- Email: [email protected]
PS-11-6 Brain evoked response to transcranial magnetic stimulation
Postersession 11. Transcranialmagnetic stimulation (2) mained quite marked up to 11 ms. This was the most constant effect observed in both hemispheres of each subject. We concluded that for clinical purposes, inhibition should be tested at 11 ms and exitation at 4 ms.
[ PS-11-4 t The dopamine receptor agonist pergolide enhances corUco-cortical inhibition in normal subjects: a transcranial magnetic stimulation study Ulf Ziemann, Dirk Bruns, Walter Paulus. Department of Clinical Neurophysiology, University of G6ttingen, Germany Pergolide mesylate is a direct-acting dopamine agonist which is now used as an effective adjunctive drug in the levodopa treatment of Parkinson's disease (PD). In the present study the effect of a single oral dose of 0.25 mg pergolide on the excitability of the motor cortex was investigated by means of focal transcranial magnetic stimulation (TMS) in six healthy volunteers (mean age 36 years). Motor thresholds in the resting and active abductor digiti minimi muscle, the duration of the cortical silent period (CSP), and the cortico-cortical inhibition and facilitation after paired cortical stimulation (range of interstimulus intervals 1-30 msec) were investigated as various aspects of motor system excitability. Measurements were done baseline and 1, 3, 6 and 24 hours after pergolide intake. Motor thresholds and CSP duration remained unchanged throughout. The cortico-cortical inhibition was significantly enhanced (2 p < 0.05; t test for paired samples) at interstimulus intervals of 2, 4 to 7 msec with a maximum effect at 3 and 6 hours and a return to baseline at 24 hours. The cortico-cortical facilitation at longer intervals was not affected. TMS is a non-invasive technique which allows the investigation of the modulation of h u m a n cortex excitability by antiparkinsonian drugs in vivo. The e n h a n c e m e n t of cortico-cortical inhibition by pergolide is exactly the reverse of the reduction of inhibition seen in PD during the OFF-phase. This indicates that pergolide is likely to restore deficient motor cortical inhibition in PD.
Cortico-cortical IPS-1 1~5 J cortical lesion
inhibition in focal motor
Takashi Kujirai 1, Katsurou Kurokawa l, Kayoko Kujirai 2, Hideo Sasaki 1. i The Third Department oflnternal Medicine,
Yamagata University School of Medicine, Yamagata, Japan; 2 National Sanatorium Yamagata Hospital, Yamagata, Japan Disturbed discrete movement in hands may be associated with motor cortical lesion. Patients with focal motor cortical lesion, however, are few and it is very difficult to identify that the disturbance is derived from the motor cortex: Recently double magnetic stimulation method (Kujirai et al, 1993) has been developed and contributed to the application of clinical usage. When the intensity of the conditioning stimulation (C)is lower than the motor threshold, the first conditioning shock greatly inhibits the following test response (T), showing suppression up to 6 ms of the interstimulus intervals. The inhibition is considered to occur at the motor cortex. Along the local ethnic committee approval, we studied a 67-year-old man who suddenly developed the disturbed discrete movement in his right hand and recovered in a couple of months. Only minor abnormality such as Garcin's and digiti quiniti signs was detected. Conventional neurological examinations revealed no abnormality. M R I brain scan disclosed focal small lesion just around the left hand motor area, suggesting a minor stroke. Using Paired magnetic stimulation method, we studied cotrico-cortical
S109
inhibition on his both hands. There was no inhibition on his right hand whereas almost normal on his left. PSTH (post stimulus time histogram) method on his first dorsal interossei muscle showed poor organization of recurrent peaks. In conclusion, double stimulation technique is useful for detecting focal cortical lesion, even a minor lesion.
PS-1 1-6 I Brain evoked response to transcranial
magnetic stimulation Shin-lchi lzumi z, Moriichiro Takase 2, Naoichi Chino 3, Motohide Arita 3, Yoshihisa Masakado 3, Akio Kimura 3.
l Department of Rehabilitation Medicine, Tokai University, School of Medicine; 2 Clinical EEG Laboratory, Keio University, School of Medicine; 3Department of Rehabilitation Medicine, Keio University, School of Medicine Electroencephalographic ( E E G ) changes and evoked responses induced by transcranial magnetic stimulation (TMS) were demonstrated using an artifact-interrupting circuit designed to provide 150-msec input interruption after a trigger. Five healthy males (aged 23-37 years) served as subjects. The center of a round coil was positioned at Cz, and TMS was delivered at maximal output in a clockwise current, every 3-5 seconds, a total of 80 times. E E G s were recorded through leads F3, F4, C3, Ca, P3, P4, T4 and T4. EEGs for 2 seconds after all stimulations were averaged. Immediately after stimulation, complex waves appeared in which slow waves, or occasionally, fast waves were superimposed on a gentle positive component. The mean duration of E E G changes was 400--600 msec in the frontal, central and parietal areas on each side with no significant differences between the groups, but was significantly shorter (about 220 msec) in the temporal area (p < 0.05). There were no statistically significant differences between the right and left sides. Brain evoked potentials consists of a slow positive component that fused with 0-3 negative peaks. The primary positive peak latency was about 200 msec, and the negative peak latency was within 600 msec. It is concluded that TMS induces short-term E E G changes and brain evoked potentials.
[ PS-11-7 1 Delay of visual reaction time by transcranial magnetic stimulation to the occipital codex Hiroshi Abe, Jiro Tatsuno. Department of Physiology, National Defense Medical College, Japan To investigate the effect of magnetic stimulation to the reaction time we gave magnetic stimulation transcranially to the occipital cortex during the test of visual reaction time. Subjects were 6 normal volunteers aged 21-35. The subject was seated and pushed button with his right thumb when random visual stimulations (illuminations of red light-emitting diode, 1 meter before him) were given. Magnetic stimulations were given after the visual stimulations with some interval time (0 msec-300 msee). We used Nihon Kohden's magnetic stimulator SMN1100 and round magnetic coil, 13.7 cm in diameter. The coil was placed across the occipital midline with its center on Oz of Intern.ational ten-twenty method. Stimulation intensity was 80-90% of the maximum output of the stimulator (1.3 Tesla). The direction of the electric current in the coil was clockwise. Reaction time was measured 40 times without magnetic stimulation for control and 20-40 times with magnetic stimulation in each interval time. W h e n the interval time was 0 to 40 msec, magnetic stimulations did not cause delay of the reaction time in all 6 subjects. And when the interval time was 60-150 msec, delays of 30-60 msec from the control were observed. These results suggest that the magnetic stimulations with 60-150 msec
[ PS-11-4 t The dopamine receptor agonist pergolide enhances corUco-cortical inhibition in normal subjects: a transcranial magnetic stimulation study Ulf Ziemann, Dirk Bruns, Walter Paulus. Department of Clinical Neurophysiology, University of G6ttingen, Germany Pergolide mesylate is a direct-acting dopamine agonist which is now used as an effective adjunctive drug in the levodopa treatment of Parkinson's disease (PD). In the present study the effect of a single oral dose of 0.25 mg pergolide on the excitability of the motor cortex was investigated by means of focal transcranial magnetic stimulation (TMS) in six healthy volunteers (mean age 36 years). Motor thresholds in the resting and active abductor digiti minimi muscle, the duration of the cortical silent period (CSP), and the cortico-cortical inhibition and facilitation after paired cortical stimulation (range of interstimulus intervals 1-30 msec) were investigated as various aspects of motor system excitability. Measurements were done baseline and 1, 3, 6 and 24 hours after pergolide intake. Motor thresholds and CSP duration remained unchanged throughout. The cortico-cortical inhibition was significantly enhanced (2 p < 0.05; t test for paired samples) at interstimulus intervals of 2, 4 to 7 msec with a maximum effect at 3 and 6 hours and a return to baseline at 24 hours. The cortico-cortical facilitation at longer intervals was not affected. TMS is a non-invasive technique which allows the investigation of the modulation of h u m a n cortex excitability by antiparkinsonian drugs in vivo. The e n h a n c e m e n t of cortico-cortical inhibition by pergolide is exactly the reverse of the reduction of inhibition seen in PD during the OFF-phase. This indicates that pergolide is likely to restore deficient motor cortical inhibition in PD.
Cortico-cortical IPS-1 1~5 J cortical lesion
inhibition in focal motor
Takashi Kujirai 1, Katsurou Kurokawa l, Kayoko Kujirai 2, Hideo Sasaki 1. i The Third Department oflnternal Medicine,
Yamagata University School of Medicine, Yamagata, Japan; 2 National Sanatorium Yamagata Hospital, Yamagata, Japan Disturbed discrete movement in hands may be associated with motor cortical lesion. Patients with focal motor cortical lesion, however, are few and it is very difficult to identify that the disturbance is derived from the motor cortex: Recently double magnetic stimulation method (Kujirai et al, 1993) has been developed and contributed to the application of clinical usage. When the intensity of the conditioning stimulation (C)is lower than the motor threshold, the first conditioning shock greatly inhibits the following test response (T), showing suppression up to 6 ms of the interstimulus intervals. The inhibition is considered to occur at the motor cortex. Along the local ethnic committee approval, we studied a 67-year-old man who suddenly developed the disturbed discrete movement in his right hand and recovered in a couple of months. Only minor abnormality such as Garcin's and digiti quiniti signs was detected. Conventional neurological examinations revealed no abnormality. M R I brain scan disclosed focal small lesion just around the left hand motor area, suggesting a minor stroke. Using Paired magnetic stimulation method, we studied cotrico-cortical
S109
inhibition on his both hands. There was no inhibition on his right hand whereas almost normal on his left. PSTH (post stimulus time histogram) method on his first dorsal interossei muscle showed poor organization of recurrent peaks. In conclusion, double stimulation technique is useful for detecting focal cortical lesion, even a minor lesion.
PS-1 1-6 I Brain evoked response to transcranial
magnetic stimulation Shin-lchi lzumi z, Moriichiro Takase 2, Naoichi Chino 3, Motohide Arita 3, Yoshihisa Masakado 3, Akio Kimura 3.
l Department of Rehabilitation Medicine, Tokai University, School of Medicine; 2 Clinical EEG Laboratory, Keio University, School of Medicine; 3Department of Rehabilitation Medicine, Keio University, School of Medicine Electroencephalographic ( E E G ) changes and evoked responses induced by transcranial magnetic stimulation (TMS) were demonstrated using an artifact-interrupting circuit designed to provide 150-msec input interruption after a trigger. Five healthy males (aged 23-37 years) served as subjects. The center of a round coil was positioned at Cz, and TMS was delivered at maximal output in a clockwise current, every 3-5 seconds, a total of 80 times. E E G s were recorded through leads F3, F4, C3, Ca, P3, P4, T4 and T4. EEGs for 2 seconds after all stimulations were averaged. Immediately after stimulation, complex waves appeared in which slow waves, or occasionally, fast waves were superimposed on a gentle positive component. The mean duration of E E G changes was 400--600 msec in the frontal, central and parietal areas on each side with no significant differences between the groups, but was significantly shorter (about 220 msec) in the temporal area (p < 0.05). There were no statistically significant differences between the right and left sides. Brain evoked potentials consists of a slow positive component that fused with 0-3 negative peaks. The primary positive peak latency was about 200 msec, and the negative peak latency was within 600 msec. It is concluded that TMS induces short-term E E G changes and brain evoked potentials.
[ PS-11-7 1 Delay of visual reaction time by transcranial magnetic stimulation to the occipital codex Hiroshi Abe, Jiro Tatsuno. Department of Physiology, National Defense Medical College, Japan To investigate the effect of magnetic stimulation to the reaction time we gave magnetic stimulation transcranially to the occipital cortex during the test of visual reaction time. Subjects were 6 normal volunteers aged 21-35. The subject was seated and pushed button with his right thumb when random visual stimulations (illuminations of red light-emitting diode, 1 meter before him) were given. Magnetic stimulations were given after the visual stimulations with some interval time (0 msec-300 msee). We used Nihon Kohden's magnetic stimulator SMN1100 and round magnetic coil, 13.7 cm in diameter. The coil was placed across the occipital midline with its center on Oz of Intern.ational ten-twenty method. Stimulation intensity was 80-90% of the maximum output of the stimulator (1.3 Tesla). The direction of the electric current in the coil was clockwise. Reaction time was measured 40 times without magnetic stimulation for control and 20-40 times with magnetic stimulation in each interval time. W h e n the interval time was 0 to 40 msec, magnetic stimulations did not cause delay of the reaction time in all 6 subjects. And when the interval time was 60-150 msec, delays of 30-60 msec from the control were observed. These results suggest that the magnetic stimulations with 60-150 msec