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EPV 15. Reward processing modulates beta activity in local field potentials of the subthalamic nucleus
Abstracts / Clinical Neurophysiology 127 (2016) e210–e303
more importantly, the PREP-recordings are able to depict quantitatively the CPM-effect electrophysiologically in an objective way. References Yarnitsky D, Bouhassira D, Drewes AM, Fillingim RB, Granot M, Hansson P, Landau R, Marchand S, Matre D, Nilsen KB, Stubhaug A, Treede RD, Wilder-Smith OH. Recommendations on practice of conditioned pain modulation (CPM) testing. Eur J Pain 2015;19(6):805–6. Katsarava Z, Ayzenberg I, Sack F, Limmroth V, Diener HC, Kaube H. A novel method of eliciting pain-related potentials by transcutaneous electrical stimulation. Headache 2006;46:1511–7. doi:10.1016/j.clinph.2016.05.033
EPV 14. Non-invasive single-trial detection of human population spike responses in somatosensory evoked potentials in a realistic clinical setting—G. Waterstraat a,*, G. Curio a,b (a Charité – University Medicine Berlin, Neurophysics Group, Department of Neurology, Berlin, Germany , b Bernstein Center for Computational Neuroscience, Berlin, Germany) ⇑
Corresponding author.
Introduction: High-frequency EEG oscillations (600 Hz; HFO) evoked by median nerve stimulation and recorded above the human somatosensory cortex are non-invasive correlates of cortical population spikes. Recently, it was shown that spatiotemporal filtering and multivariate classification enables single-trial HFO detection using 29-channel low-impedance (<1 kXÞ low-noise EEG in an electromagnetically shielded recording chamber. It is an open question, whether this can be achieved in a realistic clinical setting. Methods: With a custom-built CE-certified low-noise EEG amplifier, median nerve SEPs were recorded in 10 healthy subjects using 8 electrodes (impedances 1 kXÞ in a standard unshielded hospital environment. After band-pass filtering (500–900 Hz), a subset of the trials (N = 2000) was used to train the two-step single-trial HFO detector, which is composed of spatiotemporal filter optimization and nonlinear classification. The performance of the algorithm was assessed using an independent set of additional trials (N = 5200). Results: In the present group of 10 subjects, on average the algorithm detected evoked HFOs in 64.9% of the single trials in the correct latency window (around 20 ms) with a positive predictive value (PPV) of 61.9%. Notably, in several subjects with a higher signal-plus-noise-to-noise ratio (SNNR), detection rate (DR) and PPV were above 80% (peak values: SNNR = 2.0, DR = 95.2%, PPV = 98.5%). Conclusions: A non-invasive single-trial detection of human population spike responses in somatosensory evoked potentials can be achieved also in a realistic unshielded clinical setting. The increase in sensitivity brought about by combined hardware and algorithmic improvements enables the analysis of single-trial variability and might be extended also to pathological components, such as the non-invasive detection of epileptic neocortical high-frequency oscillations. doi:10.1016/j.clinph.2016.05.034
EPV 15. Reward processing modulates beta activity in local field potentials of the subthalamic nucleus—H. Schroll a,b,c,*, A. Horn c, J. Runge d, G.-H. Schneider e, J.K. Krauss d, F.H. Hamker a, A.A. Kühn c (a Computer Science, Technische Universität Chemnitz, Chemnitz, Germany , b Psychology, Humboldt-Universität zu
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Berlin, Berlin, Germany , c Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany, d Neurosurgery, Medizinische Hochschule Hannover, Hannover, Germany, e Neurosurgery, Charité – Universitätsmedizin Berlin, Berlin, Germany) ⇑
Corresponding author.
In Parkinson’s disease, dopamine loss results in an increase in beta oscillations in the subthalamic nucleus that correlates well with the severity of patients’ akinetic-rigid symptoms (Kühn et al., Experimental Neurology, 2009). There is, however, yet incomplete evidence on the functions of beta activity in the healthy brain. Given that dopamine plays an important role in the processing of rewards (Schultz et al., Science, 1997), we investigated whether beta activity might be related to reward processing. We recorded local field potentials in patients with Parkinson’s disease, while these patients performed a computer-based reinforcement learning task. In each trial, patients had to choose one out of three possible joystick movements (left, right, up). Afterwards, a reward signal (number between 0 and 10) was presented. Each movement direction was associated with a reward probability curve, where curves differed in means. After intervals of approximately 20 trials, reward probability curves were randomly reassigned between joystick movements. Patients were asked to choose joystick movements such as to maximize reward points. Event-related modulation in STN oscillatory activity was analyzed with respect to reward presentation and movement execution and correlated with the magnitudes of observed rewards across trials. We found a significant positive correlation (rho = 0.23, p = 0.006) between reward magnitudes and beta activity during the time interval of reward presentation. Moreover, we found a significant negative correlation (rho = 0.20, p = 0.045) between reward magnitudes and alpha activity during the movements following the rewards (i.e., the subsequent-trial movements). These results suggest a role of beta activity in the processing of rewards, while alpha activity might be related to the reward-based adaptation of motor responses. doi:10.1016/j.clinph.2016.05.035
EPV 16. Spatial orientation deficit in a rat model of acute bilateral vestibulopathy—A. Zwergal a,b,*, E. Eilles b, L. Günther b, R. Beck b, M. Dieterich a,b, T. Brandt c,b (a Ludwig-Maximilians-Universität München, Neurologie, München, Germany , b LudwigMaximilians-Universität München, Deutsches Schwindel- und Gleichgewichtszentrum (DSGZ), München, Germany, c LudwigMaximilians-Universität München, Klinische Neurowissenschaften, München, Germany) ⇑
Corresponding author.
Background and aim: Characterisation of the spatial orientation and locomotion behaviour after bilateral vestibular labyrinthectomy in the rat. Methods: Ten Sprague-Dawley rats underwent a bilateral labyrinthectomy (BL) by transtympanic injection of bupivacaine and arsenilate, 10 rats received a bilateral middle-ear injection of saline (sham) as a control group. Behavioural testing was performed 1 day before and at days 1, 2, 3, 7, 15, 30 and 60 after BL/sham injection as follows: (1) analysis of spatial exploration behaviour in a square open field by the Noldus EthoVision System; (2) quantitative analysis of locomotion pattern by the Noldus CatWalk System.
more importantly, the PREP-recordings are able to depict quantitatively the CPM-effect electrophysiologically in an objective way. References Yarnitsky D, Bouhassira D, Drewes AM, Fillingim RB, Granot M, Hansson P, Landau R, Marchand S, Matre D, Nilsen KB, Stubhaug A, Treede RD, Wilder-Smith OH. Recommendations on practice of conditioned pain modulation (CPM) testing. Eur J Pain 2015;19(6):805–6. Katsarava Z, Ayzenberg I, Sack F, Limmroth V, Diener HC, Kaube H. A novel method of eliciting pain-related potentials by transcutaneous electrical stimulation. Headache 2006;46:1511–7. doi:10.1016/j.clinph.2016.05.033
EPV 14. Non-invasive single-trial detection of human population spike responses in somatosensory evoked potentials in a realistic clinical setting—G. Waterstraat a,*, G. Curio a,b (a Charité – University Medicine Berlin, Neurophysics Group, Department of Neurology, Berlin, Germany , b Bernstein Center for Computational Neuroscience, Berlin, Germany) ⇑
Corresponding author.
Introduction: High-frequency EEG oscillations (600 Hz; HFO) evoked by median nerve stimulation and recorded above the human somatosensory cortex are non-invasive correlates of cortical population spikes. Recently, it was shown that spatiotemporal filtering and multivariate classification enables single-trial HFO detection using 29-channel low-impedance (<1 kXÞ low-noise EEG in an electromagnetically shielded recording chamber. It is an open question, whether this can be achieved in a realistic clinical setting. Methods: With a custom-built CE-certified low-noise EEG amplifier, median nerve SEPs were recorded in 10 healthy subjects using 8 electrodes (impedances 1 kXÞ in a standard unshielded hospital environment. After band-pass filtering (500–900 Hz), a subset of the trials (N = 2000) was used to train the two-step single-trial HFO detector, which is composed of spatiotemporal filter optimization and nonlinear classification. The performance of the algorithm was assessed using an independent set of additional trials (N = 5200). Results: In the present group of 10 subjects, on average the algorithm detected evoked HFOs in 64.9% of the single trials in the correct latency window (around 20 ms) with a positive predictive value (PPV) of 61.9%. Notably, in several subjects with a higher signal-plus-noise-to-noise ratio (SNNR), detection rate (DR) and PPV were above 80% (peak values: SNNR = 2.0, DR = 95.2%, PPV = 98.5%). Conclusions: A non-invasive single-trial detection of human population spike responses in somatosensory evoked potentials can be achieved also in a realistic unshielded clinical setting. The increase in sensitivity brought about by combined hardware and algorithmic improvements enables the analysis of single-trial variability and might be extended also to pathological components, such as the non-invasive detection of epileptic neocortical high-frequency oscillations. doi:10.1016/j.clinph.2016.05.034
EPV 15. Reward processing modulates beta activity in local field potentials of the subthalamic nucleus—H. Schroll a,b,c,*, A. Horn c, J. Runge d, G.-H. Schneider e, J.K. Krauss d, F.H. Hamker a, A.A. Kühn c (a Computer Science, Technische Universität Chemnitz, Chemnitz, Germany , b Psychology, Humboldt-Universität zu
e219
Berlin, Berlin, Germany , c Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany, d Neurosurgery, Medizinische Hochschule Hannover, Hannover, Germany, e Neurosurgery, Charité – Universitätsmedizin Berlin, Berlin, Germany) ⇑
Corresponding author.
In Parkinson’s disease, dopamine loss results in an increase in beta oscillations in the subthalamic nucleus that correlates well with the severity of patients’ akinetic-rigid symptoms (Kühn et al., Experimental Neurology, 2009). There is, however, yet incomplete evidence on the functions of beta activity in the healthy brain. Given that dopamine plays an important role in the processing of rewards (Schultz et al., Science, 1997), we investigated whether beta activity might be related to reward processing. We recorded local field potentials in patients with Parkinson’s disease, while these patients performed a computer-based reinforcement learning task. In each trial, patients had to choose one out of three possible joystick movements (left, right, up). Afterwards, a reward signal (number between 0 and 10) was presented. Each movement direction was associated with a reward probability curve, where curves differed in means. After intervals of approximately 20 trials, reward probability curves were randomly reassigned between joystick movements. Patients were asked to choose joystick movements such as to maximize reward points. Event-related modulation in STN oscillatory activity was analyzed with respect to reward presentation and movement execution and correlated with the magnitudes of observed rewards across trials. We found a significant positive correlation (rho = 0.23, p = 0.006) between reward magnitudes and beta activity during the time interval of reward presentation. Moreover, we found a significant negative correlation (rho = 0.20, p = 0.045) between reward magnitudes and alpha activity during the movements following the rewards (i.e., the subsequent-trial movements). These results suggest a role of beta activity in the processing of rewards, while alpha activity might be related to the reward-based adaptation of motor responses. doi:10.1016/j.clinph.2016.05.035
EPV 16. Spatial orientation deficit in a rat model of acute bilateral vestibulopathy—A. Zwergal a,b,*, E. Eilles b, L. Günther b, R. Beck b, M. Dieterich a,b, T. Brandt c,b (a Ludwig-Maximilians-Universität München, Neurologie, München, Germany , b LudwigMaximilians-Universität München, Deutsches Schwindel- und Gleichgewichtszentrum (DSGZ), München, Germany, c LudwigMaximilians-Universität München, Klinische Neurowissenschaften, München, Germany) ⇑
Corresponding author.
Background and aim: Characterisation of the spatial orientation and locomotion behaviour after bilateral vestibular labyrinthectomy in the rat. Methods: Ten Sprague-Dawley rats underwent a bilateral labyrinthectomy (BL) by transtympanic injection of bupivacaine and arsenilate, 10 rats received a bilateral middle-ear injection of saline (sham) as a control group. Behavioural testing was performed 1 day before and at days 1, 2, 3, 7, 15, 30 and 60 after BL/sham injection as follows: (1) analysis of spatial exploration behaviour in a square open field by the Noldus EthoVision System; (2) quantitative analysis of locomotion pattern by the Noldus CatWalk System.