29th International Congress of Clinical Neurophysiology S321 P36-15 Improved bereitschaftspotential (BP) in Parkinson’s disease (PD) by means of neuro-feedback (NFB) training of slow cortical potentials (SCPs) T. Fumuro 1 , M. Matsuhashi 2 , T. Mitsueda 1,3 , M. Inouchi 1 , R. Matsumoto 1 , J. Kawamata 1 , H. Inoue 1 , R. Takahashi 1 , A. Ikeda 1 1 Department of Neurology, Kyoto University Hospital, Kyoto, Japan, 2 Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan, 3 Department of Neurology, Otsu Red Cross Hospital, Shiga, Japan Objective: Early component of BP (early BP) was smaller in PD patients than in healthy volunteers whereas its late component (late BP) rather increased. We previously reported that once young healthy volunteers well learned to control their SCPs by means of NFB, they could increase early BP amplitude during self-regulated negative SCPs performance (Fumuro et al., 2006, in Japanese). We investigated the effects of self- regulation of SCPs on BP amplitude in PD patients and aged healthy volunteers. Methods: 7 PD patients and 9 healthy volunteers were recruited. 5 electrodes were fixed on the scalp (C3, C1, Cz, C2 and C4). BP was firstly recorded for self-paced, button-press by the right thumb about every 10 sec (BP1). It was followed by NFB training where subjects trained himself for self-regulation of SCPs of Cz for 20 to 50 min. The 2nd BP was recorded while self-regulated negative SCPs was performed (BP2). The whole set was done in one day and was repeated 2 to 4 times on different days. BP1 and BP2 were compared between the two groups depending on the degree of NFB performance (good trials vs poor trials). Results: Good trial sessions had larger early BP in BP2 than that in BP1 whereas poor trial sessions had smaller early BP in BP2 than that in BP1. In contrast, late BP showed no difference between BP1 and BP2 regardless the degree of NFB performance. It was commonly seen in both PD patients and healthy volunteers. Conclusions: Good NFB performance of negativation could increase EPSP of pyramidal cells for early BP generation in PD patients and healthy volunteers. Significance: NFB could enhance the excitability of cortices related to voluntary movement preparation, and a further investigation will be warranted for improvement of motor function of PD in relation to the BP enhancement. P36-16 Event related desynchronization of subthalamic nucleus activities prior to volitional movement termination in patients with Parkinson disease C.-H. Tsai 1,4 , T.-F. Chien 2 , H.-Y. Lai 2 , Y.-T. Hsu 1 , Y.-Y. Chen 2 , S.-M. Chiou 3 1 Department of Neurology, China Medical University Hospital, Taiwan, 2 Department of Electrical Engineering, National Chiao-Tung University, Taiwan, 3 Department of Neurosurgery, China Medical University Hospital, Taiwan, 4 Graduate Institute of Neural and Cognitive Sciences, Taiwan Objective: The subthalamic nucleus (STN) activities play an important role for the cortical-basal ganglia circuitry, which were associated with the feedforward organization of the volitional movement initiation. How STN implicates in movement termination is uncertain. The current study investigates the pre-termination activities of the STN during phasic and tonic wrist extension movements in patients with advanced Parkinson disease (PD) after deep brain stimulation. Methods: Ten patients with Parkinson disease (five females; mean±SEM age 63.2±9.7 years, disease duration 5.25±2.1 years) were recruited for the study on the 4th day after deep brain stimulation. The automatic burst detection method was adopted to determine the initiation and termination points of volitional EMG burst. The local field potentials (LFPs) of STN were analyzed by time frequency (TF) analysis. The TF analysis presented response both in time and frequency domain. The algorithm used in this experiment was power spectra with 1024 frequency resolutions. Spectra were estimated by calculating median across sections and block sections were shifted by stationary data points until the whole sequence had been analyzed. Results: Averaged movement duration is 0.96±0.40 sec in the phasic movement and 9.19±3.63 sec in the tonic movement. The results show event-related desynchronization (ERD) at the frequencies from 10 to 40Hz. The decrease of power percentage commenced earlier, at the 2-second point prior to movement termination, and greater in phasic movement as compared with the tonic one. The main difference of power percentage between the 2 groups is over 50% from 0.8 second to 0 second before movement termination. Conclusion: The findings implicate that the 10 to 40 Hz local field potentials (LFPs) of STN plays a crucial feedforward role in movement termination and the role may be modulated by different types of volitional movements. P36-17 Cerebral preparation of natural movements: an EEG study E. Houdayer 1 , R. Kayal 1 , J. Chu 1 , M. Hallett 1 1 Human Motor Control Section, NINDS, NIH, Bethesda, USA Objective: To investigate whether cerebral activity related to natural movements, without any previous instruction, is similar to activity observed before self-paced, ‘instructed’ movements. Methods: Twelve healthy volunteers were recruited. Subjects were told that the purpose of the study was to record natural flow of brain and muscles. They stayed seated in an armchair for one hour and received no instructions except not to fall asleep. They were not allowed to use any external device to entertain themselves. Three subjects were also told to perform self-paced right wrist extensions. Electroencephalographic (EEG) activity was recorded with 32 scalp electrodes. Electromyographic (EMG) activity of several arms and legs muscles was recorded bilaterally. Bereitschaftspotential (BP) as well as mu and beta event-related desynchronizations (ERD) were calculated off- line, in relation to movement onset. Results: Two subjects did not move. The ten others moved arms and legs freely. One had no BP or ERD preceding his movements. For the 9 others, a BP and mu or beta ERD preceded the natural movements. They were located over sensorimotor areas, bilaterally and maximal over medial electrodes (most of movements were bilateral). BP and ERD onset was similar to the ‘instructed’ condition. However, BPs preceding natural movements were spread in more frontal areas compared to the instructed condition in which they were more parietal. Conclusions: Our results show that ‘natural’ movements are preceded by BP and ERD similar to the ones observed in ‘instructed’ conditions. Interestingly, the latencies of BP or ERD in ‘natural’ or ‘instructed’ conditions were very similar. This result confirms that the brain activity starts to prepare the motor plan far in advance compared to the movement onset. The difference of localization might be due to a difference in motor planning, since the instructed movements might have been generated more automatically. P36-18 Scalp topography of sniffing-related cortical potentials B. Koritnik 1 , D. Jeran 1 , I. Zidar 1 , A. Belic 2 , M. Korosec 1 , J. Zidar 1 1 Institute of Clinical Neurophysiology, University Medical Centre Ljubljana, Ljubljana, Slovenia, 2 Faculty of Electrical Engineering, University of Ljubljana, Slovenia Objective: A possible way to study the neural mechanisms for the control of voluntary breathing is through respiratory manoeuvres such as sniffing. Cortical potentials associated with voluntary movement can be recorded during self-paced inspiratory manoeuvres. Our aim was to describe the scalp distribution of sniffing-related cortical potentials (SRCP) and to distinguish various subcomponents of SRCP. Methods: Ten healthy subjects participated in the study. They were performing self-paced voluntary sniffs with submaximal intensity. EEG was recorded using a 32-electrode cap. Nasal pressure changes were used to average the EEG signal. Epochs starting 2.5 s before and ending 1 s after the sniff onset were analysed. Principal component analysis (PCA) was performed in three different time intervals, corresponding to the Bereitschaftspotential (BP; 1.5 to 0.5 s), negative slope (NS; 0.5 to 0.1 s) and motor potential (MP; 0.1 to +0.1 s). Results: During BP, the strongest PCA component represented a radially oriented dipole located approximately at the vertex. It was increasing in strength. The second component suggested a tangential bilateral dipole in the fronto-parietal direction with a variable time course. During NS, the strongest component was radial and centrally oriented as well. The tangential component during NS was similar to BP but more pronounced. Both components were increasing in strength during the interval. During MP, the only unequivocal component was tangential, located bilaterally over the motor cortex, with a rising time course.