Single Versus Repetitive Spiking to the Current Stimulus of A-β Mechanosensitive Neurons in the Crotaline Snake Trigeminal Ganglion

1. Intrasomal recordings of potentials produced by current stimulation in vivo were made from 24 (A-) touch and 19 vibrotactile neurons in the trigeminal ganglion of 29 crotaline snakes, Trimeresurus flavoviridis. 2. Usually touch neurons responded with a single action potential at the beginning of a prolonged depolarizing pulse, whereas all vibrotactile neurons responded with multiple spikes.3. The electrophysiological parameters examined were membrane potential, threshold current, input resistance and capacitance, time constant, rebound latency, and its threshold current. Touch neurons had higher input resistance (and lower input capacitance) than vibrotactile neurons.4. In conclusion, current injection, which elicits a single or multiple spiking, seems a useful way to separate touch neurons from vibrotactile neurons without confirming the receptor response, and some membrane properties are also specific to the sensory modality.     

Subcellular Distribution of α1 and β2/3 GABAA Receptor Subunits in Sensory Neurons of the Bovine Trigeminal Mesencephalic Nucleus: Evidence Suggesting Their Axoplasmic Transport

Neurons were free-hand isolated under the stereomicroscope from the bovine trigeminal mesencephalic nucleus. These neurons were challenged with monoclonal antibodies against the alpha1 and the beta2/3 subunits of the GABA(A) receptor. The neurons showed a strong reaction to both antibodies. The reaction was mainly intracellular in the round cell bodies and in the axoplasm of the axon emerging from these pseudounipolar cells. This suggests the synthesis of these subunits in the cell body and their transport along the axon.     

Spatial vs. Temporal Features in ICA of Resting-State fMRI – A Quantitative and Qualitative Investigation in the Context of Response Inhibition

Independent component analysis (ICA) can identify covarying functional networks in the resting brain. Despite its relatively widespread use, the potential of the temporal information (unlike spatial information) obtained by ICA from resting state fMRI (RS-fMRI) data is not always fully utilized. In this study, we systematically investigated which features in ICA of resting-state fMRI relate to behaviour, with stop signal reaction time (SSRT) in a stop-signal task taken as a test case. We did this by correlating SSRT with the following three kinds of measure obtained from RS-fMRI data: (1) the amplitude of each resting state network (RSN) (evaluated by the standard deviation of the RSN timeseries), (2) the temporal correlation between every pair of RSN timeseries, and (3) the spatial map of each RSN. For multiple networks, we found significant correlations not only between SSRT and spatial maps, but also between SSRT and network activity amplitude. Most of these correlations are of functional interpretability. The temporal correlations between RSN pairs were of functional significance, but these correlations did not appear to be very sensitive to finding SSRT correlations. In addition, we also investigated the effects of the decomposition dimension, spatial smoothing and Z-transformation of the spatial maps, as well as the techniques for evaluating the temporal correlation between RSN timeseries. Overall, the temporal information acquired by ICA enabled us to investigate brain function from a complementary perspective to the information provided by spatial maps.     

A Survey of the Cytology and Synaptic Organization of the Insular Trigeminal—Cuneatus Lateralis Nucleus in the Rat,Including an Identification of Spinal Afferent Inputs

The cytology and synaptic organization of the insular trigeminal—cuneatus lateralis (iV-Cul) nucleus was examined in the rat. In addition, the ultrastructural morphology and synaptic connectivity of anterogradely labeled spinal afferent axons terminating in iV-Cul were examined following injection of horseradish peroxidase (HRP) into the cervical spinal cord. The uniformity of the ultrastructural features of iV-Cul neurons supports the presence of a homogeneous neuronal population. The most prominent feature of the iV-Cul neuropil is the presence of numerous interdigitating astrocytic processes, which extensively isolate neuronal somata and processes. iV-Cul contains a heterogeneous population of axonal endings that can be separated into three categories, depending upon whether they contain predominantly spherical-shaped agranular synaptic vesicles (R endings), predominantly pleomorphic-shaped agranular synaptic vesicles (P endings), or a heterogeneous population of dense-core vesicles (DC endings). The R endings represent the majority of axonal endings in iV-Cul and establish asymmetrical axodendritic and axospinous synaptic contacts, primarily along the distal portions of the dendritic tree. P endings establish symmetrical axosomatic, axodendritic, and axospinous synaptic contacts and exhibit a more generalized distribution along the somadendritic tree. DC terminals establish asymmetrical axodendritic synaptic contacts with distal dendritic processes and are the least frequently observed endings in the iV-Cul neuropil. Numerous synaptic glomeruli, exhibiting a single large central R bouton that establishes multiple axodendritic or axospinous synapses, characterize the iV-Cul neuropil. Axoaxonic synapses are conspicuously absent from the iV-Cul neuropil and glomeruli. The anterograde HRP labeling of spinal afferent axons that terminate in iV-Cul indicates that the terminals along these fibers are of the R type and that they are engaged predominantly in synaptic glomeruli. The results of this study indicate that the synaptic organization of iV-Cul is distinctly different from that of neighboring somatosensory nuclei, and supports the recent suggestion that this nucleus should be considered a separate precerebellar spinal relay nucleus in the lateral medulla.     

Fast and Slow Readers of the Hebrew Language Show Divergence in Brain Response ～200 ms Post Stimulus: An ERP Study

Higher N170 amplitudes to words and to faces were recently reported for faster readers of German. Since the shallow German orthography allows phonological recoding of single letters, the reported speed advantages might have their origin in especially well-developed visual processing skills of faster readers. In contrast to German, adult readers of Hebrew are forced to process letter chunks up to whole words. This dependence on more complex visual processing might have created ceiling effects for this skill. Therefore, the current study examined whether also in the deep Hebrew orthography visual processing skills as reflected by N170 amplitudes explain reading speed differences. Forty university students, native speakers of Hebrew without reading impairments, accomplished a lexical decision task (i.e., deciding whether a visually presented stimulus represents a real or a pseudo word) and a face decision task (i.e., deciding whether a face was presented complete or with missing facial features) while their electroencephalogram was recorded from 64 scalp positions. In both tasks stronger event related potentials (ERPs) were observed for faster readers in time windows at about 200 ms. Unlike in previous studies, ERP waveforms in relevant time windows did not correspond to N170 scalp topographies. The results support the notion of visual processing ability as an orthography independent marker of reading proficiency, which advances our understanding about regular and impaired reading development.     

Comparison of Macular Integrity Assessment (MAIA ?), MP-3, and the Humphrey Field Analyzer in the Evaluation of the Relationship between the Structure and Function of the Macula

Purpose

This study was conducted in order to compare relationships between the macular visual field (VF) mean sensitivity measured by MAIA^TM (Macular Integrity Assessment), MP-3, or Humphry field analyzer (HFA) and the ganglion cell and inner plexiform layer (GCA) thicknesses.

Methods

This cross-sectional study examined 73 glaucoma patients and 19 normal subjects. All subjects underwent measurements for GCA thickness by Cirrus HD-OCT and static threshold perimetry using MAIA^TM, MP-3, or HFA. VF and OCT in the retinal view were used to examine both the global relationship between the VF sensitivity and GCA thickness, and the superior hemiretina and inferior hemiretina. The relationship between the GCA thickness and macular sensitivity was examined by Spearman correlation analysis.

Results

For each instrument, statistically significant macular VF sensitivity (dB) and GCA thickness relationships were observed using the decibel scale (R = 0.547–0.687, all P < 0.001). The highest correlation for the global (R = 0.682) and the superior hemiretina (R = 0.594) GCA thickness-VF mean sensitivity was observed by the HFA. The highest correlation for the inferior hemiretina (R = 0.687) GCA thickness-VF mean sensitivity was observed by the MP-3. Among the three VF measurement instruments, however, no significant differences were found for the structure-function relationships.

Conclusions

All three VF measurement instruments found similar structure-function relationships in the central VF.     

Statistical Comparison of Carcinogenic Effects and Dose–Response Relationships in Rats and Mice for 2,4-Toluene Diamine to those Ascribed to Toluene Diisocyanate

The U.S. National Toxicology Program (NTP) conducted 2-year bioassays of commercial grade toluene diisocyanate (TDI) (80% 2,4-TDI and 20% 2,6-TDI) and 2,4-toluene diamine (TDA) and concluded that both were carcinogenic in rodents. In the TDI study, there was an unproven but likely formation of TDA either because of flawed test-substance handling and storage conditions and/or the atypical exposure conditions employed. Although the carcinogenic responses in both studies were qualitatively similar, several statistical analyses were performed to substantiate this possibility more rigorously. Seven different statistical approaches combine to yield a robust and consistent conclusion that, if only a small fraction (approximately 5%) of the dose of TDI were hydrolyzed to TDA in the TDI study, then that would be sufficient to explain the observed carcinogenic responses in the TDI study.     

Role of LIM Kinase 1 in Dopaminergic and Serotonergic Neurons in Genome Stability,Learning and Memory during Stress Response to Weakening of Earth’s Magnetic Field in Drosophila

Journal of Evolutionary Biochemistry and Physiology - The paper continues the cycle of studies on the evolutionary link between the mechanisms of stress response formation and cognitive functions...     

Genetic Relationships between the G Protein β_entitystart_#947_entit Complex, Ste5p, Ste20p and Cdc42p: Investigation of Effector Roles in the Yeast Pheromone Response Pathway

The Saccharomyces cerevisiae G protein βγ dimer, Ste4p/Ste18p, acts downstream of the α subunit, Gpa1p, to activate the pheromone response pathway and therefore must interact with a downstream effector. Synthetic sterile mutants that exacerbate the phenotype of ste4-ts mutations were isolated to identify proteins that functionally interact with Ste4p. The identification of a ste18 mutant indicated that this screen could identify proteins that interact directly with Ste4p. The other mutations were in STE5 and the STE20 kinase gene, which act near Ste4p in the pathway, and a new gene called STE21. ste20 null mutants showed residual mating, suggesting that another kinase may provide some function. Overexpression of Ste5p under galactose control activated the pheromone response pathway. This activation was dependent on Ste4p and Ste18p and partially dependent on Ste20p. These results cannot be explained by the linear pathway of Ste4p -> Ste20p -> Ste5p. Overexpression of Cdc42p resulted in a slight increase in pheromone induction of a reporter gene, and overexpression of activated forms of Cdc42p resulted in a further twofold increase. Mutations in pheromone response pathway components did not suppress the lethality associated with the activated CDC42 mutations, suggesting that this effect is independent of the pheromone response pathway.     

Passive Detection of Biological Aerosols in the Atmosphere with a Fourier Transform Instrument (FTIR)—the Results of the Measurements in the Laboratory and in the Field

Fourier Transform Infrared Radiation (FTIR) spectroscopy is one of the most powerful methods for the detection of gaseous constituents, aerosols, and dust in planetary atmospheres. Infrared spectroscopy plays an important role in searching for biomarkers, organics and biological substances in the Universe. The possibility of detection and identifications with FTIR spectrometer of bio-aerosol spores (Bacillus atrophaeus var. globigii=BG) in the atmosphere is discussed in this paper. We describe the results of initial spectral measurements performed in the laboratory and in the field. The purpose of these experiments was to detect and to identify bio-aerosol spores in two conditions: 1) In a closed chamber where the thermal contrast between the background and aerosols was large, and 2) In open air where the thermal contrast between the background and aerosols was small. The extinction spectrum of BG spores was deduced by comparing our measurements with models, and other measurements known from the literature. Our theoretical and experimental studies indicate that, during passive remote sensing measurements, it is difficult-but possible to detect and to identify bio-aerosol clouds by their spectral signatures. The simple spectral analysis described in the paper can be useful for the detection of various kinds of trace aerosols-not only in the Earth's atmosphere, but also during planetary missions in the environments of other astronomical objects such as planets, comets etc. We expect that the interpretation of data from spectrometric sounding of Venus and Mars during the current missions Mars and Venus Express, and later during the Rosetta mission will benefit from our experimental work and numerical modelling.     

Fusarium toxins in bread cereals of the land Brandenburg in the years 2000 to 2004 — Comparison of integrated and ecological cultivation

Over a period of five years (2000–2004), wheat and rye samples of integrated and ecological cultivation in the land Brandenburg were analyzed by HPLC for theFusarium toxins deoxynivalenol and zearalenone. In the years 2000, 2001, 2003 and 2004 the contamination generally was lower than in the year 2002. In the five years of testing, the contamination byFusarium toxins was significantly less frequent and lower in cereals of ecological cultivation than in cereals of integrated cultivation. Presented at the 27^th Mykotoxin-Workshop, Dortmund, Germmany, June 13–15, 2005 Financial support: The Ministry of rural development, environment and consumer protection of the land Brandenburg     

Dopamine Inhibition of the Release of Endogenous Acetylcholine from Corpus Striatum and Cerebral Cortex in Tissue Slices and Synaptosomes: A Presynaptic Response?

Abstract: The effect of dopamine on the release of endogenous acetylcholine from striatal slices and synaptosomes and from cerebral cortex synaptosomes was studied. K⁺ (56 m M ) and veratrine (75 μM ) increased the release of acetylcholine from striatal slices by 3.7 and 3.3 times the resting release, respectively. The effect of veratrine was completely abolished by tetrodotoxin (1 μM ). Dopamine (10⁻⁶ to 10⁻³ M ) reduced the K⁺-evoked release of acetylcholine from striatal slices in a dose-dependent manner. The resting release of acetylcholine was also significantly reduced by dopamine. Apomorphine (20 μM ) significantly reduced the K⁺-evoked release of acetylcholine, and both this effect and the inhibition due to dopamine (1 m M ) were significantly antagonised by chlorpromazine (20 μM ). Dopamine had a similar effect on the release of acetylcholine from striatal synaptosome beds; the resting release was depressed 32% by the presence of dopamine (1 m M ). A greater effect of dopamine was seen on the release of acetylcholine from cerebral cortex synaptosome beds, the resting release being reduced by 54% and the K⁺-evoked release by 29%. These results are discussed in terms of the possible role of presynaptic dopamine receptors in controlling the release of acetylcholine and the magnitude of their contribution compared with that of the postsynaptic dopamine receptor.