Sunday, March 26, 2017

Motor plasticity in the adult nervous system

Aguilar MJ. Recovery of motor function after unilateral infarction of the basis pontis. Report of a case. Am J Phys Med. 1969 Dec;48(6):279-88.

The purpose of this paper is to report a case of nearly complete recovery of motor function in a 72-year-old man within 4 years of a “stroke” which manifested itself clinically by a right hemiplegia. At autopsy, 6 years later, the lesion was seen to have destroyed the major portion of the left rostra1 basis pontis. The distal corticospinal tract in the left lower pons and medullary pyramid and its crossed and uncrossed continuations in the spinal cord exhibited marked atrophy, demyelination and gliosis. Examination under high magnification, however, revealed the presence of partially spared longitudinally oriented fiber bundles in both medialmost and lateralmost portions of the basis pontis and of spared, widely scattered intact myelinated axons in the pyramidal tract distal to the lesion.

After 2 years of intensive physical therapy, the patient recovered all motor function on the right except for slight clumsiness in performing skilled movements with the right hand. The disparity between the severity of the pyramidal tract lesion and the mildness of the motor disability strengthens the case for the existence of motor plasticity in the adult human nervous system.

From the article

In April 1960 the patient was hospitalized for a cerebral thrombosis with resultant right hemiplegia and difficulty with speech. Deep tendon reflexes on the right were hyperactive and there was a Babinslii sign on the right. Following discharge, physical therapy was initiated. Four months later a follow-up examination revealed marked improvement in the patient's speech and muscle power.
There remained a slight right facial weakness, slight weakness of the muscles of the right upper extremity and a more marked weakness of the right iliopsoas, hamstring and peroneal muscles. Deep reflexes in the right upper and lower extremities remained hyperactive; the plantar response on the right was equivocal.

Systematic physical therapy was continued over the following 2 years. At the end of this period the patient had recovered almost completely from the hemiplegia and speech difficulty. In May 1964 (4 years after the cerebrovascular accident) neurological examination revealed no residuals save for slight clumsiness in using the right hand for fine movements, such as when the patient buttoned his shirt or tied his shoelaces. He had no difficulty with writing, and his speech was normal. Muscle power and tone were good, and no reflex changes were present…

In reporting his progress with the development of a vision substitution system, Bach-y-Rita recounts evidence of both sensory and motor plasticity of the brain, with special reference to special retraining and rehabilitative techniques designed to enhance this innate ability of one neural system to assume the functions of another. He cites, among other work, that of Foerster, in which training led to restitution of arm and hand movements in adult humans despite anatomically verified complete pyramidal tract degeneration.


A case demonstrating recovery of motor function within 4 years after infarction of half of the basis pontis is reported, and the neuropathological findings are detailed. The patient had the benefit of prompt and extended physical therapy. Accumulating evidence from anatomical, physiological and clinical studies appears to support the concept of considerable motor plasticity in the adult brain.

Courtesy of The Brain That Changes Itself by Norman Doidge, MD.  Penguin Books, 2007.  Pp 20-23. 
Courtesy of my daughter


  1. The origin of Bach-y-Rita's understanding of brain rehabilitation lies in the dramatic recovery of his own father, the Catalan poet and scholar Pedro Bach-y-Rita, after a disabling stroke. In 1959 Pedro, then a sixty-five-year-old widower, had a stroke that paralyzed his face and half of his body and left him unable to speak.

    George, Paul's brother, now a psychiatrist in California, was told that his father had no hope of recovery and would have to go into an institution. Instead, George, then a medical student in Mexico, brought his paralyzed father from New York, where he lived, back to Mexico to live with him. At first he tried to arrange rehabilitation for his father at the American British Hospital, which offered only a typical four-week rehab, as nobody believed the brain could benefit from extended treatment. After four weeks his father was nowhere near better. He was still helpless and needed to be lifted onto and off the toilet and showered, which George did with the help of the gardener.

    "Fortunately, he was a little man, a hundred and eighteen pounds, and we could manage him," says George.

    George knew nothing about rehabilitation, and .his ignorance turned out to be a godsend, because he succeeded by breaking all its current rules, unencumbered by pessimistic theories.

    "I decided that instead of teaching my father to walk, I was going to teach him first to crawl. I said, 'You started off crawling, you are going to have to crawl again for a while.' We got kneepads for him. At first We held him on all fours, but his arms and legs didn't hold him very well, so it was a struggle." As soon as Pedro could support himself somewhat, George then got him to crawl with his weak shoulder and arm supported by a wall. "That crawling beside the wall went on for months. After that I even had him practicing in the garden, which led to problems with the neighbors, who were saying it wasn't nice, it was unseemly, to be making the professor crawl like a dog. The only model I had was how babies learn. So we played games on the floor, with me rolling marbles, and him having to catch them. Or we'd throw coins on the floor, and he'd have to try and pick them up with his weak right hand.

    Everything we tried involved turning normal life experiences into exercises. We turned washing pots into an exercise. He'd hold the pot with his good hand and make his weak hand—it had little control and made spastic jerking movements—go round and round, fifteen minutes clockwise, fifteen minutes counterclockwise. The circumference of the pot kept his hand contained. There were steps, each one overlapping with the one before, and little by little he got better. After a while he helped to design the steps. He wanted to get to the point where he could sit down and eat with me and the other medical students." The regime took many hours every day, but gradually Pedro went from crawling, to moving on his knees, to standing, to walking.(continued)

  2. (continued)Pedro struggled with his speech on his own, and after about three months there were signs it too was coming back. After a number of months he wanted to resume his writing. He would sit in front of the typewriter, his middle finger over the desired key, then drop his whole arm to strike it. When he had mastered that, he would drop just the wrist, and finally the fingers, one at a time. Eventually he learned to type normally again.

    At the end of a year his recovery was complete enough for Pedro, now sixty-eight, to start full-time teaching again at City College in New York. He loved it and worked until he retired at seventy. Then he got another teaching job at San Francisco State, remarried, and kept working, hiking, and traveling. He was active for seven more years after his stroke. On a visit to friends in Bogota, Colombia, he went climbing high in the mountains. At nine thousand feet he had a heart attack and died shortly thereafter. He was seventy-two.

    I asked George if he understood how unusual this recovery was so long after his father's stroke and whether he thought at the time that the recovery might have been the result of brain plasticity.
    "I just saw it in terms of taking care of Papa. But Paul, in subsequent years, talked about it in terms of neuroplasticity. Not right away, though. It wasn't until after our father died."

    The Brain That Changes Itself by Norman Doidge, MD. Penguin Books, 2007. Pp 20-23.