Video: New Research Discovers Independent Brain Networks Control Human Walking

Kennedy Krieger Institute Study Enhances Understanding of Brain Plasticity

and Motor Skills, Signaling Advancements for Future Rehab Practices

Aug 07, 2007, 01:00 ET from Kennedy Krieger Institute

    BALTIMORE, Aug. 7 /PRNewswire-USNewswire/ -- In a study published in
 the August issue of Nature Neuroscience, researchers at the Kennedy Krieger
 Institute in Baltimore, Maryland found that there are separate adaptable
 networks controlling each leg and there are also separate networks
 controlling leg movements, e.g., forward or backward walking. These
 findings are contrary to the currently accepted theory that leg movements
 and adaptations are directed by a single control circuit in the brain. The
 ability to train the right and left legs independently opens the door to
 new therapeutic approaches for correcting walking abilities in patients
 with brain injury (e.g., stroke) and neurological disorders (e.g., cerebral
 palsy and multiple sclerosis).
     To view the Multimedia News Release, go to:
     Using a split-belt treadmill to separately control the legs, Kennedy
 Krieger researchers Dr. Amy Bastian and Julia Choi studied forty healthy
 adults and tracked each person's ability to learn various walking
 exercises. Utilizing specialized computer software and infrared tracking
 devices placed on key joints, researchers found subjects could store
 different walking patterns for forward versus backward walking
 simultaneously, with no interference between the two, revealing that
 separate brain systems control the two directions of walking. Surprisingly,
 people could also walk easily with one leg moving forward and the other
 backward, a pattern referred to as "hybrid walking." Adaptation of hybrid
 walking, in which varying speeds were applied to legs walking in opposite
 directions, was found to interfere with subsequent "normal" forward and
 backward walking. The combined results demonstrate there are distinct brain
 modules responsible for right/forward, right/backward, left/forward and
 left/backward walking. Most significantly, these modules can be
 individually trained, which would be critical for rehabilitation focused on
 correcting walking asymmetries produced by brain damage.
     "The notion that we can leverage the brain's adaptive capacity and
 effectively 'dial in' the patterns of movement that we want patients to
 learn is incredibly exciting," said Dr. Amy Bastian, senior study author
 and Director of the Motion Analysis Laboratory at the Kennedy Krieger
 Institute. "These findings significantly enhance our understanding of motor
 skills, effective therapeutic approaches and the true adaptive nature of
 the brain."
     The walking adaptations studied here represent a form of short term
 learning from practicing on this unusual treadmill. Investigators set
 different speeds for each belt of the treadmill causing subjects to walk in
 an abnormal limping pattern. However, within 15 minutes subjects adapted
 and learned to walk smoothly with a normal pattern and rhythm, as verified
 by computer models. This indicates that the phenomenon of brain plasticity
 can occur in short intervals. When subjects returned to normal conditions
 (same speed for the two legs), this adaptation caused an after-effect that
 resulted in a limp that lasted for five-to-ten minutes as they "unlearned"
 the correction. Regardless of how hard subjects tried, they were unable to
 stop this after-effect, because walking patterns are controlled by
 automatic brain systems that recalibrate themselves according to current
     "As we understand more about the way the brain learns, relearns and
 adapts in relation to motor skills, physical therapy professionals have a
 vastly expanding toolbox from which to tailor therapeutic interventions,"
 explains Gary Goldstein, MD, President and CEO of the Kennedy Krieger
 Institute. "This study and other research from Kennedy Krieger's Motion
 Analysis Laboratory provide a glimpse into the rehabilitative potential
 made possible through the pairing of our talented researchers and
 cutting-edge technologies."
     Past studies by Bastian and her colleagues have found that certain
 types of brain damage interfere with walking ability, while others do not.
 For example, individuals with damage to the cerebral hemispheres can adapt
 while those with damage to the cerebellum are rarely able to.
     This body of work sheds light on the specificity of walking adaptations
 and demonstrates that patients with certain types of brain damage can store
 a new walking pattern in the short term. Based on these findings, Bastian's
 goal is to learn how to make that pattern last for an extended period.
 Currently, Bastian is planning a study of stroke victims in order to test
 the long-term benefits of split-belt treadmill therapy. She is also
 studying children with more extreme forms of brain damage, including those
 that undergo a hemispherectomy, a neurosurgical procedure to treat seizures
 in which an entire half of the brain is removed. The initial findings are
 quite promising, showing that these children can adapt in the short term
 and improve their walking patterns. These and other similar studies are
 leading researchers down the path to more targeted, rational therapies for
 patients with brain injuries.
     About the Kennedy Krieger Institute
     Internationally recognized for improving the lives of children and
 adolescents with disorders and injuries of the brain and spinal cord, the
 Kennedy Krieger Institute in Baltimore, MD serves more than 13,000
 individuals each year through inpatient and outpatient clinics, home and
 community services and school-based programs. Kennedy Krieger provides a
 wide range of services for children with developmental concerns mild to
 severe, and is home to a team of investigators who are contributing to the
 understanding of how disorders develop while pioneering new interventions
 and earlier diagnosis. For more information on Kennedy Krieger Institute,

SOURCE Kennedy Krieger Institute