@article{PalmisanoBrandtVissanietal.2020, author = {Palmisano, Chiara and Brandt, Gregor and Vissani, Matteo and Pozzi, Nicol{\´o} G. and Canessa, Andrea and Brumberg, Joachim and Marotta, Giorgio and Volkmann, Jens and Mazzoni, Alberto and Pezzoli, Gianni and Frigo, Carlo A. and Isaias, Ioannis U.}, title = {Gait Initiation in Parkinson's Disease: Impact of Dopamine Depletion and Initial Stance Condition}, series = {Frontiers in Bioengineering and Biotechnology}, volume = {8}, journal = {Frontiers in Bioengineering and Biotechnology}, issn = {2296-4185}, doi = {10.3389/fbioe.2020.00137}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200801}, year = {2020}, abstract = {Postural instability, in particular at gait initiation (GI), and resulting falls are a major determinant of poor quality of life in subjects with Parkinson's disease (PD). Still, the contribution of the basal ganglia and dopamine on the feedforward postural control associated with this motor task is poorly known. In addition, the influence of anthropometric measures (AM) and initial stance condition on GI has never been consistently assessed. The biomechanical resultants of anticipatory postural adjustments contributing to GI [imbalance (IMB), unloading (UNL), and stepping phase) were studied in 26 unmedicated subjects with idiopathic PD and in 27 healthy subjects. A subset of 13 patients was analyzed under standardized medication conditions and the striatal dopaminergic innervation was studied in 22 patients using FP-CIT and SPECT. People with PD showed a significant reduction in center of pressure (CoP) displacement and velocity during the IMB phase, reduced first step length and velocity, and decreased velocity and acceleration of the center of mass (CoM) at toe off of the stance foot. All these measurements correlated with the dopaminergic innervation of the putamen and substantially improved with levodopa. These results were not influenced by anthropometric parameters or by the initial stance condition. In contrast, most of the measurements of the UNL phase were influenced by the foot placement and did not correlate with putaminal dopaminergic innervation. Our results suggest a significant role of dopamine and the putamen particularly in the elaboration of the IMB phase of anticipatory postural adjustments and in the execution of the first step. The basal ganglia circuitry may contribute to defining the optimal referent body configuration for a proper initiation of gait and possibly gait adaptation to the environment.}, language = {en} } @article{IsaiasVolkmannMarzeganetal.2012, author = {Isaias, Ioannis U. and Volkmann, Jens and Marzegan, Alberto and Marotta, Giorgio and Cavallari, Paolo and Pezzoli, Gianni}, title = {The Influence of Dopaminergic Striatal Innervation on Upper Limb Locomotor Synergies}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {12}, doi = {10.1371/journal.pone.0051464}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133976}, pages = {e51464}, year = {2012}, abstract = {To determine the role of striatal dopaminergic innervation on upper limb synergies during walking, we measured arm kinematics in 13 subjects with Parkinson disease. Patients were recruited according to several inclusion criteria to represent the best possible in vivo model of dopaminergic denervation. Of relevance, we included only subjects with normal spatio-temporal parameters of the stride and gait speed to avoid an impairment of upper limbs locomotor synergies as a consequence of gait impairment per se. Dopaminergic innervation of the striatum was measured by FP-CIT and SPECT. All patients showed a reduction of gait-associated arms movement. No linear correlation was found between arm ROM reduction and contralateral dopaminergic putaminal innervation loss. Still, a partition analysis revealed a 80\% chance of reduced arm ROM when putaminal dopamine content loss was >47\%. A significant correlation was described between the asymmetry indices of the swinging of the two arms and dopaminergic striatal innervation. When arm ROM was reduced, we found a positive correlation between upper-lower limb phase shift modulation ( at different gait velocities) and striatal dopaminergic innervation. These findings are preliminary evidence that dopaminergic striatal tone plays a modulatory role in upper-limb locomotor synergies and upper-lower limb coupling while walking at different velocities.}, language = {en} } @article{IsaiasMarzeganPezzolietal.2012, author = {Isaias, Ioannis U. and Marzegan, Alberto and Pezzoli, Gianni and Marotta, Giorgio and Canesi, Margherita and Biella, Gabriele E. M. and Volkmann, Jens and Cavallari, Paolo}, title = {A role for locus coeruleus in Parkinson tremor}, series = {Frontiers in Human Neuroscience}, volume = {5}, journal = {Frontiers in Human Neuroscience}, number = {179}, doi = {10.3389/fnhum.2011.00179}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133955}, year = {2012}, abstract = {We analyzed rest tremor, one of the etiologically most elusive hallmarks of Parkinson disease(PD), in 12 consecutive PD patients during a specific task activating the locus coeruleus (LC) to investigate a putative role of noradrenaline (NA) in tremor generation and suppression. Clinical diagnosis was confirmed in all subjects by reduced dopamine reuptake transporter (DAT) binding values investigated by single photon computed tomography imaging (SPECT) with [\(^{123}\)I] N-\(\omega\)-fluoropropyl-2 \(\beta\)-carbomethoxy-3 \(\beta\)-(4-iodophenyl) tropane (FP-CIT). The intensity of tremor (i.e., the power of Electromyography [EMG] signals), but not its frequency, significantly increased during the task. In six subjects, tremor appeared selectively during the task. In a second part of the study, we retrospectively reviewed SPECT with FP-CIT data and confirmed the lack of correlation between dopaminergic loss and tremor by comparing DAT binding values of 82 PD subjects with bilateral tremor (n = 27), unilateral tremor (n = 22), and no tremor (n = 33). This study suggests a role of the LC in Parkinson tremor.}, language = {en} } @article{BiehlDreslerReifetal.2011, author = {Biehl, Stefanie C. and Dresler, Thomas and Reif, Andreas and Scheuerpflug, Peter and Deckert, J{\"u}rgen and Herrmann, Martin J.}, title = {Dopamine Transporter (DAT1) and Dopamine Receptor D4 (DRD4) Genotypes Differentially Impact on Electrophysiological Correlates of Error Processing}, series = {PLoS One}, volume = {6}, journal = {PLoS One}, number = {12}, doi = {10.1371/journal.pone.0028396}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137930}, pages = {e28396}, year = {2011}, abstract = {Recent studies as well as theoretical models of error processing assign fundamental importance to the brain's dopaminergic system. Research about how the electrophysiological correlates of error processing—the error-related negativity (ERN) and the error positivity (Pe)—are influenced by variations of common dopaminergic genes, however, is still relatively scarce. In the present study, we therefore investigated whether polymorphisms in the DAT1 gene and in the DRD4 gene, respectively, lead to interindividual differences in these error processing correlates. One hundred sixty participants completed a version of the Eriksen Flanker Task while a 26-channel EEG was recorded. The task was slightly modified in order to increase error rates. During data analysis, participants were split into two groups depending on their DAT1 and their DRD4 genotypes, respectively. ERN and Pe amplitudes after correct responses and after errors as well as difference amplitudes between errors and correct responses were analyzed. We found a differential effect of DAT1 genotype on the Pe difference amplitude but not on the ERN difference amplitude, while the reverse was true for DRD4 genotype. These findings are in line with predictions from theoretical models of dopaminergic transmission in the brain. They furthermore tie results from clinical investigations of disorders impacting on the dopamine system to genetic variations known to be at-risk genotypes.}, language = {en} } @article{BahmerGupta2018, author = {Bahmer, Andreas and Gupta, Daya Shankar}, title = {Role of Oscillations in Auditory Temporal Processing: A General Model for Temporal Processing of Sensory Information in the Brain?}, series = {Frontiers in Neuroscience}, volume = {12}, journal = {Frontiers in Neuroscience}, number = {793}, issn = {1662-453X}, doi = {10.3389/fnins.2018.00793}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196087}, year = {2018}, abstract = {We review the role of oscillations in the brain and in the auditory system showing that the ability of humans to distinguish changes in pitch can be explained as a precise analysis of temporal information in auditory signals by neural oscillations. The connections between auditory brain stem chopper neurons construct neural oscillators, which discharge spikes at various constant intervals that are integer multiples of 0.4 ms, contributing to the temporal processing of auditory cochlear output. This is subsequently spatially mapped in the inferior colliculus. Electrophysiological measurements of auditory chopper neurons in different species show oscillations with periods which are integer multiples of 0.4 ms. The constant intervals of 0.4 ms can be attributed to the smallest synaptic delay between interconnected simulated chopper neurons. We also note the patterns of similarities between microcircuits in the brain stem and other parts of the brain (e.g., the pallidum, reticular formation, locus coeruleus, oculomotor nuclei, limbic system, amygdala, hippocampus, basal ganglia and substantia nigra), dedicated to the processing of temporal information. Similarities in microcircuits across the brain reflect the importance of one of the key mechanisms in the information processing in the brain, namely the temporal coupling of different neural events via coincidence detection.}, language = {en} }