TY  - JOUR
A1  - Pötter-Nerger, Monika
A1  - Reese, Rene
A1  - Steigerwald, Frank
A1  - Heiden, Jan Arne
A1  - Herzog, Jan
A1  - Moll, Christian K. E.
A1  - Hamel, Wolfgang
A1  - Ramirez-Pasos, Uri
A1  - Falk, Daniela
A1  - Mehdorn, Maximilian
A1  - Gerloff, Christian
A1  - Deuschl, Günther
A1  - Volkmann, Jens
T1  - Movement-Related Activity of Human Subthalamic Neurons during a Reach-to-Grasp Task
JF  - Frontiers in Human Neuroscience
N2  - The aim of the study was to record movement-related single unit activity (SUA) in the human subthalamic nucleus (STN) during a standardized motor task of the upper limb. We performed microrecordings from the motor region of the human STN and registered kinematic data in 12 patients with Parkinson’s disease (PD) undergoing deep brain stimulation surgery (seven women, mean age 62.0 ± 4.7 years) while they intraoperatively performed visually cued reach-to-grasp movements using a grip device. SUA was analyzed offline in relation to different aspects of the movement (attention, start of the movement, movement velocity, button press) in terms of firing frequency, firing pattern, and oscillation. During the reach-to-grasp movement, 75/114 isolated subthalamic neurons exhibited movement-related activity changes. The largest proportion of single units showed modulation of firing frequency during several phases of the reach and grasp (polymodal neurons, 45/114), particularly an increase of firing rate during the reaching phase of the movement, which often correlated with movement velocity. The firing pattern (bursting, irregular, or tonic) remained unchanged during movement compared to rest. Oscillatory single unit firing activity (predominantly in the theta and beta frequency) decreased with movement onset, irrespective of oscillation frequency. This study shows for the first time specific, task-related, SUA changes during the reach-to-grasp movement in humans.
KW  - subthalamic nucleus
KW  - deep brain stimulation
KW  - Parkinson’s disease
KW  - neurophysiology
KW  - beta oscillation
KW  - reach-to-grasp movement
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170361
VL  - 11
IS  - 436
ER  - 
TY  - JOUR
A1  - Bolzoni, Francesco
A1  - Esposti, Roberto
A1  - Marchese, Silvia M.
A1  - Pozzi, Nicoló G.
A1  - Ramirez-Pasos, Uri E.
A1  - Isaias, Ioannis U.
A1  - Cavallari, Paolo
T1  - Disrupt of intra-limb APA pattern in parkinsonian patients performing index-finger flexion
JF  - Frontiers in Physiology
N2  - Voluntary movements induce postural perturbations which are counteracted by anticipatory postural adjustments (APAs). These actions are known to build up long fixation chains toward available support points (inter-limb APAs), so as to grant whole body equilibrium. Moreover, recent studies highlighted that APAs also build-up short fixation chains, within the same limb where a distal segment is moved (intra-limb APAs), aimed at stabilizing the proximal segments. The neural structures generating intra-limb APAs still need investigations; the present study aims to compare focal movement kinematics and intra-limb APA latencies and pattern between healthy subjects and parkinsonian patients, assuming the latter as a model of basal ganglia dysfunction. Intra-limb APAs that stabilize the arm when the index-finger is briskly flexed were recorded in 13 parkinsonian patients and in 10 age-matched healthy subjects. Index-finger movement was smaller in parkinsonian patients vs. healthy subjects (p = 0.01) and more delayed with respect to the onset of the prime mover flexor digitorum superficialis (FDS, p < 0.0001). In agreement with the literature, in all healthy subjects the FDS activation was preceded by an inhibitory intra-limb APA in biceps brachii (BB) and anterior deltoid (AD), and almost simultaneous to an excitatory intra-limb APA in triceps brachii (TB). In parkinsonian patients, no significant differences were found for TB and AD intra-limb APA timings, however only four patients showed an inhibitory intra-limb APA in BB, while other four did not show any BB intra-limb APAs and five actually developed a BB excitation. The frequency of occurrence of normal sign, lacking, and inverted BB APAs was different in healthy vs. parkinsonian participants (p = 0.0016). The observed alterations in index-finger kinematics and intra-limb APA pattern in parkinsonian patients suggest that basal ganglia, in addition to shaping the focal movement, may also contribute to intra-limb APA control.
KW  - intra-limb anticipatory postural adjustments
KW  - Parkinson disease
KW  - basal ganglia
KW  - motor control
KW  - human
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-369245
SN  - 1664-042X
VL  - 9
ER  -