JNNP: Regulation of exercise environment on spike activity in the substantia nigra reticularis in patients with Parkinson's disease

Parkinson's disease (PD) is a movement disorder characterized by resting tremor, bradykinesia, limb stiffness, and postural instability
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Motor manifestations in Parkinson's disease arise from degeneration of dopamine (DA)-secreting neurons in the substantia nigra pars compacta (SNc), resulting in dysregulation of SNc targets, including the substantia nigra reticulum (SNr) through direct and indirect projections

It has been shown that sensory cues can significantly improve walking speed and balance in patients with Parkinson's disease; however, little is known about the neural basis of this environmental dependence

This article was published in the Journal of Neurology, Neurosurgery & Psychiatry .

Signal-to-noise activity was recorded when subjects performed suggestive directional movements to auditory stimuli in staggered 'patterned' and 'unpatterned' contexts
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SNr localization was independently confirmed by expert intraoperative assessment and post-hoc imaging-based reconstruction

Signal-to-noise activity was recorded when subjects performed suggestive directional movements to auditory stimuli in staggered 'patterned' and 'unpatterned' contexts

Post-hoc STN electrodes and reconstruction of SNR recordings

As predicted, motor performance is now improved in the patterned environment, reflected in improved reaction speed and accuracy compared to the patternless environment
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These behavioral differences were associated with increased responsiveness of SNr neurons, that is, greater changes in activity compared to baseline in a patterned environment

As predicted, motor performance is now improved in the patterned environment, reflected in improved reaction speed and accuracy compared to the patternless environment

This study examined whether signal-to-noise activity in Parkinson's disease patients is associated with changes in motor performance mediated by different environments

Targets of SNr neuronal subtypes
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Clustering of SNr neurons (n ​​= 33) based on waveform features revealed two distinct neuronal populations

It was investigated whether background, response direction or response outcome affects SNr activity in PD patients
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Firing rate-based analysis revealed context-modulated SNr activity (n = 33 neurons), particularly in events related to sensory processing, motor preparation, and motor initiation

This suggests that context-influenced cognitive processes extend beyond those related only to active motor control

This explanation is supported by experimental observations that SNr is more responsive in the patterned environment, although the enhanced responsiveness may reflect BG output in the patterned environment compared to the patternless environment at baseline were recruited more, and equivalent neurodegeneration occurred in the associated circuits

TekriwalA ,FelsenG ,OjemannSG TekriwalATekriwal FelsenGFelsen OjemannSGOjemann, et alMotor context modulates substantia nigra pars reticulata spike activity in patients with Parkinson's diseaseJournal of Neurology, Neurosurgery & PsychiatryPublished Online First:22 February 2022.
 Published Online First: doi:  10.
1136/jnnp-2021-326962doi:

 

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