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1.
Clin Neurol Neurosurg ; 172: 162-168, 2018 09.
Article in English | MEDLINE | ID: mdl-30016754

ABSTRACT

OBJECTIVES: The establishment of biomarkers for amyotrophic lateral sclerosis (ALS) will be useful for early diagnosis and may provide evidence about pathogenesis. To elucidate whether high-field magnetic resonance (MR) findings and multimodal analysis of cerebrospinal fluid (CSF) levels of cystatin C could be indicators of upper motor neuron (UMN) involvement in ALS. PATIENTS AND METHODS: Patients with ALS (n = 20), multiple sclerosis (n = 15), immune mediated chronic polyneuropathy (n = 17), and acute polyneuropathy (n = 12) were included in this retrospective study. Clinical indices including UMN signs were assessed, and 3.0-Tesla diffusion tensor imaging and MR spectroscopy were performed in patients with ALS. CSF levels of cystatin C were measured using enzyme-linked immunosorbent assay. RESULTS: MR findings indicated that decreased anisotropy, increased diffusion, and increased myo-inositol/creatine ratio were also significantly correlated with UMN involvement in patients with ALS. The CSF cystatin C levels were significantly lower in patients with ALS than in the other three groups. The reduction of CSF cystatin C levels was significantly correlated with clinical UMN involvement (r = -0.505, p =  0.023). CONCLUSIONS: Reduced cystatin C in CSF can reflect UMN involvement as shown in high-field MR of ALS, potentially providing a new biomarker for UMN degeneration in ALS.


Subject(s)
Amyotrophic Lateral Sclerosis/cerebrospinal fluid , Biomarkers/cerebrospinal fluid , Cystatin C/cerebrospinal fluid , Motor Neurons/pathology , Adult , Aged , Aged, 80 and over , Amyotrophic Lateral Sclerosis/pathology , Diffusion Magnetic Resonance Imaging/methods , Diffusion Tensor Imaging/methods , Female , Humans , Magnetic Resonance Spectroscopy/methods , Male , Middle Aged , Multimodal Imaging/methods , Nerve Degeneration/pathology
2.
J Med Invest ; 61(1-2): 79-83, 2014.
Article in English | MEDLINE | ID: mdl-24705753

ABSTRACT

It has been reported that negative emotional changes and conditions affect the visual faculties of humans at the neural level. On the other hand, the effects of emotion on color perception in particular, which are based on evoked potentials, are unknown. In the present study, we investigated whether different anxiety levels affect the color information processing for each of 3 wavelengths by using flash visual evoked potentials (FVEPs) and State-Trait Anxiety Inventory. In results, significant positive correlations were observed between FVEP amplitudes and state or trait anxiety scores in the long (sensed as red) and middle (sensed as green) wavelengths. On the other hand, short-wavelength-evoked FVEPs were not correlated with anxiety level. Our results suggest that negative emotional conditions may affect color sense processing in humans.


Subject(s)
Anxiety/physiopathology , Color Perception/physiology , Color , Evoked Potentials, Visual/physiology , Adult , Anxiety/psychology , Emotions/physiology , Humans , Intelligence Tests , Male , Severity of Illness Index
4.
J Med Invest ; 57(1-2): 109-13, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20299749

ABSTRACT

In order to investigate the transcallosal effects of repetitive transcranial magnetic stimulation (rTMS), we studied median somatosensory evoked potentials (SEPs) before and after applying monophasic very low-frequency (0.2 Hz) subthreshold rTMS over the right motor cortex. For SEPs, median nerve was stimulated on each side. Sham rTMS served as the control. Twelve healthy subjects participated in this study. After rTMS over the right hemisphere, the amplitude of N34 component in right median SEPs recorded from the left parietal scalp (C3') increased significantly. Other components of right or left median SEPs or those after sham stimulation showed no changes. Monophasic 0.2 Hz subthreshold rTMS over the motor cortex predominantly affected the contralateral SEPs, probably through the transcallosal pathway.


Subject(s)
Evoked Potentials, Somatosensory/physiology , Motor Cortex/physiology , Transcranial Magnetic Stimulation , Adult , Humans , Male
5.
Clin Neurophysiol ; 119(11): 2538-45, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18835216

ABSTRACT

OBJECTIVE: To optimize the clinical uses of repetitive transcranial magnetic stimulation (rTMS), we compared the effects of rTMS on somatosensory-evoked potentials (SEPs) and regional cerebral blood flow (rCBF) using different phases (monophasic vs. biphasic) or frequencies (0.2Hz vs. 0.8Hz) of stimulation. METHODS: In the first experiment, different phases were compared (0.2Hz monophasic vs. 0.2Hz biphasic). Biphasic 1Hz or sham condition served as controls. The second experiment was to explore the effect of frequencies (0.2Hz vs. 0.8Hz) using the monophasic stimulation. Substhreshold TMS was applied 250 times over the left premotor cortex. Single photon emission computed tomography (SPECT) was performed before and after monophasic 0.2Hz or biphasic 1Hz rTMS. RESULTS: Monophasic rTMS of both 0.2 and 0.8Hz significantly increased the ratio of N30 amplitudes as compared with sham rTMS, whereas biphasic stimulation showed no significant effects. SPECT showed increased rCBF in motor cortices after monophasic 0.2Hz rTMS, but not after biphasic 1Hz stimulation. CONCLUSIONS: Monophasic rTMS exerted more profound effects on SEPs and rCBF than biphasic rTMS over the premotor cortex. SIGNIFICANCE: Monophasic rTMS over the premotor cortex could be clinically more useful than biphasic rTMS.


Subject(s)
Brain Mapping , Evoked Potentials, Somatosensory/physiology , Somatosensory Cortex , Tomography, Emission-Computed, Single-Photon , Transcranial Magnetic Stimulation , Adult , Analysis of Variance , Cerebrovascular Circulation/physiology , Cerebrovascular Circulation/radiation effects , Dose-Response Relationship, Radiation , Electric Stimulation , Female , Humans , Male , Somatosensory Cortex/blood supply , Somatosensory Cortex/diagnostic imaging , Somatosensory Cortex/physiology , Time Factors , Young Adult
7.
Neuroimage ; 31(2): 699-709, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16466934

ABSTRACT

Somatosensory-evoked potentials (SEPs) are attenuated by movement. This phenomenon of 'gating' reflects sensorimotor integration for motor control. The frontal N30 component after median nerve stimulation was shown to be reduced in amplitude prior to hand movement. To investigate the mechanism of this sensory gating, we recorded median SEPs immediately before and after application of monophasic very low-frequency (0.2 Hz) repetitive transcranial magnetic stimulation (rTMS) of 250 stimuli over motor cortex (MC), premotor cortex (PMC), or supplementary motor area (SMA) in 9 healthy volunteers. The stimulus intensity for MC or PMC was set 85% of the resting motor threshold for the hand muscle, and that for SMA was at the active motor threshold for the leg muscle. SEPs showed significant increases in amplitudes of the frontal N30 component after PMC stimulation, but not after SMA or MC stimulation. Low-frequency (1 Hz) biphasic stimulation over PMC showed no significant N30 changes in 6 out of 9 subjects tested, indicating the effect being specific for 0.2 Hz monophasic stimulation. To examine the functional anatomy of the N30 change, single photon emission computed tomography was performed immediately before and after monophasic 0.2 Hz rTMS over PMC in all the 9 subjects. Regional cerebral blood flow showed significant increases mainly in PMC and prefrontal cortex, indicating the involvement of these cortical areas in sensory input gating for motor control.


Subject(s)
Brain Mapping , Brain/physiology , Cerebrovascular Circulation/physiology , Evoked Potentials, Somatosensory/physiology , Motor Cortex/physiology , Regional Blood Flow/physiology , Transcranial Magnetic Stimulation , Adult , Brain/anatomy & histology , Functional Laterality , Humans , Male
9.
Brain ; 128(Pt 1): 104-15, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15483042

ABSTRACT

Writer's cramp, or focal hand dystonia, is characterized by involuntary coactivation of antagonist or unnecessary muscles while writing or performing other tasks. Although the mechanism underlying this muscle overactivation is unknown, recent studies of changes in cerebral blood flow during writing have demonstrated a reduction in the activation of the primary motor cortex (MC) and hyperactivity of parts of the frontal non-primary motor areas. Therefore, any measures that decrease the activities of non-primary motor areas such as the premotor cortex (PMC) and the supplementary motor area (SMA) might improve dystonic symptoms. To explore this possibility, we studied nine patients with writer's cramp and seven age-matched control subjects, using subthreshold low-frequency (0.2 Hz) repetitive transcranial magnetic stimulation (rTMS), which exerts an inhibitory action on the cortex. Previous studies have demonstrated shortened cortical silent periods in dystonia, suggesting deficient cortical inhibition in the MC. We compared the silent periods and computer-assisted ratings of handwriting before and after rTMS applied to the MC, SMA or PMC. We also used the sham coil for control runs. Stimulation of the PMC but not the MC significantly improved the rating of handwriting (mean tracking error from the target, P = 0.004; pen pressure, P = 0.01) and prolonged the silent period (P = 0.02) in the patient group. rTMS over the other sites or using a sham coil in the patient group or trials in the control group revealed no physiological or clinical changes. This increased susceptibility of the PMC in dystonia suggests that the lack of inhibition in the MC is secondary to the hyperactivity of PMC neurons. Inhibition of the PMC using rTMS could provide a therapeutic measure of writer's cramp.


Subject(s)
Dystonic Disorders/physiopathology , Motor Cortex/physiopathology , Transcranial Magnetic Stimulation , Adult , Electromyography , Evoked Potentials, Motor/physiology , Female , Hand/physiopathology , Handwriting , Humans , Male , Neural Inhibition/physiology , Physical Stimulation/methods , Signal Processing, Computer-Assisted/instrumentation
11.
Neuroreport ; 14(3): 375-9, 2003 Mar 03.
Article in English | MEDLINE | ID: mdl-12634487

ABSTRACT

Somatosensory evoked potentials (SEPs) are attenuated or gated during movement. The mechanism for this includes both centrifugal gating of afferent input and competition with other afferents caused by the movement (peripheral gating). Using a paradigm in which the signal for triggering movement is the electric stimulus for SEPs, we studied the gating of SEPs after tibial nerve stimulation prior to foot movement, and compared it with that during counting task. Significant gating was found for P40 component, which distributed centrally and ipsilaterally to the side of the stimulation, whereas the contralateral N40 component showed no changes. Dissociated gating of P40 and N40 indicates multiple generators of these components, in contrast to the previous view of a single generator dipole projecting tangentially. Together with the previous findings in median SEPs, these gating phenomena should represent a general mechanism for sensori-motor integration in preparation for limb movement.


Subject(s)
Evoked Potentials, Somatosensory/physiology , Movement/physiology , Tibial Nerve/physiology , Adult , Brain Mapping , Cues , Electric Stimulation , Foot , Humans , Male , Mathematics , Mental Processes/physiology , Middle Aged , Sound
12.
Sleep ; 25(8): 877-81, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12489894

ABSTRACT

STUDY OBJECTIVES: The aim of this study was to investigate the issue of whether REM sleep is involved in implicit learning through the cerebellum-related neural circuit via the use of classical eyeblink conditioning (CEC). DESIGN: Subjects were divided into three groups: control (sleep without interruption), REM sleep deprivation (RD), and slow wave sleep (stage 3+4) deprivation (SD). The CEC was performed after 8 hours of ordinary nocturnal sleep or sleep disrupted at a selected sleep stage. SETTING: A university-based sleep laboratory. PATIENTS OR PARTICIPANTS: Twenty-seven healthy volunteers (all men, aged 23.2+/-0.6 years). INTERVENTIONS: The CEC was measured after selective sleep deprivation or ordinary nocturnal sleep. MEASUREMENTS AND RESULTS: The eyeblink reflex was conditioned using a classical delay conditioning paradigm. The conditioned response (CR) was determined by electromyography measurements of the orbicularis oculi muscles. The rate of appearance of the CR was compared among the three groups. Compared with the control subjects, RD subjects were significantly deficient in their capacity to acquire conditioned eyeblinks, while no difference was found among the SD subjects. CONCLUSIONS: This study suggests that RD suppresses the cerebellar function in CEC and that REM sleep is closely linked with the learning function in the cerebellum.


Subject(s)
Blinking/physiology , Conditioning, Classical/physiology , Sleep Deprivation/physiopathology , Sleep, REM/physiology , Adult , Cerebellum/physiopathology , Electromyography , Electrooculography , Eyelids/physiology , Facial Muscles/physiology , Humans , Learning/physiology , Male , Neural Inhibition/physiology , Polysomnography , Purkinje Cells/physiology , Sleep/physiology , Sleep Deprivation/diagnosis
13.
Brain Res ; 928(1-2): 194-201, 2002 Feb 22.
Article in English | MEDLINE | ID: mdl-11844487

ABSTRACT

Parkinson's disease (PD) patients with autonomic failure show no nocturnal decrease in blood pressure (BP). At present, it is not clear if this symptom is attributable to the disturbance of the dopaminergic (DA) system that is responsible for PD. In the present study, we determined that the mesolimbic DA system is involved in diurnal profiles of the mean BP (MBP) by destroying the A10 DA system in rats with 6-hydroxydopamine. In control rats, a clear dip in the MBP and heart rate (HR) occurs during the light, that is, resting period, analogous to the nocturnal dip in normal humans. This normal daytime decrease in MBP and HR was disturbed by inducing a lesion of the ventral tegmental area (VTA) DA neurons, although the rhythms of wake-sleep duration and behavioral activity remained relatively intact. On the basis of this evidence, the absence of a nocturnal dip in BP in PD patients is attributed to impairment of the mesolimbic DA system.


Subject(s)
Cardiovascular Physiological Phenomena/drug effects , Chronobiology Disorders/physiopathology , Circadian Rhythm/physiology , Neural Pathways/physiopathology , Neurons/metabolism , Nucleus Accumbens/physiopathology , Ventral Tegmental Area/physiopathology , Animals , Blood Pressure/drug effects , Blood Pressure/physiology , Chronobiology Disorders/etiology , Chronobiology Disorders/pathology , Circadian Rhythm/drug effects , Dopamine/metabolism , Heart Rate/drug effects , Heart Rate/physiology , Immunohistochemistry , Male , Neural Pathways/drug effects , Neural Pathways/pathology , Neurons/drug effects , Neurons/pathology , Nucleus Accumbens/drug effects , Nucleus Accumbens/pathology , Oxidopamine/pharmacology , Parkinson Disease/pathology , Parkinson Disease/physiopathology , Rats , Rats, Wistar , Sleep/drug effects , Sleep/physiology , Sleep, REM/drug effects , Sleep, REM/physiology , Sympatholytics/pharmacology , Tyrosine 3-Monooxygenase/metabolism , Ventral Tegmental Area/drug effects , Ventral Tegmental Area/pathology , Wakefulness/drug effects , Wakefulness/physiology
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