1. Dynamic balance and gait impairments in Parkinson’s disease : novel cholinergic patternsNicolaas I. Bohnen, Uroš Marušič, Stiven Roytman, Rebecca Paalanen, Fotini Michalakis, Taylor Brown, Peter J. H. Scott, Giulia Carli, Roger Albin, Prabesh Kanel, 2024, izvirni znanstveni članek Povzetek: The cholinergic system has been implicated in postural deficits, in particular falls, in Parkinson’s disease.
Falls and freezing of gait typically occur during dynamic and challenging balance and gait conditions,
such as when initiating gait, experiencing postural perturbations, or making turns. However, the precise
cholinergic neural substrate underlying dynamic postural and gait changes remains poorly understood.
The aim of this study was to investigate whether brain vesicular acetylcholine transporter binding, as
measured with [18F]-fluoroethoxybenzovesamicolbinding PET, correlates with dynamic gait and balance
impairments in 125 patients with Parkinson’s disease (mean age 66.89±7.71 years) using the abbreviated
Balance Evaluation Systems Test total and its four functional domain sub-scores (anticipatory postural
control, reactive postural control, dynamic gait, and sensory integration). Whole brain false discoverycorrected (P < 0.05) correlations for total abbreviated Balance Evaluation Systems Test scores included
the following bilateral or asymmetric hemispheric regions: gyrus rectus, orbitofrontal cortex, anterior part
of the dorsomedial prefrontal cortex, dorsolateral prefrontal cortex, cingulum, frontotemporal opercula,
insula, fimbria, right temporal pole, mesiotemporal, parietal and visual cortices, caudate nucleus, lateral
and medial geniculate bodies, thalamus, lingual gyrus, cerebellar hemisphere lobule VI, left cerebellar
crus I, superior cerebellar peduncles, flocculus, and nodulus. No significant correlations were found for
the putamen or anteroventral putamen. The four domain-specific sub-scores demonstrated overlapping
cholinergic topography in the metathalamus, fimbria, thalamus proper, and prefrontal cortices but also
showed distinct topographic variations. For example, reactive postural control functions involved the right
flocculus but not the upper brainstem regions. The anterior cingulum associated with reactive postural
control whereas the posterior cingulum correlated with anticipatory control. The spatial extent of
associated cholinergic system changes were least for dynamic gait and sensory orientation functional
domains compared to the anticipatory and reactive postural control functions. We conclude that specific
aspects of dynamic balance and gait deficits in Parkinson’s disease associate with overlapping but also
distinct patterns of cerebral cholinergic system changes in numerous brain regions. Our study also presents
novel evidence of cholinergic topography involved in dynamic balance and gait in Parkinson’s disease
that have not been typically associated with mobility disturbances, such as the right anterior temporal pole,
right anterior part of the dorsomedial prefrontal cortex, gyrus rectus, fimbria, lingual gyrus, flocculus,
nodulus and right cerebellar hemisphere lobules VI and left crus I.
Ključne besede: Parkinson’s disease, dynamic balance, cholinergic, PET
Objavljeno v DiRROS: 30.08.2024; Ogledov: 115; Prenosov: 432
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2. Multisensory mechanisms of gait and balance in Parkinson's disease : an integrative reviewStiven Roytman, Rebecca Paalanen, Giulia Carli, Uroš Marušič, Prabesh Kanel, Teus van Laar, Nicolaas I. Bohnen, 2025, pregledni znanstveni članek Povzetek: Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population. Posture and gait control does not happen automatically, as previously believed, but rather requires continuous involvement of central nervous mechanisms. To effectively exert control over the body, the brain must integrate multiple streams of sensory information, including visual, vestibular, and somatosensory signals. The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work. Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults. Insufficient emphasis, however, has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance. In the present work, we review the contributions of somatosensory, visual, and vestibular modalities, along with their multisensory intersections to gait and balance in older adults and patients with Parkinson's disease. We also review evidence of vestibular contributions to multisensory temporal binding windows, previously shown to be highly pertinent to fall risk in older adults. Lastly, we relate multisensory vestibular mechanisms to potential neural substrates, both at the level of neurobiology (concerning positron emission tomography imaging) and at the level of electrophysiology (concerning electroencephalography). We hope that this integrative review, drawing influence across multiple subdisciplines of neuroscience, paves the way for novel research directions and therapeutic neuromodulatory approaches, to improve the lives of older adults and patients with neurodegenerative diseases.
Ključne besede: aging, gait, balance, encephalography, functional magnetic resonance imaging, multisensory integration
Objavljeno v DiRROS: 17.06.2024; Ogledov: 255; Prenosov: 279
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3. Beta–gamma phase-amplitude coupling as a non-invasive biomarker for Parkinson’s diseas : insights from Electroencephalography studiesTisa Hodnik, Stiven Roytman, Nicolaas I. Bohnen, Uroš Marušič, 2024, pregledni znanstveni članek Povzetek: Phase-amplitude coupling (PAC) describes the interaction of two separate frequencies in which the lower frequency phase acts as a carrier frequency of the higher frequency amplitude. It is a means of carrying integrated streams of information between micro- and macroscale systems in the brain, allowing for coordinated activity of separate brain regions. A beta–gamma PAC increase over the sensorimotor cortex has been observed consistently in people with Parkinson’s disease (PD). Its cause is attributed to neural entrainment in the basal ganglia, caused by pathological degeneration characteristic of PD. Disruptions in this phenomenon in PD patients have been observed in the resting state as well as during movement recordings and have reliably distinguished patients from healthy participants. The changes can be detected non-invasively with the electroencephalogram (EEG). They correspond to the severity of the motor symptoms and the medication status of people with PD. Furthermore, a medication-induced decrease in PAC in PD correlates with the alleviation of motor symptoms measured by assessment scales. A beta–gamma PAC increase has, therefore, been explored as a possible means of quantifying motor pathology in PD. The application of this parameter to closed-loop deep brain stimulation could serve as a self-adaptation measure of such treatment, responding to fluctuations of motor symptom severity in PD. Furthermore, phase-dependent stimulation provides a new precise method for modulating PAC increases in the cortex. This review offers a comprehensive synthesis of the current EEG-based evidence on PAC fluctuations in PD, explores the potential practical utility of this biomarker, and provides recommendations for future research.
Ključne besede: neurodegenerative diseases, Parkinson’s disease, electroencephalography, phase-amplitude coupling
Objavljeno v DiRROS: 21.03.2024; Ogledov: 431; Prenosov: 195
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4. Brain dynamics underlying preserved cycling ability in patients with Parkinson’s disease and freezing of gaitTeja Ličen, Martin Rakuša, Nicolaas I. Bohnen, Paolo Manganotti, Uroš Marušič, 2022, pregledni znanstveni članek Povzetek: Parkinson’s disease (PD) is generally associated with abnormally increased beta band oscillations in the cortico-basal ganglia loop during walking. PD patients with freezing of gait (FOG) exhibit a more distinct, prolonged narrow band of beta oscillations that are locked to the initiation of movement at ∼18 Hz. Upon initiation of cycling movements, this oscillation has been reported to be weaker and rather brief in duration. Due to the suppression of the overall beta band power during cycling and its continuous nature of the movement, cycling is considered to be less demanding for cortical networks compared to walking, including reduced need for sensorimotor processing, and thus unimpaired continuous cycling motion. Furthermore, cycling has been considered one of the most efficient non-pharmacological therapies with an influence on the subthalamic nucleus (STN) beta rhythms implicative of the deep brain stimulation effects. In the current review, we provide an overview of the currently available studies and discuss the underlying mechanism of preserved cycling ability in relation to the FOG in PD patients. The mechanisms are presented in detail using a graphical scheme comparing cortical oscillations during walking and cycling in PD.
Ključne besede: gait, freezing of gait, Parkinson's disease, cycling, cortical oscillations, beta band
Objavljeno v DiRROS: 21.06.2022; Ogledov: 786; Prenosov: 652
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