| A major contribution regarding sensory-based | | | | These lessons were not lost on Taub, who |
| plasticity came from the work of a team of | | | | eventually survived his legal ordeals with PETA |
| neuroscientists in California. In 1996, Michael M. | | | | and the Maryland court system and ended up at |
| Merzenich, PhD, a professor emeritus | | | | the University of Alabama, Birmingham. Meanwhile, |
| neuroscientist at the University of California, San | | | | however, his interest had shifted to concerns |
| Francisco and his colleagues reported that when | | | | regarding how neuroscience discoveries can help |
| the arms and fingers of monkeys were | | | | stroke victims. Since portions of the brains of |
| exercised, the related areas of the motor cortex | | | | stroke victims die due to a failure of the vascular |
| began to expanded radically, taking over areas | | | | system to provide oxygen, Taub's concern was |
| that had previously controlled other parts of their | | | | whether the lessons from the deafferentation |
| bodies. This alone overturned the dogma that | | | | research could be used to enhance the lives of |
| stated that the adult brain cannot change. He | | | | people who survived. His subsequent research and |
| insisted that the experiences of life sculpt the | | | | clinical work sought to find out if unused (or under |
| brain and retain imprints of experiences and | | | | utilized) sectors could re-learn and take over |
| performed behaviors. He said, "These idiosyncratic | | | | servicing the functions of damaged sector(s). |
| features of cortical representation have been | | | | The conclusion from Taub's efforts became |
| largely ignored by cortical electrophysiologists." | | | | controversial since it violated conventional wisdom |
| If use stimulates the growth of neural networks, | | | | related to the treatment of stroke survivors. Up |
| would the opposite also be true? Would disuse | | | | to that point the typical treatment was to train |
| destroy networks? Certainly, this would follow the | | | | them how to compensate for the lost capabilities. |
| basic tenet of Hebbian Learning. The answer for | | | | Since many neuroscientists still believed that the |
| this came from another non-neuroscientist. In | | | | brain had no developmental potential after age 25, |
| 1981, Edward Taub, PhD, a research psychologist | | | | compensation was considered the only alternative. |
| in charge of the Institute for Behavior Research in | | | | Regardless, Taub developed a new approach that |
| Silver Spring, Maryland, was deafferenting (i.e. | | | | he called "constraint-induced movement therapy. " |
| severing the sensory nerve) on monkeys' arms. | | | | For instance, if a patient's right arm function had |
| This meant that the applicable section of the | | | | been destroyed by a stroke, his clinicians would |
| somatosensory cortex of a monkey's brain was | | | | restrain the left arm. This forced the brain to |
| not receiving input from their fingers, hands, or | | | | attempt to re-activate the abilities for the brain to |
| arms. The goal was to find out how this affected | | | | once again control and use the right arm. As the |
| the corresponding part of the brain. | | | | related somatosensory area was unavailable, the |
| Due to legal problems initiated by People for the | | | | only option was for the brain to reorganize and |
| Ethical Treatment of Animals (PETA), it took until | | | | re-install the right arm sensing and controlling |
| January 14, 1990 - when the last of first of the | | | | function to another set of neurons somewhere |
| Silver Spring monkeys was euthanized - before | | | | else in the brain. The belief here is that as a result |
| anyone obtained any appreciable results from | | | | of the pruning or differentiation - which occur |
| Taub's research. Neuroscientists led by Pons and | | | | during the first 26 months of life - and/or the |
| Mishkin sought to discover how the monkey's | | | | negative aspect of Hebbian Learning, dormant or |
| brain had reorganized after twelve years of | | | | under utilized neural networks exist and may be |
| deafferentation. What they discovered was | | | | available to take over the relocated function. This |
| astounding. When they brushed the monkey's | | | | is like saying that mentally, humans carry around |
| face, the deafferentation zone tingled with | | | | neurological "spare tires", which are available when |
| electrical activity. In fact, even a light touching of | | | | needed. Taub's further research and clinical |
| the camel hair brush produced vigorous neuronal | | | | experience showed that stroke victims can |
| responses in what was suspected to be a silent | | | | benefit from constraint therapy. This overturns |
| zone. What they discovered is that the face zone | | | | the still ascribed to belief that the brain cannot |
| of the somatosensory cortex had intruded into | | | | restructure after the 25th year of life. |
| the hand and arm zone. | | | | |