Sadatoshi Tsuji

Effect of transcranial DC sensorimotor cortex stimulation on somatosensory evoked potentials in humans

OBJECTIVEnTo study the after-effect of transcranial direct current stimulation (tDCS) over the sensorimotor cortex on the size of somatosensory evoked potentials (SEPs) in humans.nnnMETHODSnSEPs were elicited by electrical stimulation of right or left median nerve at the wrist before and after anodal or cathodal tDCS in 8 healthy subjects. tDCS was applied for 10 min to the left motor cortex at a current strength of 1 mA.nnnRESULTSnAmplitudes of P25/N33, N33/P40 (parietal components) and P22/N30 (frontal component) following right median nerve stimulation were significantly increased for at least 60 min after the end of anodal tDCS, whereas P14/N20, N20/P25 (parietal components) and N18/P22 (frontal component) were unaffected. There was no effect on SEPs evoked by left median nerve stimulation. Cathodal tDCS had no effect on SEPs evoked from stimulation of either arm.nnnCONCLUSIONSnAnodal tDCS over the sensorimotor cortex can induce a long-lasting increase in the size of ipsilateral cortical components of SEPs.nnnSIGNIFICANCEntDCS can modulate cortical somatosensory processing in humans and might be a useful tool to induce plasticity in cortical sensory processing.

Increased corticospinal excitability after 5 Hz rTMS over the human supplementary motor area.

Transcranial magnetic stimulation (TMS) can produce effects not only at the site of stimulation but also at distant sites to which it projects. Here we examined the connection between supplementary motor area (SMA) and the hand area of the primary motor cortex (M1Hand) by testing whether prolonged repetitive TMS (rTMS) over the SMA can produce changes in excitability of the M1Hand after the end of the stimulus train. We evaluated motor‐evoked potentials (MEPs) and the cortical silent period (CSP) evoked by a single‐pulse TMS, short‐interval intracortical inhibition (SICI) and intracortical facilitation (ICF) produced by a paired‐pulse TMS, and forearm flexor H reflexes before and after 750 pulses of 5 Hz rTMS over SMA at an intensity of 110% active motor threshold (AMT) for the first dorsal interosseous (FDI) muscle. The amplitude of MEPs recorded from the right FDI muscle at rest as well as during voluntary contraction increased for at least 10 min after the end of rTMS, although the duration of the CSP, SICI and ICF did not change. There was no effect on H reflexes in the flexor carpi radialis muscle, even though the amplitude of the MEP obtained from the same muscle increased after rTMS. The effects on MEPs depended on the intensity of rTMS and were spatially specific to the SMA proper. We suggest that 5 Hz rTMS over SMA can induce a short‐lasting facilitation in excitability of the M1Hand compatible with the anatomical connections between SMA and the M1Hand.

Cyclooxygenase-2 expression in the hippocampus of genetically epilepsy susceptible El mice was increased after seizure

It has been suggested that cyclooxygenase (COX)-2 and prostaglandin play a role in epilepsy. We studied the expression of COX-2 in the hippocampus and the effect of oral administration of indomethacin, a COX inhibitor, on seizure activity in genetically seizure-susceptible El mice. COX-2 protein significantly increased in the hippocampi of El mice after epileptic seizure. Indomethacin did shorten the duration from seizure onset to full recovery in El mice although the threshold and the duration of seizure were not changed.

Usefulness of Quantitative Susceptibility Mapping for the Diagnosis of Parkinson Disease

BACKGROUND AND PURPOSE: Quantitative susceptibility mapping allows overcoming several nonlocal restrictions of susceptibility-weighted and phase imaging and enables quantification of magnetic susceptibility. We compared the diagnostic accuracy of quantitative susceptibility mapping and R2* (1/T2*) mapping to discriminate between patients with Parkinson disease and controls. MATERIALS AND METHODS: For 21 patients with Parkinson disease and 21 age- and sex-matched controls, 2 radiologists measured the quantitative susceptibility mapping values and R2* values in 6 brain structures (the thalamus, putamen, caudate nucleus, pallidum, substantia nigra, and red nucleus). RESULTS: The quantitative susceptibility mapping values and R2* values of the substantia nigra were significantly higher in patients with Parkinson disease (P < .01); measurements in other brain regions did not differ significantly between patients and controls. For the discrimination of patients with Parkinson disease from controls, receiver operating characteristic analysis suggested that the optimal cutoff values for the substantia nigra, based on the Youden Index, were >0.210 for quantitative susceptibility mapping and >28.8 for R2*. The sensitivity, specificity, and accuracy of quantitative susceptibility mapping were 90% (19 of 21), 86% (18 of 21), and 88% (37 of 42), respectively; for R2* mapping, they were 81% (17 of 21), 52% (11 of 21), and 67% (28 of 42). Pair-wise comparisons showed that the areas under the receiver operating characteristic curves were significantly larger for quantitative susceptibility mapping than for R2* mapping (0.91 versus 0.69, P < .05). CONCLUSIONS: Quantitative susceptibility mapping showed higher diagnostic performance than R2* mapping for the discrimination between patients with Parkinson disease and controls.

Effects of interferon-β on the cytokine production of astrocytes

Abstract The effects of interferon (IFN)-β used for treatment of multiple sclerosis (MS) on the central nervous system (CNS) have not yet been elucidated. The effect of IFN-β and IFN-γ on astrocytes as the major component of the CNS was investigated using murine primary astrocytes and human astrocytoma U251 cell line. IL-1β, IL-6, TNF-α and iNOS were analyzed by RT-PCR. Both protein and mRNA levels of IL-6 were increased by IFN-β. IFN-γ augmented the effect of IFN-β on IL-6 production. These results suggest that IFN-β has an activity to modulate inflammatory and immune responses by up-regulating IL-6 in the CNS of MS.

Motor hand representation in cortical area 44

Objective: To elucidate whether area 44 of human frontal cortex is essential for the organization of voluntary hand movements or not, the authors examined effects of single transcranial magnetic stimulation (TMS) of human area 44 on voluntary hand movement and electromyography (EMG) activities in hand muscles. Method: Surface EMG responses were recorded from the thenar muscles of 10 normal subjects following TMS over area 44. Stimuli were applied 2 cm anterior to the primary tongue motor area. Results: Single TMS over area 44 could easily interrupt target-oriented hand movements. Human area 44 has facilitatory and inhibitory effects over both tonic and phasic finger movements. It is shown that single TMS of area 44 produces motor evoked potential from hand muscles. Conclusion: Human area 44 is involved in voluntary hand movements and has direct fast-conducting corticospinal projections.

Ameliorative effect of pioglitazone on seizure responses in genetically epilepsy-susceptible EL mice

Pioglitazone, a peroxisome proliferator-activated receptor-gamma agonist, delayed the development of seizure responses and mildly shortened the duration of convulsion of genetically epileptic EL mice. mRNA levels of IL-1beta, IL-6 and TNF-alpha before seizure and mRNA levels of IL-6 and TNF-alpha after seizure were decreased in the brains of the mice with pioglitazone. These results suggest that pioglitazone may have ameliorative effects on epileptic seizure responses partly through the reduction of inflammatory responses in the brain.

Green odor attenuates a cold pressor test-induced cardiovascular response in healthy adults

BackgroundGreen odor, a mixture of equal amounts of 2E-hexenal (leaf aldehyde) and 3Z-hexenol (leaf alcohol) has been demonstrated to have an anti-stress effect in rats. This study investigated whether or not green odor also has an anti-stress effect in humans.MethodsChanges in blood pressure, heart rate, and the skin temperature of a fingertip were observed after presenting green odor at a concentration of 0.03% or vehicle via inhalation through the nose for 10 min to eight healthy normotensive adults. We also assessed the pleasantness of green odor and its effect on mood states via assessment with the Profile of Mood States (POMS) questionnaire. Cardiovascular response to green odor and the vehicle were compared among 11 additional healthy adults by use of the cold pressor test.ResultsOf 19 subjects, 15 (79%) reported that the green odor was pleasant. Green odor had no effect on blood pressure, heart rate, skin temperature, or POMS score under non-stressful conditions. In the second experiment, green odor attenuated cold pressor test-induced increases in systolic and diastolic blood pressure and facilitated the recovery of skin temperature.ConclusionThese findings suggest that green odor has an anti-stress effect in healthy humans.

Internal structures of the globus pallidus in patients with Parkinson’s disease: evaluation with quantitative susceptibility mapping (QSM)

AbstractObjectivesThe aim of this study was to assess the susceptibility change in medial and lateral globus pallidus (GPm and GPl) related to age separately, using quantitative susceptibility mapping (QSM) and to determine whether QSM can depict GPm in Parkinson’s disease (PD) patients.MethodsQSM was performed in 19 PD patients and in 41 normal control (NC) subjects. First, we quantitatively analysed age-related changes in QSM value in NC for GPl and GPm by a manual region of interest (ROI) technique. Then, in PD patients and age-matched NC subjects, we evaluated the depiction of GPm on QSM images qualitatively.ResultsIn NC, the QSM value within GPl significantly increased gradually with age (ru2009=u20090.32, pu2009=u20090.04), whereas it did not change with age in GPm. The average QSM value was significantly larger for GPl than for GPm (205 vs 191, pu2009<u20090.05). In both PD patients and age-matched NC, the depiction of GPm on QSM images was good in most cases (87xa0%, 33 of 38 sides in PD patients) mainly because of the differences in susceptibility between GPm and GPl.ConclusionsThe QSM value in GPl increases gradually with age, which allows for the identification of GPm in elderly PD subjects.Key points• QSM can delineate the differences in susceptibility between GPm and GPl.n • QSM value within GPl increased with age, but not within GPm.n • MR imaging with QSM can depict GPm in PD patients.

A novel tract imaging technique of the brainstem using phase difference enhanced imaging: normal anatomy and initial experience in multiple system atrophy

ObjectivesTo develop a new tract imaging technique for visualising small fibre tracts of the brainstem and for detecting the abnormalities in multiple system atrophy of the cerebellar type (MSA-C) using a phase difference enhanced (PADRE) imaging technique, in which the phase difference between the target and surrounding tissue is selectively enhanced.MethodsTwo neuroradiologists compared the high-spatial-resolution PADRE imaging, which was acquired from six healthy volunteers, three patients with MSA-C, and 7 patients with other types of neurodegenerative diseases involving the brainstem or cerebellum.ResultsVarious fine fibre tracts in the brainstem, the superior and inferior cerebellar peduncles, medial lemniscus, spinothalamic tract, medial longitudinal fasciculus, central tegmental tract, corticospinal tract and transverse pontine fibres, were identified on PADRE imaging. PADRE imaging from MSA-C demonstrated the disappearance of transverse pontine fibres and significant atrophy of the inferior cerebellar peduncles, while the superior cerebellar peduncles were intact. PADRE imaging also demonstrated that the transverse pontine fibres and inferior cerebellar peduncle were not involved in the other neurodegenerative diseases.ConclusionPADRE imaging can offer a new form of tract imaging of the brainstem and may have the potential to reinforce the clinical utility of MRI in differentiating MSA from other conditions.