Violent MS attacks took away my physical functions such as vision, speech, or caused paralysis, spasticity, loss of balance, incontinence, and other frightening symptoms. It was important for me to clearly separate functions of the mind from functions of the brain and body. This was important because the human mind is intricately connected with the heart and soul. That's distinctly different from functions of the brain. (Happily, my experience with multiple sclerosis did not effect cognition so the separation was easier to make.)
I came across a website that gave an excellent distinction between the brain and the mind. I don't know where I saw it so my apologies to whoever wrote it. I can't give proper credits. The writer observed that the brain sends electrical signals to the body, the mind receives messages from the heart and soul. The brain is capable of understanding the science of art, the mind can understand the art of science. The brain learns about the universe while the mind can know the Creator of the universe. The brain calculates and understands, the mind perceives and can 'know.' It is the mind that conceives darkness and desires evil, the brain invents weapons. The brain learns from the physical senses while the mind learns the emotional and spiritual senses. The brain understands what makes a human being live but it is the mind that is able to understand what gives life purpose, and meaning of being.
During my darkest times of neurological terror that could not be stopped, it was very important that I valued my mind over my body. My mind was all I could rely upon: It could reason and discern. But there came a time in the midst of catastrophic circumstances when I faced the possibility of quadriplegia and a desperate and risky medical therapy was taken to try and prevent it. I could not reason about what was unreasonable. Defeat and a sense of hopelessness threatened to overtake me.
I was my mind—with its connection to my heart and soul—to
which God appealed. Intellect alone would have given up: Suicide. I spent hours, days and months on my sick-bed: praying, seeking, listening with my heart not my ears for that still small voice of God.
"For I know the thoughts that I think toward you, says the Lord, the thoughts of peace and not of evil, to give you a future and a hope. Then you will call upon me and go and pray to Me, and I will listen you. And you will seek Me and find Me, when you search for Me with all your heart." — Jeremiah 29.11-13.
I had to surrender to my spiritual being, still underdeveloped, and wait upon God to bring me into clearer focus with my human being. That interior being is rooted inextricably with the Image of God that was endowed upon me from my beginning when I was conceived within my mother. I had to look beyond my electric wheelchair, my creeping paralysis, and calm my sense of panic and terror to listen for that still small voice whispering to my soul, like a gentle breeze: "Be not afraid, I AM with you."
"Come to Me, all you who labor and are heavy laden, and I will give you rest. Take My yoke upon you and learn from me, for I am gentle and lowly of heart, and you will find rest for your souls. For My yoke is easy and my burden is light." -- Jesus (Matthew 11.28-29.)
It is at such moments when an individual lives centuries and descends into the sweet spiritual abyss of the soul to see with our hearts rather than through the blur of tear-filled eyes. It is then that a human being can truly begin to comprehend and understand the meaning of being human.
"Therefore, I urge you, brothers and sisters, in view of God's mercy, to offer your bodies as a living sacrifice, holy and pleasing to God—this is your true and proper worship. Do not conform to the pattern of this world, but be transformed by renewing your mind. Then you will be able to test and approve what God's will is —his good, pleasing and perfect will. For by grace given me I say to every one of you: Do not think of yourself more highly than you ought, but rather think of yourself with sober judgment, in accordance with the faith God has distributed to each of you." Saint Paul, (Romans 12.1-3.)
While Christians are to offer their bodies as a living sacrifice to God, some of us have little more to offer than a living carcass. The body degenerates with time (some faster than others). The mind continues to grow with time. It has been my mind that renews according to God's will, gradually revealing inklings of liberty that awaits me (and you). For those Christians afflicted with dementia or Alzheimers, they and their loved-ones can rest assured their memories and faith are safe in Christ's keeping. Nothing is lost.
 Psalm 4.4.
 Cf. 1Kings 19.12-13.
 See Matthew 14.27,