I believe in the concept of the haptic nervous system, where the brain and neuronal cells are distributed along the nerve fibres of the whole body, not just resident in the skull. I therefore believe that body and brain are connected and that learning is also a physical phenomena.
I know how Internet has changed my body, not really how it changed my way of thinking.
My short sight has remained fairly stable: actually reading from a screen is forcing neither the retina nor the muscles of my eyes. Therefore I could avoid recurring to laser therapy so as to correct retinal tension, as it happened to me in the early nineties. In that period I used to study architecture and drawing by hand meant a great stress to my eyes, almost causing holes and retinal detachment.
Due to the position in front of the screen of the computer and to the lack of physical exercise deriving by a too intense use of the Internet (to every advance in connection speed more hours of it) I developed two herniated discs in the cervical region (detected in 2005) and two herniated discs in the lumbar region (detected in 2008). The first two provoke numbness and a certain diminution of strength in my thumbs, while the two last ones determine sciatica pains in my right leg, which is variable but aggravated by the position used to navigate the Internet for long hours. So it hurts more in the weekdays. There was anyway a family history of hernias.
The numbness of the thumbs, a disorder deriving from the compression of the spinal nerves in my neck, is aggravated by the use of portable devices from which to access the web, where the thumbs are the main fingers to be used, so that muscular fatigue is a secondary factor of stress. iPhones should carry some disclaimers about that.
On the other hand the information provided by the Internet and then stored in lightweight portable devices such as pen drives of external hard-disks save me from carrying heavy books around, therefore protecting my back. I can also shop online waiting for the goods to be delivered at my door. These were the main changes, registered so far.
The Internet also offers me with an instant and fast set of information about the pathologies that I know I suffer from and the new symptoms that arise suddenly, thus sustaining a mild form of hypochondria. It seems ironical that due to the easiness of this information, rather than thinking more of the world outside me, I tend to think more about myself and how I feel and what this could mean (not always, but quite frequently): I surf the website of some obscure osteopath in Nebraska to then come back at my petty little problems.
So I would say that at least Internet made me a more informed patient. But I am not sure if that knowledge is really valuable: the paediatrician of my daughters forbid me to check online about the illnesses they might be suffering, as my inclination to self-learning tends not to regard only myself but all my family and as the grim perspective that I tend to imagine can be very wrong. I wonder if the difficulty of getting information before the Internet was not somehow protecting us from a new diffused expertise as the one of Bouvard and Pecuchet.