19 research outputs found

    Neuroelectrical correlates of trustworthiness and dominance judgments related to the observation of political candidates

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    The present research investigates the neurophysiological activity elicited by fast observations of faces of real candidates during simulated political elections. We used simultaneous recording of electroencephalographic (EEG) signals as well as galvanic skin response (GSR) and heart rate (HR) as measurements of central and autonomic nervous systems. Twenty healthy subjects were asked to give judgments on dominance, trustworthiness, and a preference of vote related to the politicians' faces. We used high-resolution EEG techniques to map statistical differences of power spectral density (PSD) cortical activity onto a realistic head model as well as partial directed coherence (PDC) and graph theory metrics to estimate the functional connectivity networks and investigate the role of cortical regions of interest (ROIs). Behavioral results revealed that judgment of dominance trait is the most predictive of the outcome of the simulated elections. Statistical comparisons related to

    Evidence for Secretion of a Netrin-1-like Protein by Tetrahymena thermophila

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    Netrin-1 is a pleiotropic signaling molecule with targets in many mammalian cell types. Though first characterized as a chemotactic signal involved in neuronal guidance during development, netrin-1 has since been found to have a regulatory role in angiogenesis, and is also used as a biomarker in certain cancers. Tetrahymena thermophila are free-living protists that rely on chemotactic signals to find food, as well as to escape predators. Chemoattractants cause the cells to swim faster in the forward direction, while chemorepellents cause ciliary reversal, resulting in movement of the cell away from the noxious stimulus. We have previously found that netrin-1 is a chemorepellent in T. thermophila. More recently, we have detected netrin-1 by ELISA in both whole cell extract and secreted protein samples obtained from T. thermophila. In addition, we have immunolocalized netrin-1 staining to the cytosol of T. thermophila using an anti-netrin-1 antibody. We are currently running Western blots to determine the molecular weight of this protein and compare it to its vertebrate counterparts. Further experimentation is needed to determine the physiological role of this protein in T. thermophila

    From conformons to human brains: an informal overview of nonlinear dynamics and its applications in biomedicine

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    Methods of contemporary physics are increasingly important for biomedical research but, for a multitude of diverse reasons, most practitioners of biomedicine lack access to a comprehensive knowledge of these modern methodologies. This paper is an attempt to describe nonlinear dynamics and its methods in a way that could be read and understood by biomedical professionals who usually are not trained in advanced mathematics. After an overview of basic concepts and vocabulary of nonlinear dynamics, deterministic chaos, and fractals, application of nonlinear methods of biosignal analysis is discussed. In particular, five case studies are presented: 1. Monitoring the depth of anaesthesia and of sedation; 2. Bright Light Therapy and Seasonal Affective Disorder; 3. Analysis of posturographic signals; 4. Evoked EEG and photo-stimulation; 5. Influence of electromagnetic fields generated by cellular phones

    Effect of selected geometrical hole parameters on the flow intensity of oats grains

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    Przedstawiono wyniki badań pomiaru natężenia przepływu ziaren owsa o zmiennej zawartości wody przez otwory poziome o różnej średnicy i położeniu. Zawartość wody w ziarnach owsa wynosiła 0,089; 0,124 i 0,138 kg·(kg s.m.)-1. Zastosowano otwory okrągłe o średnicy Od 4,0 do 16cm, położone osiowo i niecentrycznie. Badania przeprowadzono w skali laboratoryjnej. Uzyskane wyniki badań poddano analizie statystycznej. Wykazała ona, że na objętościowe natężenie przepływu istotny wpływ wywierają średnica i położenie otworu oraz średnica równoważna ziarna owsa. Opracowano matematyczny model badanego procesu.The results of study on flow intensity of the oat grains of variable moisture content through the horizontal holes of different diameter and position were presented in the paper. The moisture contents (dry basis) of oat grains were 0.089; 0.124 and 0.138 kg/kg d.m. Round holes of the diameters ranging from 4 to 16 cm, in axial and concentric position were applied. The bests were carried out on laboratory scale and obtained results were carried out on laboratory scale and obtained results were statistically analyzed. It was found that the values of measured flow intensity (by volume) were significantly affected by size and position of the holes, moisture content and equivalent diameter of the oat grains. Obtained results were compared to the values calculated on the basis of ASAE D274,1

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    Neuronal electrical ongoing activity as a signature of cortical areas

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    Brodmann’s pioneering work resulted in the classification of cortical areas based on their cytoarchitecture and topology. Here, we aim at documenting that diverse cortical areas also display different neuronal electric activities. We investigated this notion in the hand-controlling sections of the primary somatosensory (S1) and motor (M1) areas, in both hemispheres. We identified S1 and M1 in 20 healthy volunteers by applying functional source separation (FSS) to their recorded electroencephalograms (EEG). Our results show that S1 and M1 can be clearly differentiated by their neuroelectric activities in both hemispheres and independently of the subject’s state (i.e., at rest or performing movements or receiving external stimulations). In particular, S1 displayed higher relative power than M1 in the alpha and low beta frequency ranges (8–25 Hz, p < .003), whereas the opposite occurred in the high gamma band (52–90 Hz, p = .006). In addition, S1’s activity had a smaller Higuchi’s fractal dimensions (HFD) than M1’s (p < .00001) in all subjects, permitting a reliable classification of the two areas. Moreover, HFD of M1’s activity resulted correlated with the hand’s fine motor control, as expressed by the 9-hole peg test scores. The present work is a first step toward the identification and classification of brain cortical areas based on neuronal dynamics rather than on cytoarchitectural features. We deem this step to be an improvement of our knowledge of the brain’s structural–functional unity

    Modeling the effects of extracortical sources on the EEG-signal

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