Grasping Hand Verbs: Oscillatory Beta and Alpha Correlates of Action-Word Processing

The grounded cognition framework proposes that sensorimotor brain areas, which are typically involved in perception and action, also play a role in linguistic processing. We assessed oscillatory modulation during visual presentation of single verbs and localized cortical motor regions by means of isometric contraction of hand and foot muscles. Analogously to oscillatory activation patterns accompanying voluntary movements, we expected a somatotopically distributed suppression of beta and alpha frequencies in the motor cortex during processing of body-related action verbs. Magnetoencephalographic data were collected during presentation of verbs that express actions performed using the hands (H) or feet (F). Verbs denoting no bodily movement (N) were used as a control. Between 150 and 500 msec after visual word onset, beta rhythms were suppressed in H and F in comparison with N in the left hemisphere. Similarly, alpha oscillations showed left-lateralized power suppression in the H-N contrast, although at a later stage. The cortical oscillatory activity that typically occurs during voluntary movements is therefore found to somatotopically accompany the processing of body-related verbs. The combination of a localizer task with the oscillatory investigation applied to verb reading as in the present study provides further methodological possibilities of tracking language processing in the brain.     

Effect of Ouabain Applied by Intrastriatal Microdialysis on the In Vivo Release of Dopamine, Acetylcholine, and Amino Acids in the Brain of Conscious Rats

In the present study we have applied a brain microdialysis technique to investigate the effects of ouabain infusion on the release of dopamine, acetylcholine, and amino acids from striatal neurons in freely moving rats. Ouabain caused an increase in the dialysate levels of dopamine; its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC); and the amino acids glutamate, aspartate, taurine, glycine, alanine, serine, asparagine, and threonine. The ouabain-induced increase in dopamine was dose dependent and explosive (100-fold at an infusion concentration of 1 mmol/L) and contrasted strongly with the small effect of the glycoside on the output of DOPAC. We investigated the nature of ouabain-induced transmitter release by determining its sensitivity to coinfusion with tetrodotoxin or the calcium antagonist Mg2+. In the case of dopamine two mechanisms of ouabain-induced release could be established. At lower infusion concentrations ouabain induced an exocytotic type of release whereas at higher concentrations the release was probably carrier mediated. In the case of amino acids we noticed a calcium-independent release which was nerve impulse flow dependent in the case of glutamate and aspartate and impulse flow independent in the case of alanine, serine, glycine, threonine, and asparagine. Ouabain induced a decrease in the release of acetylcholine and glutamine.     

Conformational analysis of m4(2)C-m4(2)C-m6(2)A: a chemically modified 3'-acceptor end of tRNA, studied by NMR and CD methods.

A study on the conformation of the title compound, C-C-A, and on its constituent dinucleotides is presented. 1H-NMR spectra at 360 and 500 MHz were completely assigned by decoupling experiments. Computer simulation of the spectra yielded precise proton-proton and proton-phosphorus coupling constant values. The coupling constants are analyzed in terms of torsion angles and of N- and S-type sugar pucker. 31P-NMR spectra gave some information about P-O backbone torsion angles alpha and zeta. CD spectroscopy was used to obtain insight in the base-base interaction. The C(1) and C(2) unit in C-C-A show normal preference for N-type conformation of the sugar ring, whereas the A(3) residue appears rather biased towards the S-conformation. The zeta and alpha backbone torsion angles in the C-C phosphodiester linkage in C-C-A appear to assume normal g-, g- conformation, the zeta, alpha combination in the C-A linkage is proposed to have a g+, t conformation. In the C-C fragment in C-C-A a regular stack is indicated; it is suggested that the C-A part adopts an unusual antiparallel base stack.     

HPLC conditions are critical for the detection of GABA by microdialysis

In microdialysis studies, neither exocytotic release of gamma-aminobutyric acid (GABA), nor the presence of GABA type B (GABA(B)) autoreceptors, have been clearly established. It was investigated whether the chromatographic separation of GABA may have contributed to discrepancies in the literature. After extending the profile of the HPLC chromatogram to a retention time of 60 min, it was observed that various unknown compounds of biological origin co-eluted near the GABA peak. The retention time of GABA appeared to be extremely sensitive to pH; even at a retention time of around 60 min there was only a small pH window (5.26 +/- 0.01) where GABA was consistently well separated from co-eluting compounds. GABA determined by the improved assay was sensitive to tetrodotoxin (TTX), calcium depletion and the GABA(B) autoreceptor agonist baclofen. The present results illustrate that if the proper analytical conditions are applied, extracellular GABA can be sampled and quantified by microdialysis in free-moving animals. However, when the time-curves are considered, there is a striking delay of about 15-30 min before the effects of TTX, calcium depletion or baclofen are observed, as compared to the reported response of neurotransmitters such as dopamine (less than 5 min). It is assumed that the glial cells serve as a buffer between the GABA synapse and the microdialysis probes. It is proposed that microdialysis samples measure synaptic GABA indirectly, through glial cells surrounding the synapses.     

Singing as a handicap: the effects of food availability and weather on song output in the Australian reed warbler Acrocephalus australis

Bird song is generally regarded as a sexually selected trait, and may represent a reliable handicap signal under at least certain conditions. Females may use the degree of male song production as a reliable cue to male condition or territory quality. We investigated the effect of supplementary feeding on song output in the migratory Australian reed warbler Acrocephalus australis . We experimentally increased the food availability on alternate days, and recorded several weather variables. We measured song rate and song length independently. Supplementary fed birds sang more on feeding days than on non-feeding days, while control birds did not show this effect. Song output was not significantly associated with any of the weather variables examined. Our results indicate that singing has the potential to serve as a reliable handicap signal to territorial food availability irrespective of the prevailing weather conditions. We discuss the role of energetic constraints and behavioural flexibility on the signaling function of song.     

Characterization of In Vivo Dopamine Release as Determined by Brain Microdialysis After Acute and Subchronic Implantations: Methodological Aspects

Infusion of tetrodotoxin (TTX) through the dialysis membrane and perfusion with calcium-free Ringer solution (calcium depletion) were used to evaluate the dopamine release determined by in vivo brain dialysis. Several hours after implantation, the dopamine release recorded by the U-shaped cannula did not respond to calcium depletion and was only partly (approximately 50%) TTX dependent. The half-life of the TTX-independent dopamine overflow was determined to be 2 h. In contrast, when a transstriatal cannula was used, the dopamine output displayed calcium and TTX dependency. Differences in the dimensions of the two types of probes are a likely explanation for the observed effects. Twenty-four hours after implantation, both types of cannula fulfilled the criteria of calcium and TTX dependency. The results indicate that infusion of TTX-containing or calcium-free Ringer solution can be used to estimate the functional damage caused by the implantation of the cannula.     

The Effect of Mixing Entire Male Pigs Prior to Transport to Slaughter on Behaviour,Welfare and Carcass Lesions

Research is needed to validate lesions recorded at meat inspection as indicators of pig welfare on farm. The aims were to determine the influence of mixing pigs on carcass lesions and to establish whether such lesions correlate with pig behaviour and lesions scored on farm. Aggressive and mounting behaviour of pigs in three single sex pens was recorded on Day −5, −2, and −1 relative to slaughter (Day 0). On Day 0 pigs were randomly allocated to 3 treatments (n = 20/group) over 5 replicates: males mixed with females (MF), males mixed with males (MM), and males unmixed (MUM). Aggressive and mounting behaviours were recorded on Day 0 at holding on farm and lairage. Skin/tail lesions were scored according to severity at the farm (Day −1), lairage, and on the carcass (Day 0). Effect of treatment and time on behaviour and lesions were analysed by mixed models. Spearman rank correlations between behaviour and lesion scores and between scores recorded at different stages were determined. In general, MM performed more aggressive behaviour (50.4 ± 10.72) than MUM (20.3 ± 9.55, P < 0.05) and more mounting (30.9 ± 9.99) than MF (11.4 ± 3.76) and MUM (9.8 ± 3.74, P < 0.05). Skin lesion scores increased between farm (Day −1) and lairage (P < 0.001), but this tended to be significant only for MF and MM (P = 0.08). There was no effect of treatment on carcass lesions and no associations were found with fighting/mounting. Mixing entire males prior to slaughter stimulated mounting and aggressive behaviour but did not influence carcass lesion scores. Carcass skin/tail lesions scores were correlated with scores recorded on farm (r_skin = 0.21 and r_tail = 0.18, P < 0.01) suggesting that information recorded at meat inspection could be used as indicators of pig welfare on farm.     

Green fluorescent chimeras indicate nonpolar localization of pullulanase secreton components PulL and PulM

The Klebsiella oxytoca pullulanase secreton (type II secretion system) components PulM and PulL were tagged at their N termini with green fluorescent protein (GFP), and their subcellular location was examined by fluorescence microscopy and fractionation. When produced at moderate levels without other secreton components in Escherichia coli, both chimeras were envelope associated, as are the native proteins. Fluorescent GFP-PulM was evenly distributed over the cell envelope, with occasional brighter foci. Under the same conditions, GFP-PulL was barely detectable in the envelope by fluorescence microscopy. When produced together with all other secreton components, GFP-PulL exhibited circumferential fluorescence, with numerous brighter patches. The envelope-associated fluorescence of GFP-PulL was almost completely abolished when native PulL was also produced, suggesting that the chimera cannot compete with PulL for association with other secreton components. The patches of GFP-PulL might represent functional secretons, since GFP-PulM also appeared in similar patches. GFP-PulM and GFP-PulL both appeared in spherical polar foci when made at high levels. In K. oxytoca, GFP-PulM was evenly distributed over the cell envelope, with few patches, whereas GFP-PulL showed only weak envelope-associated fluorescence. These data suggest that, in contrast to their Vibrio cholerae Eps secreton counterparts (M. Scott, Z. Dossani, and M. Sandkvist, Proc. Natl. Acad. Sci. USA 98:13978-13983, 2001), PulM and PulL do not localize specifically to the cell poles and that the Pul secreton is distributed over the cell surface.     

Prevalence of SCN1A-Related Dravet Syndrome among Children Reported with Seizures following Vaccination: A Population-Based Ten-Year Cohort Study

Objectives

To determine the prevalence of Dravet syndrome, an epileptic encephalopathy caused by SCN1A-mutations, often with seizure onset after vaccination, among infants reported with seizures following vaccination. To determine differences in characteristics of reported seizures after vaccination in children with and without SCN1A-related Dravet syndrome.

Methods

Data were reviewed of 1,269 children with seizures following immunization in the first two years of life, reported to the safety surveillance system of the Dutch national immunization program between 1 January 1997 and 31 December 2006. Selective, prospective follow-up was performed of children with clinical characteristics compatible with a diagnosis of Dravet syndrome.

Results

In 21.9% (n = 279) of children, a diagnosis of Dravet syndrome could not be excluded based on available clinical data (median age at follow-up 16 months). Additional follow-up data were obtained in 83.9% (n = 234) of these children (median age 8.5 years).15 (1.2% of 1,269; 95%CI:0.6 to 1.8%) children were diagnosed with SCN1A-related Dravet syndrome. Of all reported seizures following vaccinations in the first year of life, 2.5% (95%CI:1.3 to 3.6%) were due to SCN1A-related Dravet syndrome, as were 5.9% of reported seizures (95%CI:3.1 to 8.7%) after 2^nd or 3^rd DTP-IPV-Hib vaccination.Seizures in children with SCN1A-related Dravet syndrome occurred more often with a body temperature below 38.5°C (57.9% vs. 32.6%, p = 0.020) and reoccurred more often after following vaccinations (26.7% vs. 4.0%, p = 0.003), than in children without a diagnosis of SCN1A-related Dravet Syndrome.

Conclusions

Although Dravet syndrome is a rare genetic epilepsy syndrome, 2.5% of reported seizures following vaccinations in the first year of life in our cohort occurred in children with this disorder. Knowledge on the specific characteristics of vaccination-related seizures in this syndrome might promote early diagnosis and indirectly, public faith in vaccination safety.