Secondary somatosensory area is involved in vibrotactile temporal-structure processing: MEG analysis of slow cortical potential shifts in humans

Abstract

Purpose: Temporal-structure discrimination is an essential dimension of tactile processing. Exploring object surface by touch generates vibrotactile input with various temporal dynamics, which gives diversity to tactile percepts. Here, we examined whether slow cortical potential shifts (SCPs) (<1?Hz) evoked by long vibrotactile stimuli can reflect active temporal-structure processing.

Materials and methods: Vibrotactile-evoked magnetic brain responses were recorded in 10 right-handed healthy volunteers using a piezoelectric-based stimulator and whole-head magnetoencephalography. A series of vibrotactile train stimuli with various temporal structures were delivered to the right index finger. While all trains consisted of identical number (15) of stimuli delivered within a fixed duration (1500?ms), temporal structures were varied by modulating inter-stimulus intervals (ISIs). Participants judged regularity/irregularity of ISI for each train in the active condition, whereas they ignored the stimuli while performing a visual distraction task in the passive condition. We analysed the spatiotemporal features of SCPs and their behaviour using the minimum norm estimates with the dynamic statistical parametric mapping.

Results: SCPs were localized to contralateral primary somatosensory area (S1), contralateral superior temporal gyrus, and contralateral as well as ipsilateral secondary somatosensory areas (S2). A significant enhancement of SCPs was observed in the ipsilateral S2 (S2i) in the active condition, whereas such effects were absent in the other regions. We also found a significant larger amplitude difference between the regular- and irregular-stimulus evoked S2i responses during the active condition than during the passive condition.

Conclusions: This study suggests that S2 subserves the temporal dimension of vibrotactile processing.     

Preparative separation of amino acid enantiomers as N-TFA,O-isopropyl derivatives by continuous countercurrent gas-liquid chromatography

Preparative separation of derivatives of amino acid enantiomers was carried out by a countercurrent gas–liquid chromatography (CCGLC) with chiral liquid phases, N-stearoyl-L -valine tert-butylamide and/or N-stearoyl-L -leucine tert-butylamide. In order to make effective use of these phases and also to lower the viscosity, Apiezon C was added as diluent. Through a repeated operation of a temperature gradient, purities more than 99% of leucine and α-amino butyric acid derivatives were proved to be obtained. © 1993 Wiley-Liss, Inc.     

Differentiation of Coxiella burnetii by Sequence Analysis of the Gene (com1) Encoding a 27-kDa Outer Membrane Protein

The gene (com1) encoding a 27-kDa outer membrane protein in 21 strains of Coxiella burnetii from a variety of clinical and geographical sources was sequenced for strain differentiation. The com1 gene was highly conserved among all the strains tested but there were several differences in nucleotide and deduced amino acid sequences. Based on the com1 gene-specific nucleotides and deduced amino acids, the 21 strains were divided into four groups. Group 1 contained 14 strains originating from ticks, cattle and human cases of acute Q fever. Groups 2 and 3 included 2 and 3 strains, respectively, originating from human cases of chronic Q fever. Group 4 contained 2 strains originating from a human case of acute Q fever and a goat with abortion. The results indicated that the strains originating from ticks, cattle and human cases of acute Q fever differed at the molecular level from those of human chronic Q fever. This study suggests that a sequence analysis of the com1 gene can be used for strain differentiation of C. burnetii.     

Near-UV Irradiation Induces Shock Proteins in Anacystis nidulans R-2; Possible Role of Active Oxygen

Anacystis nidulans R-2 cells were irradiated with near-UV light(295–390 nm) at an intensity that resulted in 30–40%survival. The near-UV light induced the preferential synthesisof sixteen proteins, which were designated UV-shock proteins.Several UV-shock proteins were also induced by heat shock (42?C)and six were synthesized by treatment with methyl viologen.The water-soluble fraction prepared from the cells generatedsuperoxide anion radicals upon irradiation with near-UV light,suggesting the production of active species of oxygen in cellsas a result of exposure to near-UV light. (Received February 18, 1991; Accepted May 24, 1991)     

A new aging technique by UV light observation of burnt otoliths for the conger eel Conger myriaster (Brevoort)

A new aging method, fluorescent observation of burnt otoliths, was discovered to disclose the age and growth of the conger eel. Under UV light, bright fluorescent zones were visible in the burnt otolith but not in the unburnt otolith. An illumination wavelength around 380 nm was found to be suitable for fluorescence observation of burnt otoliths. Bright zones of the conger eel otolith formed around June–August in Sendai Bay and were validated as annuli. The conger eels caught by net pot fishery were found to be mainly aged from 1+ to 4+ years. Received: March 7, 2001 / Revised: September 12, 2001 / Accepted: October 10, 2001     

Synthesis and biological evaluation of substituted imidazoquinoline derivatives as mPGES-1 inhibitors

We have previously reported 7-bromo-2-(2-chrolophenyl)-imidazoquinolin-4(5H)-one (1) as a novel potent mPGES-1 inhibitor. To clarify the essential functional groups of 1 for inhibition of mPGES-1, we investigated this compound structure–activity relationship following substitution at the C(4)-position and N-alkylation at the N(1)-, the N(3)-, and the N(5)-positions of 1. To prepare the target compounds, we established a good methodology for selective N-alkylation of the imidazoquinolin-4-one, that is, selective alkylation of 1 at the N(3)- and N(5)-positions was achieved by use of an appropriate base and introduction of a protecting group at the nitrogen atom in the imidazole part, respectively. Replacement of the C(4)-oxo group with nitrogen- or sulfur- linked substituents gave decreased inhibitory activity for mPGES-1, and introduction of alkyl groups on the nitrogen atom at the N(1)-, the N(3)-, and the N(5)-positions resulted in even larger loss of inhibitory activity. These results revealed that the C(4)-oxo group, and the hydrogen atoms at the N(5)-position and the imidazole part were the best substituents.     

Homozygosity mapping of the locus responsible for renal tubular dysplasia of cattle on bovine Chromosome 1

Renal tubular dysplasia is a hereditary disease of Japanese black cattle showing renal failure and growth retardation with an autosomal recessive trait. In the present study, we mapped the locus responsible for the disease (RTD) by linkage analysis with an inbred paternal half-sib pedigree obtained from commercial herds. By analyzing segregation of microsatellite markers in the half-sibs, significant linkage was observed between the RTD locus and markers on bovine Chromosome (Chr) 1 with the highest lod score of 11.4. Homozygosity mapping with the inbred pedigree further defined the localization of the RTD locus in a 4-cM region between microsatellite markers BMS4003 and INRA119. Mapping of the RTD locus on bovine Chr 1 will facilitate cloning and characterization of the gene responsible for this disease. Received: 24 September 1999 / Accepted: 14 December 1999