Browsing by Subject "POTENTIALS"

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  • Jansson-Verkasalo, Eira; Ruusuvirta, Timo; Huotilainen, Minna; Alku, Paavo; Kushnerenko, Elena; Suominen, Kalervo; Rytky, Seppo; Luotonen, Mirja; Kaukola, Tuula; Tolonen, Uolevi; Hallman, Mikko (2010)
  • Alsufyani, Abdulmajeed; Harris, Kathryn; Zoumpoulaki, Alexia; Filetti, Marco; Bowman, Howard (2021)
    Studies have shown that presenting own-name stimuli on the fringe of awareness in Rapid Serial Visual Presentation (RSVP) generates a P3 component and provides an accurate and countermeasure resistant method for detecting identity deception (Bowman et al., 2013, 2014). The current study investigates how effective this Fringe-P3 method is at detecting recognition of familiar name stimuli with lower salience (i.e., famous names) than own name stimuli, as well as its accuracy with multi-item stimuli (i.e., first and second name pairs presented sequentially). The results demonstrated a highly significant ERP difference between famous and non-famous names at the group level and a detectable P3 for famous names for 86% of participants at the individual level. This demonstrates that the Fringe-P3 method can be used for detecting name stimuli other than own-names and for multi-item stimuli, thus further supporting the method's potential usefulness in forensic applications such as in detecting recognition of accomplices. (c) 2021 Elsevier Ltd. All rights reserved.
  • Islam, Mohammad Mahmudul; Pal, Shuvo; Hossain, Mohammad Mosarof; Mozumder, Mohammad Mojibul Hoque; Schneider, Petra (2020)
    By employing empirical and secondary data (qualitative and quantitative), this study demonstrates how social equity (with its three dimensions) can meaningfully address the conservation of the coastal social-ecological system (SES), without losing diverse ecosystem services (ES) in south-east coastal Bangladesh. Based on this proposition, this study assesses the available ES and identifies the drivers responsible for ES changes, arguing for the application of social equity for resource conservation. The findings show that communities along Bangladesh's south-eastern coast use several ES for food, medicine, income, livelihoods, and cultural heritage. However, this valuable ecosystem is currently experiencing numerous threats and stressors of anthropogenic and natural origin. In particular, large-scale development activities, driven by the blue growth agenda, and neoliberalism policy, pose a risk to the local communities by degrading coastal ecosystem services. Escaping this situation for coastal natural resource-dependent communities in Bangladesh will require a transformation in the governance structure. Implementing the Small-Scale Fisheries (SSF) Guidelines that call for initiating policy change to deliver social justice to small-scale fisheries would help to address coastal ecosystem service conservation in Bangladesh.
  • Smeds, Eero; Vanhatalo, Sampsa; Piitulainen, Harri; Bourguignon, Mathieu; Jousmaki, Veikko; Hari, Riitta (2017)
    Objective: Somatosensory evoked potentials have high prognostic value in neonatal intensive care, but their recording from infants is challenging. Here, we studied the possibility to elicit cortical responses in newborns by simple passive hand movements. Methods: We examined 13 newborns (postnatal age 1-46 days) during clinically indicated 19-channel electroencephalography (EEG) recordings in the neonatal intensive care unit; EEG indications included birth asphyxia and suspected epileptic seizures. The experimenter moved the infant's wrist or fingers at 1 or 2 Hz for 5-10 min, separately on both sides. We measured movement kinematics with an accelerometer attached to the infant's hand and computed coherence between the EEG and acceleration signals (corticokinematic coherence, CKC). Results: Statistically significant CKC (amplitude 0.020-0.511) with characteristic scalp topography was observed in all infants at twice the movement frequency. CKC was contralaterally dominant on the central scalp (median laterality index 0.48 for right-hand and -0.63 for left-hand movements). Conclusions: Passive movements elicit cortical responses that can be readily observed in clinical EEG recordings from newborns in the intensive-care environment. (C) 2017 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd.
  • Mason, D. R.; Sand, A. E.; Yi, X.; Dudarev, S. L. (2018)
    Recently we have presented direct experimental evidence for large defect clusters being formed in primary damage cascades in self-ion irradiated tungsten [Yi et al., EPL 110:36001 (2015)]. This large size is significant, as it implies that strong elastic interaction between the defects will affect their subsequent evolution, especially if defects are formed close together. Here we present a direct experimental observation of the separation between visible defects in self-ion irradiated tungsten, in the form of a 2d pairwise radial distribution function extracted from transmission electron micrographs (TEM). We also present a detailed analysis of the observed radial distribution function, and infer the probable size and shape of individual cascades. We propose and validate a simple exponential form for the spatial distribution of defects within a single cascade. The cascade statistics necessary have been acquired by developing an automated procedure for analysing black-dot damage in TEM micrographs. We confirm that the same model also produces a high-quality fit to the separation between larger defects observed in MD simulations. For the first time we present experimental evidence for the sub-nanometre-scale spatial distribution of defect clusters within individual cascades. (C) 2017 EURATOM. Published by Elsevier Ltd on behalf of Acta Materialia Inc. All rights reserved.
  • Kurki, Ilmari; Hyvarinen, Aapo; Henriksson, Linda (2022)
    Visual focal attention is both fast and spatially localized, making it challenging to investigate using human neu-roimaging paradigms. Here, we used a new multivariate multifocal mapping method with magnetoencephalog-raphy (MEG) to study how focal attention in visual space changes stimulus-evoked responses across the visual field. The observer's task was to detect a color change in the target location, or at the central fixation. Simulta-neously, 24 regions in visual space were stimulated in parallel using an orthogonal, multifocal mapping stimulus sequence. First, we used univariate analysis to estimate stimulus-evoked responses in each channel. Then we applied multivariate pattern analysis to look for attentional effects on the responses. We found that attention to a target location causes two spatially and temporally separate effects. Initially, attentional modulation is brief, observed at around 60-130 ms post stimulus, and modulates responses not only at the target location but also in adjacent regions. A later modulation was observed from around 200 ms, which was specific to the location of the attentional target. The results support the idea that focal attention employs several processing stages and suggest that early attentional modulation is less spatially specific than late.
  • Alsius, Agnes; Möttönen, Riikka; Sams, Mikko E.; Soto-Faraco, Salvador; Tiippana, Kaisa (2014)
  • Partanen, Juhani V.; Vanhanen, Jukka; Liljander, Sara K. (2022)
    In needle electromyography, there are two spontaneous waveforms, miniature end plate potentials and "end plate spikes", appearing usually together. Miniature end plate potentials are local, non-propagating postsynaptic waves, caused by spontaneous exocytosis of acetylcholine in the neuromuscular junction. The prevailing hypothesis states that "end plate spikes" are propagated postsynaptic action potentials of muscle fibers, caused by presynaptic irritation of the motor nerve or nerve terminal. Using several small concentric needle electrodes in parallel with the muscle fibers, most "end plate spikes" are strictly local or propagating for 2-4 mm. At the end plate zone, there are miniature end plate potentials without "end plate spikes". Local "end plate spikes" are junctional potentials of intrafusal gamma neuromuscular junctions of the nuclear bag fibers, and propagated "end plate spikes" are potentials of nuclear chain muscle fibers of muscle spindles. Miniature end plate potentials without "end plate spikes" at the end plate zone derive from alpha neuromuscular junctions. These findings contrast with the prevailing hypothesis. The history of observations and different hypotheses of the origin of end plate spikes are described.
  • Zhao, Qingjian; Ding, Sheng; Wen, Zuomin; Toppinen, Anne (2019)
    In the context of global climate change, energy conservation and greenhouse effect gases (GHG) reduction are major challenges to mankind. The forestry-pulp and paper industry is a typical high energy consumption and high emission industry. We conducted in-depth research on the energy flows and carbon footprint of the forestry-pulp paper industry. The results show that: (1) The main sources of energy supply include external fossil fuel coal and internal biomass fuel black liquor, which supply 30,057,300 GJ and 14,854,000 GJ respectively; in addition, the energy produced by diesel in material transportation reaches 11,624,256 GJ. (2) The main energy consumption processes include auxiliary engineering projects, material transportation, papermaking, alkali recovery, pulping and other production workshops. The percentages of energy consumption account for 26%, 18%, 15%, 10% and 6%, respectively. (3) The main sources of carbon include coal and forest biomass, reaching 770,000 tons and 1.39 million tons, respectively. (4) Carbon emissions mainly occur in fuel combustion in combined heating and power (CHP) and diesel combustion in material transportation, reaching 6.78 million tons and 790,000 tons of carbon, respectively. (5) Based on steam and electricity consumption, the indirect carbon emissions of various thermal and electric energy production units were calculated, and the key energy consumption process units and hotspot carbon flow paths were further found. This research established a theoretical and methodological basis for energy conservation and emission reduction.
  • Kostilainen, Kaisamari; Wikstrom, Valtteri; Pakarinen, Satu; Videman, Mari; Karlsson, Linnea; Keskinen, Maria; Scheinin, Noora M.; Karlsson, Hasse; Huotilainen, Minna (2018)
    We evaluated the feasibility of a multi-feature mismatch negativity (MMN) paradigm in studying auditory processing of healthy newborns. The aim was to examine the automatic change-detection and processing of semantic and emotional information in speech in newborns. Brain responses of 202 healthy newborns were recorded with a multi-feature paradigm including a Finnish bi-syllabic pseudo-word/ta-ta/as a standard stimulus, six linguistically relevant deviant stimuli and three emotionally relevant stimuli (happy, sad, angry). Clear responses to emotional sounds were found already at the early latency window 100-200 ms, whereas responses to linguistically relevant minor changes and emotional stimuli at the later latency window 300-500 ms did not reach significance. Moreover, significant interaction between gender and emotional stimuli was found in the early latency window. Further studies on using multi-feature paradigms with linguistic and emotional stimuli in newborns are needed, especially those containing of follow-ups, enabling the assessment of the predictive value of early variations between subjects.
  • Greenleaf, Allan; Kurylev, Yaroslav; Lassas, Matti; Uhlmann, Gunther (2008)
  • Zippel, Christoph; Israil, Roumany; Schüssler, Lars; Hassan, Zahid; Schneider, Erik K.; Weis, Patrick; Nieger, Martin; Bizzarri, Claudia; Kappes, Manfred M.; Riehn, Christoph; Diller, Rolf; Braese, Stefan (2021)
    The modular synthesis of Au(I)/Ru(II) decorated mono- and heterobimetallic complexes with pi-conjugated [2.2]paracyclophane is described. [2.2]Paracyclophane serves as a rigid spacer which holds the metal centers in precise spatial orientations and allows metal-to-metal distance modulation. A broad set of architectural arrangements of pseudo -geminal, -ortho, -meta, and -para substitution patterns were employed. Metal-to-metal distance modulation of Au(I)/Ru(II) heterobimetallic complexes and the innate transannular pi-communication of the cyclophanyl scaffold provides a promising platform for the investigations of structure-activity relationship and cooperative effects. The Au(I)/Ru(II) heterobimetallic cyclophanyl complexes are stable, easily accessible, and exhibit promising catalytic activity in the visible-light promoted arylative Meyer-Schuster rearrangement.
  • Antinmaa, Jaana; Lapinleimu, Helena; Salonen, Jaakko; Stolt, Suvi; Kaljonen, Anne; Jääskeläinen, Satu (2020)
    Aim: To study whether auditory function measured with brainstem auditory evoked potential and brainstem audiometry recordings in the neonatal period associates with language development 1 year later in preterm infants.Methods: This retrospective study included 155 preterm infants (birthweight ≤1500 g and/or birth ≤32 gestational weeks) born between 2007 and 2012 at the Turku University Hospital. Auditory function was recorded in neonatal period. Information of language development was gathered at the mean corrected age of 1 year by using the Finnish version of the MacArthur Communicative Development Inventory.Results: Slower auditory processing (longer interpeak interval, IPI I-V) in the right ear in the neonatal brainstem auditory evoked potential recording associated with smaller receptive lexicon size at 1 year (P = .043). Infants with longer IPI I-V were more likely to have a deviant (≤17 words) receptive lexicon size (P = .033). The ab-sence of a contralateral response with right ear stimulation increased the risk for deviant lexicon size (P = .049).Conclusion: The results suggest that impaired auditory function in the neonatal pe-riod in preterm infants may lead to a poorer receptive language outcome 1 year later. Auditory pathway function assessment provides information for the identification of preterm children at risk for weak language development.
  • Virtala, Paula; Partanen, Eino; Tervaniemi, Mari; Kujala, Teija (2018)
    To process complex stimuli like language, our auditory system must tolerate large acoustic variance, like speaker variability, and still be sensitive enough to discriminate between phonemes and to detect complex sound relationships in, e.g., prosodic cues. Our study determined discrimination of speech sounds in input mimicking natural speech variability, and detection of deviations in regular pitch relationships (rule violations) between speech sounds. We investigated the automaticity and the influence of attention and explicit awareness on these changes by recording the neurophysiological mismatch negativity (MMN) and P3a as well as task performance from 21 adults. The results showed neural discrimination of phonemes and rule violations as indicated by MMN and P3a, regardless of whether the sounds were attended or not, even when participants could not explicitly describe the rule. While small sample size precluded statistical analysis of some outcomes, we still found preliminary associations between the MMN amplitudes, task performance, and emerging explicit awareness of the rule. Our results highlight the automaticity of processing complex aspects of speech as a basis for the emerging conscious perception and explicit awareness of speech properties. While MMN operates at the implicit processing level, P3a appears to work at the borderline of implicit and explicit.
  • Hänninen, Timo S.; Verbitsky, Igor E. (2021)
  • Solala, Eelis; Losilla, Sergio A.; Sundholm, Dage; Xu, Wenhua; Parkkinen, Pauli (2017)
    We present an integration scheme for optimizing the orbitals in numerical electronic structure calculations on general molecules. The orbital optimization is performed by integrating the Helmholtz kernel in the double bubble and cube basis, where bubbles represent the steep part of the functions in the vicinity of the nuclei, whereas the remaining cube part is expanded on an equidistant threedimensional grid. The bubbles' part is treated by using one-center expansions of the Helmholtz kernel in spherical harmonics multiplied with modified spherical Bessel functions of the first and second kinds. The angular part of the bubble functions can be integrated analytically, whereas the radial part is integrated numerically. The cube part is integrated using a similar method as we previously implemented for numerically integrating two-electron potentials. The behavior of the integrand of the auxiliary dimension introduced by the integral transformation of the Helmholtz kernel has also been investigated. The correctness of the implementation has been checked by performing Hartree-Fock self-consistent-field calculations on H-2, H2O, and CO. The obtained energies are compared with reference values in the literature showing that an accuracy of 10(-4) to 10(-7) E-h can be obtained with our approach. Published by AIP Publishing.
  • Mutanen, Tuomas P.; Kukkonen, Matleena; Nieminen, Jaakko O.; Stenroos, Matti; Sarvas, Jukka; Ilmoniemi, Risto J. (2016)
    Combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) often suffers from large muscle artifacts. Muscle artifacts can be removed using signal-space projection (SSP), but this canmake the visual interpretation of the remaining EEG data difficult. We suggest to use an additional step after SSP that we call source-informed reconstruction (SIR). SSP-SIR improves substantially the signal quality of artifactual TMS-EEG data, causing minimal distortion in the neuronal signal components. In the SSP-SIR approach, we first project out the muscle artifact using SSP. Utilizing an anatomical model and the remaining signal, we estimate an equivalent source distribution in the brain. Finally, we map the obtained source estimate onto the original signal space, again using anatomical information. This approach restores the neuronal signals in the sensor space and interpolates EEG traces onto the completely rejected channels. The introduced algorithm efficiently suppresses TMS-related muscle artifacts in EEG while retaining well the neuronal EEG topographies and signals. With the presented method, we can remove muscle artifacts from TMS-EEG data and recover the underlying brain responses without compromising the readability of the signals of interest. (C) 2016 Elsevier Inc. All rights reserved.
  • Casas, Santiago; Karananas, Georgios K.; Pauly, Martin; Rubio, Javier (2019)
    We discuss the cosmological phenomenology of biscalar-tensor models displaying a maximally symmetric Einstein-frame kinetic sector and constructed on the basis of scale symmetry and volumepreserving diffeomorphisms. These theories contain a single dimensionful parameter Lambda(0) -associated with the invariance under the aforementioned restricted coordinate transformations-and a massless dilaton field. At large field values these scenarios lead to inflation with no generation of isocurvature perturbations. The corresponding predictions depend only on two dimensionless parameters, which characterize the curvature of the field manifold and the leading-order behavior of the inflationary potential. For Lambda(0) = 0 the scale symmetry is unbroken and the dilaton admits only derivative couplings to matter, evading all fifthforce constraints. For Lambda(0)( )not equal 0 the field acquires a runaway potential that can support a dark-energy - dominated era at late times. We confront a minimalistic realization of this appealing framework with observations using a Markov chain Monte Carlo approach, with likelihoods from present baryon acoustic oscillation, type la supernova, and cosmic microwave background data. A Bayesian model comparison indicates a preference for the considered model over ACDM, under certain assumptions for the priors. The impact of possible consistency relations among the early and late Universe dynamics that can appear within this setting is discussed with the use of correlation matrices. The results indicate that a precise determination of the inflationary observables and the dark energy equation of state could significantly constrain the model parameters.
  • Hautasaari, Pekka; Savic, Andrej M.; Loberg, Otto; Niskanen, Eini; Kaprio, Jaakko; Kujala, Urho M.; Tarkka, Ina M. (2017)
    Associations between long-term physical activity and cortical function and brain structure are poorly known. Our aim was to assess whether brain functional and/or structural modulation associated with long-term physical activity is detectable using a discordant monozygotic male twin pair design. Nine monozygotic male twin pairs were carefully selected for an intrapair difference in their leisure-time physical activity of at least three years duration (mean age 34 +/- 1 years). We registered somatosensory mismatch response (SMMR) in EEG to electrical stimulation of fingers and whole brain MR images. We obtained exercise history and measured physical fitness and body composition. Equivalent electrical dipole sources of SMMR as well as gray matter (GM) voxel counts in regions of interest indicated by source analysis were evaluated. SMMR dipolar source strengths differed between active and inactive twins within twin pairs in postcentral gyrus, medial frontal gyrus and superior temporal gyrus and in anterior cingulate (AC) GM voxel counts differed similarly. Compared to active twins, their inactive twin brothers showed greater dipole strengths in short periods of the deviant-elicited SMMR and larger AC GM voxel counts. Stronger activation in early unattended cortical processing of the deviant sensory signals in inactive co-twins may imply less effective gating of somatosensory information in inactive twins compared to their active brothers. Present findings indicate that already in 30's long-term physical activity pattern is linked with specific brain indices, both in functional and structural domains.
  • Salmela, Viljami; Salo, Emma; Salmi, Juha; Alho, Kimmo (2018)
    The fronto-parietal attention networks have been extensively studied with functional magnetic resonance imaging (fMRI), but spatiotemporal dynamics of these networks are not well understood. We measured event-related potentials (ERPs) with electroencephalography (EEG) and collected fMRI data from identical experiments where participants performed visual and auditory discrimination tasks separately or simultaneously and with or without distractors. To overcome the low temporal resolution of fMRI, we used a novel ERP-based application of multivariate representational similarity analysis (RSA) to parse time-averaged fMRI pattern activity into distinct spatial maps that each corresponded, in representational structure, to a short temporal ERP segment. Discriminant analysis of ERP-fMRI correlations revealed 8 cortical networks-2 sensory, 3 attention, and 3 other-segregated by 4 orthogonal, temporally multifaceted and spatially distributed functions. We interpret these functions as 4 spatiotemporal components of attention: modality-dependent and stimulus-driven orienting, top-down control, mode transition, and response preparation, selection and execution.