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1.
J Clin Med ; 13(5)2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38592314

RESUMO

Background: We conducted a systematic review and meta-analysis to examine the feasibility of paclitaxel-coated balloon (PCB) angioplasty for de novo lesions in patients with acute coronary syndrome (ACS) by comparing with drug-eluting stent (DES) placement. Methods: By a systematic literature search, nine (five randomized controlled, two retrospective propensity-score matched, and two retrospective baseline-balanced) studies comparing the midterm clinical and angiographic outcomes after PCB angioplasty and DES placement were included, yielding 974 and 1130 ACS cases in PCB and DES groups, respectively. Major adverse cardiac event (MACE) was defined as a composite of cardiac mortality (CM), all-cause mortality (ACM), myocardial infarction (MI), target vessel revascularization (TVR), and target lesion revascularization (TLR). Late luminal loss (LLL) and bleeding events (BLD) were also estimated. Results: The frequencies of MACE in PCB and DES groups were 8.42% and 10.62%, respectively. PCB angioplasty had no significant impacts on all of MACE (risk ratio: 0.90, 95%CI: 0.68-1.18, p = 0.44), CM, ACM, MI, TVR, TLR, BLD, and LLL, compared to DES placement in random-effects model. Conclusions: The present systematic review and meta-analysis showed the feasibility of PCB angioplasty for the de novo lesions in patients with ACS in comparison with DES placement by the emergent procedures.

3.
Circ Rep ; 5(4): 123-132, 2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37025938

RESUMO

Background: The prognostic impact of CHADS2, CHA2DS2-VASc, and CHA2DS2-VASc-HS scores on clinical outcomes after drug-eluting stent (DES) placement has not been fully elucidated. Methods and Results: The present study was a retrospective, non-randomized, single-center, and lesion-based study. Target lesion failure (TLF), comprising cardiac death, non-fatal myocardial infarction, and target vessel revascularization, occurred in 7.1% of 872 consecutive de novo coronary lesions in 586 patients. These patients were electively and exclusively treated by DESs from January 2016 to January 2022 until July 2022 with a mean (±SD) observational interval of 411±438 days. Multivariate Cox proportional hazard analysis revealed that CHA2DS2-VASc-HS scores ≥7 (hazard ratio [HR] 1.800; 95% CI 1.06-3.05; P=0.029) was a significant predictor of cumulative TLF among 24 variables evaluated. CHADS2 scores ≥2 (HR 3.213; 95% CI 1.32-7.80; P=0.010) and CHA2DS2-VASc scores ≥5 (HR 1.980; 95% CI 1.10-3.55; P=0.022) were also significant in the multivariate analysis. Pairwise comparisons of receiver operating characteristic curves for CHADS2 score ≥2, CHA2DS2-VASc score ≥5, and CHA2DS2-VASc-HS score ≥7 showed they were equivalent in terms of predicting the incidence of TLF, with areas under the curve of 0.568, 0.575, and 0.573, respectively. Conclusions: All 3 cardiocerebrovascular thromboembolism risk scores were strong predictors of the incidence of cumulative mid-term TLF after elective DES placement, with cut-off values of 2, 5, and 7, respectively, and equivalent prognostic impacts.

4.
Bull Tokyo Dent Coll ; 56(2): 113-20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26084999

RESUMO

We report bone augmentation for alveolar bone loss at the bottom of the nasal cavity in conjunction with simultaneous implant placement in the same operative field in the esthetic zone. The patient was a 33-year-old man who was referred to us requesting implant treatment after undergoing tooth extraction (#12) due to root fracture. An examination was performed using cone beam computed tomography (CT) and simulation software. The results indicated insufficient volume of labial bone for the requested procedure, especially at the planned site of the implant neck. Therefore, bone augmentation was performed at the apical site of the implant socket (alveolar bone at the bottom of the nasal cavity). Because the surgical line of the harvest site formed a trapezoidal shape, the procedure was named the "Trapezial Design Technique". Assessment of complications (Barone & Covane classification), success (Albrektsson classification), and observation of labial bone using cone beam CT were performed postoperatively. No com-plications were observed at 27 months after prosthetic treatment. The implant and the tissue surrounding it were in a stable condition. This indicates that this procedure is effective in placing an implant with simultaneous bone augmentation in the esthetic zone.


Assuntos
Perda do Osso Alveolar/etiologia , Aumento do Rebordo Alveolar , Implantação Dentária Endóssea , Adulto , Transplante Ósseo , Estética , Humanos , Masculino
5.
Brain ; 132(Pt 3): 749-55, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19151081

RESUMO

Interventional paired associative stimulation (PAS) can induce plasticity in the cortex, and this plasticity was previously shown to be disordered in the primary motor cortex in focal hand dystonia (FHD). This study aimed to test whether associative plasticity is abnormal in the primary somatosensory cortex (S1) in FHD and whether PAS modulates excitatory or inhibitory interneurons within the cortex. Ten FHD patients and 10 healthy volunteers were studied. We investigated the changes in single- and double-pulse somatosensory-evoked potentials before and after PAS, which consisted of peripheral electrical nerve stimulation and subsequent transcranial magnetic stimulation over S1. Four sessions of somatosensory-evoked potentials recordings were performed: before PAS, and immediately, 15 and 30 min after PAS. We compared the time course of the somatosensory-evoked potentials between the FHD and healthy groups. In the single-pulse condition, the P27 amplitudes were significantly higher in FHD immediately after PAS than before PAS, while no changes were observed in healthy subjects. In the double-pulse condition, significant differences in the suppression ratio of P27 were found immediately after and 15 min after PAS, while there were no significant differences in healthy subjects. The P27 suppression tended to normalize toward the level of the healthy volunteer group. In FHD, PAS transiently induced an abnormal increase in excitability in S1. In addition, intracortical inhibition in S1 was found to increase as well. This abnormal plasticity of the intracortical neurons in S1 may contribute to the pathophysiology of dystonia.


Assuntos
Distúrbios Distônicos/fisiopatologia , Mãos/fisiopatologia , Plasticidade Neuronal/fisiologia , Córtex Somatossensorial/fisiopatologia , Adulto , Estimulação Elétrica/métodos , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inibição Neural/fisiologia , Desempenho Psicomotor/fisiologia , Estimulação Magnética Transcraniana/métodos
6.
Muscle Nerve ; 39(1): 101-5, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19086077

RESUMO

We report a patient with uncontrolled Crohn's disease who presented with progressive weakness of proximal muscles and a marked elevation of serum creatine kinase. Muscle biopsy from the left deltoid exhibited myositic changes with inflammatory infiltrates in the perimysium, endomysium, and perivascular locations. Most were stained as CD68-positive macrophages, whereas some were CD4- and CD8-positive T lymphocytes. Due to uncontrolled bowel inflammation, several fistulae were found in the descending colon, and partial colectomy was performed. An examination of the resected colon exhibited inflammation of the bowel structure surrounded mainly by CD68-positive macrophages. The histopathological findings of the descending colon were analogous to those of the muscle. After an increased dose of mesalazine and partial colectomy, her muscle symptoms improved. These findings suggest that the myositis in Crohn's disease is immune-mediated and that treatment of bowel inflammation should be emphasized as opposed to steroid or other immunosuppressive therapy.


Assuntos
Doença de Crohn/complicações , Doença de Crohn/patologia , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Miosite/patologia , Miosite/fisiopatologia , Adulto , Anti-Inflamatórios não Esteroides/administração & dosagem , Antígenos CD/imunologia , Antígenos de Diferenciação Mielomonocítica/imunologia , Biópsia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Colectomia , Colo/imunologia , Colo/patologia , Colo/fisiopatologia , Creatina Quinase/análise , Creatina Quinase/sangue , Doença de Crohn/cirurgia , Eletromiografia , Feminino , Humanos , Ativação Linfocitária/imunologia , Macrófagos/citologia , Macrófagos/imunologia , Imageamento por Ressonância Magnética , Mesalamina/administração & dosagem , Debilidade Muscular/imunologia , Debilidade Muscular/patologia , Debilidade Muscular/fisiopatologia , Músculo Esquelético/imunologia , Miosite/imunologia , Músculos do Pescoço/imunologia , Músculos do Pescoço/patologia , Músculos do Pescoço/fisiopatologia , Resultado do Tratamento
7.
Neuroimage ; 43(1): 128-35, 2008 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-18672075

RESUMO

To clarify the topography of the areas representing whole intraoral structures and elucidate bilateral neuronal projection to those areas in the primary somatosensory (S1) cortex, we recorded somatosensory-evoked magnetic fields (SEFs), which reflect the earliest cortical responses to pure tactile stimulation, using magnetoencephalography and a piezo-driven tactile stimulation device. Subjects consisted of 10 healthy male adults. Following tactile stimulation of 6 sites on the oral mucosa (inferior/superior buccal mucosa, posterior/anterior tongue mucosa, and upper/lower lip mucosa), SEFs with a peak latency of 15 ms (1M) were identified bilaterally. In contrast, SEFs with a peak latency of 30 ms following right index finger tactile stimulation were identified only in the contralateral hemisphere. Equivalent current dipoles (ECDs) generating 15 ms components were found along the posterior wall of the central sulcus, bilaterally. The ECD locations for oral mucosa-representing areas were located inferiorly to those for the index finger, with the following pattern of organization from top to bottom along the central sulcus: index finger, upper or lower lip, anterior or posterior tongue and superior or inferior buccal mucosa, with a wide distribution, covering 30% of the S1 cortex. Source strength for 1M in the ipsilateral hemisphere was weaker than that in the contralateral hemisphere. These results clearly indicate that sensory afferents innervating the intraoral region project to both the contralateral and ipsilateral 3b areas via the trigeminothalamic tract, where contralateral projection is predominant. The results clarify the intraoral structure-representing areas in the S1 cortex, adding those areas to the classical "sensory homunculus".


Assuntos
Mapeamento Encefálico/métodos , Potenciais Somatossensoriais Evocados/fisiologia , Boca/fisiologia , Córtex Somatossensorial/fisiologia , Tato/fisiologia , Adulto , Humanos , Masculino , Boca/inervação
8.
Neuroimage ; 42(2): 858-68, 2008 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-18585060

RESUMO

Primary somatosensory cortex (SI) and posterior parietal cortex (PPC) are activated by noxious stimulation. In neurophysiological studies using magnetoencephalography (MEG), however, it has been difficult to separate the activity in SI from that in PPC following stimulation of the upper limb, since the hand area of SI is very close to PPC. Therefore, we investigated human pain processing using MEG following the application of a thulium-YAG laser to the left thigh to separate the activation of SI and PPC, and to clarify the time course of the activities involved. The results indicated that cortical activities were recorded around SI, contralateral secondary somatosensory cortex (cSII), ipsilateral secondary somatosensory cortex (iSII), and PPC between 150-185 ms. The precise location of PPC was indicated to be the inferior parietal lobule (IPL), corresponding to Brodmann's area 40. The mean peak latencies of SI, cSII, iSII and IPL were 152, 170, 181, and 183 ms, respectively. This is the first study to clarify the time course of the activities of SI, SII, and PPC in human pain processing using MEG.


Assuntos
Potenciais Somatossensoriais Evocados , Lasers , Magnetoencefalografia/métodos , Dor/fisiopatologia , Estimulação Física/métodos , Córtex Somatossensorial/fisiopatologia , Coxa da Perna/fisiopatologia , Adulto , Humanos , Masculino , Coxa da Perna/inervação
9.
Mov Disord ; 23(4): 558-65, 2008 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-18074393

RESUMO

Somesthetic temporal discrimination (STD) is impaired in focal hand dystonia (FHD). We explored the electrophysiological correlate of the STD deficit to assess whether this is due to dysfunction of temporal inhibition in the somatosensory inhibitory pathway or due to dysfunction in structures responsible for nonmodality-specific timing integration. Eleven FHD patients and 11 healthy volunteers were studied. STD threshold was investigated as the time interval required for perceiving a pair of stimuli as two separate stimuli in time. We also examined the somatosensory-evoked potential (SEP) in a paired-pulse paradigm. We compared STD threshold and recovery function of SEP between the groups. STD thresholds were significantly greater in FHD than in healthy volunteers. The amount of P27 suppression in the 5 ms-ISI condition was significantly less in FHD. It was also found that the STD threshold and P27 suppression were significantly correlated: the greater the STD threshold, the less the P27 suppression. Significantly less suppression of P27 with a lack of significant change in N20 indicates that the impairment of somatosensory information processing in the time domain is due to dysfunction within the primary somatosensory cortex, suggesting that that the STD deficit in FHD is more attributable to dysfunction in the somatosensory pathway.


Assuntos
Distonia/fisiopatologia , Mãos/fisiopatologia , Inibição Neural/fisiologia , Córtex Somatossensorial/fisiopatologia , Adulto , Percepção Auditiva/fisiologia , Avaliação da Deficiência , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vias Neurais/fisiopatologia , Índice de Gravidade de Doença , Tálamo/fisiopatologia , Percepção do Tempo/fisiologia , Percepção Visual/fisiologia
10.
Clin Neurophysiol ; 118(2): 403-11, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17095288

RESUMO

OBJECTIVE: To establish an objective two-point discrimination test using magnetoencephalography (MEG). METHODS: First, we determined the discrimination threshold (DT) of the two-points. In the first experiment, we applied 0.9DT as standard stimuli, and 0.8DT, 1.1DT and 2DT as deviant stimuli in Conditions 1, 2 and 3, respectively. In the second experiment, we used 2DT and 0.9DT as the standard and deviant stimuli, respectively, in Condition 1. We applied two-stimuli that subjects felt as definitely one point or two-points in Condition 2 and 3, respectively. RESULTS: In the first experiment, the components peaking around 30-70 and 150-250ms following deviant stimuli were significantly larger than those following standard stimuli. Considering the peak latency, these components seem consistent with the magnetic mismatch field (MMF). In the second experiment, the MMF was recorded only in Condition 1. Therefore, it is considered that the MMF was recorded only when subjects automatically discriminate one point from two-points stimuli. CONCLUSIONS: This novel method can be used in neurophysiological two-point discrimination tests without the need to rely on the examiners' skills and subjects' reactions. SIGNIFICANCE: We confirmed that our new method could be used for the objective examination of two-point spatial discrimination.


Assuntos
Discriminação Psicológica/fisiologia , Eletrodiagnóstico/métodos , Magnetoencefalografia/métodos , Tato/fisiologia , Adulto , Vias Aferentes/fisiologia , Mapeamento Encefálico/métodos , Estimulação Elétrica , Eletrodiagnóstico/instrumentação , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Masculino , Mecanorreceptores/fisiologia , Exame Neurológico/instrumentação , Exame Neurológico/métodos , Transtornos da Percepção/diagnóstico , Transtornos da Percepção/fisiopatologia , Valor Preditivo dos Testes , Tempo de Reação/fisiologia , Pele/inervação , Córtex Somatossensorial/anatomia & histologia , Córtex Somatossensorial/fisiologia
11.
Clin Neurophysiol ; 117(8): 1669-76, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16798081

RESUMO

OBJECTIVE: We investigated the effect of the inhibitory process with increasing muscle force on event-related potentials (ERPs) and motor evoked potentials (MEPs). METHODS: The subjects performed a S1-S2 paradigm with go/nogo tasks. S1 was an auditory tone burst, and S2 was an electrical stimulation applied to the second (go stimuli) or fifth digit (nogo stimuli) of the left hand. The recordings were conducted at 3 force levels; 10, 30 and 50% maximal voluntary contraction (MVC). After the presentation of S2, the subjects were instructed to adjust their force level to match the target line with a force trajectory line in only the go trials. RESULTS: Nogo-N140 was significantly more negative in amplitude than go-N140 in all conditions, and became larger with increasing muscle force. The MEP, which was recorded at 150 ms after S2, became significantly smaller with increasing muscle force in nogo trials, whereas it became larger in go trials. CONCLUSIONS: Our results indicated that stronger inhibitory cerebral activity was needed for a nogo stimulus, in the case where a stronger response was needed for a go stimulus. SIGNIFICANCE: The present study showed a significant relationship between cortical inhibitory process and muscle force.


Assuntos
Encéfalo/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Desempenho Psicomotor/fisiologia , Estimulação Acústica , Adulto , Estimulação Elétrica , Potenciais Evocados , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Estimulação Magnética Transcraniana
12.
Neurosci Lett ; 397(3): 318-22, 2006 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-16406341

RESUMO

Nogo-related brain potentials may not be dependent on sensory modalities but reflect common neural activities specific to the inhibitory process. Recent studies reported that nogo potentials were elicited by not only visual and auditory but also somatosensory stimulation. However, the characteristics of this nogo potential evoked by somatosensory stimulation have been unclear because of the small number of reports. In the present study, therefore, to determine the characteristics of this potential, the effects of stimulus site and response hand were investigated. Electrical stimulation was delivered to the second and fifth digit of one hand, and the subjects had to respond to a go stimulus by pushing a button with the thumb contralateral to the stimulated side as quickly as possible. The amplitudes of the nogo-N140 component (N140 evoked by the nogo stimuli), which is very similar to the nogo-N2 components following visual and auditory stimulation, were unrelated to the stimulated digits, the second and fifth digit of the left and right hand. However, differences between go and nogo ERPs were significantly larger in the hemisphere contralateral to the response hand than the ipsilateral hemisphere. This result was inconsistent with visual and auditory go/nogo studies showing a right-hemisphere dominance or bilateral activities in nogo trials. Therefore, nogo-N140 should be considered to reflect the inhibitory process especially in the hemisphere contralateral to the response hand and the sensory modality dependency of nogo potentials.


Assuntos
Encéfalo/fisiologia , Potenciais Somatossensoriais Evocados , Estimulação Acústica , Adulto , Estimulação Elétrica , Eletroencefalografia , Feminino , Humanos , Masculino , Estimulação Luminosa , Desempenho Psicomotor
13.
Cereb Cortex ; 16(9): 1289-95, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16280463

RESUMO

Event-related functional magnetic resonance imaging was used to investigate brain processing of the signals ascending from peripheral C and Adelta fibers evoked by phasic laser stimuli on the right hand in humans. The stimulation of both C and Adelta nociceptors activated the bilateral thalamus, bilateral secondary somatosensory cortex, right (ipsilateral) middle insula, and bilateral Brodmann's area (BA) 24/32, with the majority of activity found in the posterior portion of the anterior cingulate cortex (ACC). However, magnitude of activity in the right (ipsilateral) BA32/8/6, including dorsal parts in the anterior portion of the ACC (aACC) and pre-supplementary motor area (pre-SMA), and the bilateral anterior insula was significantly stronger following the stimulation of C nociceptors than Adelta nociceptors. It was concluded that the activation of C nociceptors, related to second pain, evokes different brain processing from that of Adelta nociceptors, related to first pain, probably due to the differences in the emotional and motivational aspects of either pain, which are mainly related to the aACC, pre-SMA, and anterior insula.


Assuntos
Vias Aferentes/fisiopatologia , Encéfalo/fisiopatologia , Potenciais Somatossensoriais Evocados , Fibras Nervosas Amielínicas , Rede Nervosa/fisiopatologia , Dor/fisiopatologia , Adulto , Mapeamento Encefálico , Giro do Cíngulo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino
14.
Eur J Neurosci ; 21(9): 2555-62, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15932613

RESUMO

Synchronization and desynchronization of the neural rhythm in the brain play an important role in the orchestration of perception, motor action and conscious experience. Based on the results of electrocorticographic and magnetoencephalographic (MEG) recordings, it has been considered that human rolandic oscillations originate in the anterior bank of the central sulcus (20-Hz rhythm) and the postcentral cortex (10-Hz rhythm): the 20-Hz oscillation is closely related to motor function, while the 10-Hz rhythm is attributed mainly to sensory function. To test whether the rolandic oscillations are functionally relevant to the motor cortical excitability, we examined effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) of the left primary motor cortex (M1) on movement-related changes of the rolandic oscillations in 12 normal subjects. MEG data recorded during brisk extension of the right index finger in two different sessions (with and without rTMS conditioning) were compared. Motor-evoked potential (MEP) of the right hand muscle was also measured before and after rTMS to assess the motor cortical excitability. We found that 1-Hz rTMS over M1 significantly reduced the movement-related rebound of the 20-Hz oscillation in association with decreased motor cortical excitability. In particular, movement-related rebound of the 20-Hz rhythm was closely tied with motor cortical excitability. These findings further strengthen the notion of functional relevance of 20-Hz cortical oscillation to motor cortical excitability. In the framework of previous studies, the decrease in movement-related rebound may be regarded as a compensatory reaction to the inhibited cortical activity.


Assuntos
Magnetoencefalografia , Córtex Motor/fisiologia , Movimento/fisiologia , Periodicidade , Adulto , Sincronização Cortical , Estimulação Elétrica , Feminino , Dedos/inervação , Dedos/fisiologia , Humanos , Magnetismo , Masculino
15.
Clin Neurophysiol ; 116(4): 743-63, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15792883

RESUMO

OBJECTIVE: We reviewed the recent progress in electrophysiological studies using electroencephalography (EEG), magnetoencephalography (MEG) and repetitive transcranial magnetic stimulation (rTMS) on human pain perception. METHODS: For recording activities following A delta fiber stimulation relating to first pain, several kinds of lasers such as CO2, Tm:YAG and argon lasers are now widely used. The activity is frequently termed laser evoked potential (LEP), and we reviewed previous basic and clinical reports on LEP. We also introduced our new method, epidermal stimulation (ES), which is useful for recording brain activities by the signals ascending through A delta fibers. For recording activities following C fiber stimulation relating to second pain, several methods have been used but weak CO2 laser stimuli applied to tiny areas of the skin were recently used. RESULTS: EEG and MEG findings following C fiber stimulation were similar to those following A delta fiber stimulation except for a longer latency. Finally, we reviewed the effect of rTMS on acute pain perception. rTMS alleviated acute pain induced by intracutaneous injection of capsaicin, which activated C fibers, but it enhanced acute pain induced by laser stimulation, which activated A delta fibers. CONCLUSIONS: One promising approach in the near future is to analyze the change of a frequency band. This method will probably be used for evaluation of continuous tonic pain such as cancer pain, which evoked response studies cannot evaluate.


Assuntos
Medição da Dor/métodos , Dor/fisiopatologia , Percepção/fisiologia , Encéfalo/fisiologia , Eletrofisiologia , Humanos
16.
Muscle Nerve ; 31(4): 516-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15660376

RESUMO

In chorea-acanthocytosis, a neurological disorder associated with multisystem degeneration, amyotrophy and peripheral neuropathy are sometimes conspicuous. We describe a patient with chorea-acanthocytosis who showed distributed nemaline rods in biopsied muscle. It has been suggested that in chorea-acanthocytosis, the muscle membranous structures are disordered, and our finding may be attributable to this underlying myopathic condition.


Assuntos
Coreia/patologia , Miopatias da Nemalina/patologia , Adulto , Coreia/fisiopatologia , Feminino , Humanos , Miopatias da Nemalina/fisiopatologia , Condução Nervosa/fisiologia
17.
Exp Brain Res ; 162(3): 293-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15599719

RESUMO

The present study investigated the characteristics of the middle-latency negative potential of event-related potentials (ERPs) using somatosensory go/nogo tasks. We manipulated interstimulus interval (ISI) in Experiment 1 and stimulus probability in Experiment 2 and analyzed the subtracted difference waveform resulting from subtraction of the ERP evoked by the go stimulation from that evoked by the nogo stimulation. In Experiment 1, the peak latency of negativity became significantly longer as the ISI increased, but the peak amplitude was unchanged. The reaction time (RT) was longer with increasing ISI. In Experiment 2, manipulation of the stimulus probability yielded an increase in peak amplitude with decreasing probability of the nogo stimulus, but did not affect the latency. The RT increased as the probability of a nogo stimulus rose. Because manipulation of the ISI and stimulus probability elicited different brain activities, we hypothesized that manipulation of the ISI elicited a delay of the stimulus evaluation process including response inhibition, and that stimulus probability significantly affected the strength of the response inhibition process.


Assuntos
Tomada de Decisões/fisiologia , Potenciais Evocados/fisiologia , Inibição Neural/fisiologia , Tempo de Reação/fisiologia , Córtex Somatossensorial/fisiologia , Tato/fisiologia , Adulto , Cognição/fisiologia , Estimulação Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Probabilidade
18.
Clin Neurophysiol ; 115(8): 1875-84, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15261866

RESUMO

OBJECTIVE: To elucidate the temporal features of the cognitive process in two-point discrimination (TPD). METHODS: We measured somatosensory event-related potentials (ERPs) in 9 subjects during the TPD task, in which we provided a pair of electrical pulses simultaneously, altering the distance between the electrodes. We analyzed the TPD-related ERPs and investigated the relationship between the potentials and the subjects' judgments. RESULTS: During the TPD task, a negative potential approximately 140 ms after the stimulation (N140) was enhanced as compared to a stimulus counting task. Two late positive components, LPC-1 and LPC-2, whose peak latencies were 300 and 500 ms, respectively, were identified only in the TPD task. The LPC-1 was recorded dominantly in the fronto-central area, while the LPC-2 was detected dominantly in the centro-parietal area. The amplitude of the LPC-2 was significantly modulated by the degree of consistency in the subjects' judgment. On the other hand, these ERP components did not show significant difference between the alternate judgments, i.e. 'one-point' or 'two-point' judgment. CONCLUSIONS: Our results suggest that the N140 is related to the attention toward the stimulation. The LPC-1 and LPC-2 are likely to correspond to the processes represented by P3a and P3b, based on their temporal and spatial behavior.


Assuntos
Cognição/fisiologia , Discriminação Psicológica/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Adulto , Análise de Variância , Estimulação Elétrica/métodos , Humanos , Masculino
19.
Cereb Cortex ; 14(8): 851-7, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15054058

RESUMO

Although numerous anatomical and electrophysiological findings in animal studies have supported a hierarchical scheme of somatosensory processing, precise activation timings of each cortical area are not known. Therefore we examined the temporal relationship of activities among multiple cortical areas using magnetoencephalography in humans. We found activations in Brodmann's areas 3b, 4, 1, 5 and the secondary somatosensory cortex region in the right hemisphere following transcutaneous electrical stimulation of the dorsum of the left hand. The mean onset latencies of each cortical activity were 14.4, 14.5, 18.0, 22.4 and 21.7 ms, respectively. The differences of onset latencies among these activations indicated the serial mode of processing both through the postcentral gyrus and through the primary and secondary somatosensory cortices.


Assuntos
Algoritmos , Mapeamento Encefálico/métodos , Diagnóstico por Computador/métodos , Potenciais Somatossensoriais Evocados/fisiologia , Magnetoencefalografia/métodos , Córtex Somatossensorial/fisiologia , Adulto , Humanos
20.
Muscle Nerve ; 29(2): 243-7, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14755489

RESUMO

The temporal discrimination threshold (TDT) of various parts of the body was investigated in 35 healthy volunteers, and the effect of aging on the TDT was studied in 80 subjects (aged 18-82 years). Ascending (ATDT) and descending (DTDT) TDT values were measured in 13 areas using a pair of electrical stimuli. Both ATDT and DTDT differed significantly among the body parts (P < 0.01, one-way repeated ANOVA), and the TDT was shortest on the index finger and longest on the lower leg, where it was approximately 156% of that on the finger. There was no difference of the TDT value with gender or between sides. There was no effect of aging on the TDT in subjects aged 18-64 years, but the value was prolonged in subjects over 65 years. We suggest that the TDT difference among body parts is mainly due to the difference in sensory processes in the central nervous system, and that it may provide information about changes in the system related to aging.


Assuntos
Envelhecimento/fisiologia , Discriminação Psicológica/fisiologia , Limiar Sensorial/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estimulação Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas
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