seeing something where they gave people basically an internal compass using one of those brain signal transmitter caps and tested their ability to maintain a straight line while walking blindfolded against people not using the device and everyone with the new sense was able to stay perfectly straight. The participants had a hard time describing it, but they could feel where North was and always stay aligned to whatever direction they wanted. There are now prosthetic fingers that you can control with your mind and come with a “phantom sense” similar to what amputees experience coming from the electronic limb. This shit is so cool to me.