Summary: A study of Parkinson’s patients reveals neural activity alternates between the right and left sides of the brain as we walk.
Human steps are associated with neural activity that alternates between the left and right sides of the brain, finds a study of Parkinson’s disease patients published in Journal of Neuroscience. The research recommends future investigations address whether alternating deep brain stimulation accordingly may improve gait in movement disorders.
Walking problems reduce quality of life for people with Parkinson’s disease. Medication or continuous deep brain stimulation are used to alleviate these symptoms, but some patients do not respond to these treatments.
To better understand how brain activity changes throughout the stepping cycle, Petra Fischer, Huiling Tan and colleagues studied Parkinson’s patients who have received deep brain stimulation surgery. This enabled the researchers to record brain activity from electrodes implanted in the subthalamic nucleus (STN) while participants stepped in place along with a cartoon man in a video.
The researchers found that activity in the 20-30 Hz (beta) range alternated between the left and right STN when the opposite foot touched the ground and the other foot was to be raised. The introduction of a metronome synchronized to the cartoon steps improved participants’ accuracy and enhanced their STN beta activity accordingly.
Funding: Medical Research Council, National Institute of Health Research, Wellcome Trust, European Union, Ministry of Science and Technology in Taiwan, Parkinson Appeal UK, Monument Trust funded this study.
Source: David Barnstone – SfN
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is credited to Fischer et al., JNeurosci (2018).
Original Research: Abstract for “Alternating modulation of subthalamic nucleus beta oscillations during stepping” by Petra Fischer, Chiung Chu Chen, Ya Ju Chang, Chien-Hung Yeh, Alek Pogosyan, Damian M. Herz, Binith Cheeran, Alexander L. Green, Tipu Z. Aziz, Jonathan Hyam, Simon Little, Thomas Foltynie, Patricia Limousin, Ludvic Zrinzo, Harutomo Hasegawa, Michael Samuel, Keyoumars Ashkan, Peter Brown and Huiling Tan in Journal of Neuroscience. Published May 14 2018.
Alternating modulation of subthalamic nucleus beta oscillations during stepping
Gait disturbances in Parkinson’s disease are commonly refractory to current treatment options and majorly impair patient’s quality of life. Auditory cues facilitate gait and prevent motor blocks. We investigated how neural dynamics in the human subthalamic nucleus of Parkinsons’s disease patients (14 male, 2 female) vary during stepping and whether rhythmic auditory cues enhance the observed modulation. Oscillations in the beta band were suppressed after ipsilateral heel strikes, when the contralateral foot had to be raised, and re-appeared after contralateral heel strikes, when the contralateral foot rested on the floor. The timing of this 20-30 Hz beta modulation was clearly distinct between the left and right subthalamic nucleus, and was alternating within each stepping cycle. This modulation was similar, whether stepping movements were made while sitting, standing, or during gait, confirming the utility of the stepping in place paradigm. During stepping in place beta modulation increased with auditory cues that assisted patients in timing their steps more regularly. Our results suggest a link between the degree of power modulation within high beta frequency bands and stepping performance. These findings raise the possibility that alternating deep brain stimulation patterns may be superior to constant stimulation for improving Parkinsonian gait.
Gait disturbances in Parkinson’s disease majorly reduce patients’ quality of life and are often refractory to current treatment options. We investigated how neural activity in the subthalamic nucleus of patients who received deep brain stimulation surgery covaries with the stepping cycle. 20-30Hz beta activity was modulated relative to each step, alternating between the left and right STN. The stepping performance of patients improved when auditory cues were provided, which went along with enhanced beta modulation. This raises the possibility that alternating stimulation patterns may also enhance beta modulation and may be more beneficial for gait control than continuous stimulation, which needs to be tested in future studies.