511 research outputs found
Predictability modulates the affective and sensory-discriminative neural processing of pain
Knowing what is going to happen next, that is, the capacity to predict upcoming events, modulates the extent to which aversive stimuli induce stress and anxiety. We explored this issue by manipulating the temporal predictability of aversive events by means of a visual cue, which was either correlated or uncorrelated with pain stimuli (electric shocks). Subjects reported lower levels of anxiety, negative valence and pain intensity when shocks were predictable. In addition to attenuate focus on danger, predictability allows for correct temporal estimation of, and selective attention to, the sensory input. With functional magnetic resonance imaging, we found that predictability was related to enhanced activity in relevant sensory-discriminative processing areas, such as the primary and secondary sensory cortex and posterior insula. In contrast, the unpredictable more aversive context was correlated to brain activity in the anterior insula and the orbitofrontal cortex, areas associated with affective pain processing. This context also prompted increased activity in the posterior parietal cortex and lateral prefrontal cortex that we attribute to enhanced alertness and sustained attention during unpredictability. (c) 2006 Elsevier Inc. All rights reserved.This study was supported by grants from The Swedish
Research Council (2003-5810), The family Hedlund Foundation
and Karolinska Institutet. The project was finished in the context of
Stockholm Brain Institute.info:eu-repo/semantics/publishedVersio
Disruption of order information by irrelevant items: A serial recognition paradigm
irrelevant speech effect (ISE) is defined as a decrement in visually presented digit-list short-term memory performance due to exposure to irrelevant auditory material. Perhaps the most successful theoretical explanation of the effect is the changing state hypothesis. This hypothesis explains the effect in terms of confusion between amodal serial order cues, and represents a view based on the interference caused by the processing of similar order information of the visual and auditory materials. An alternative view suggests that the interference occurs as a consequence of the similarity between the visual and auditory contents of the stimuli. An important argument for the former view is the observation that ISE is almost exclusively observed in tasks that require memory for serial order. However, most short-term memory tasks require that both item and order information be retained in memory. An ideal task to investigate the sensitivity of maintenance of serial order to irrelevant speech would be one that calls upon order information but not item information. One task that is particularly suited to address this issue is serial recognition. In a typical serial recognition task, a list of items is presented and then probed by the same list in which the order of two adjacent items has been transposed. Due to the re-presentation of the encoding string, serial recognition requires primarily the serial order to be maintained while the content of the presented items is deemphasized. In demonstrating a highly significant ISE of changing versus steady-state auditory items in a serial recognition task, the present finding lends support for and extends previous empirical findings suggesting that irrelevant speech has the potential to interfere with the coding of the order of the items to be memorized. (c) 2006 Elsevier B.V. All rights reserved
Interaction between a verbal working memory network and the medial temporal lobe
The irrelevant speech effect illustrates that sounds that are irrelevant to a visually presented short-term memory task still interfere with neuronal function. In the present study we explore the functional and effective connectivity of such interference. The functional connectivity analysis suggested an interaction between the level of irrelevant speech and the correlation between in particular the left superior temporal region, associated with verbal working memory, and the left medial temporal lobe. Based on this psycho-physiological interaction, and to broaden the understanding of this result, we performed a network analysis, using a simple network model for verbal working memory, to analyze its interaction with the medial temporal lobe memory system. The results showed dissociations in terms of network interactions between frontal as well as parietal and temporal areas in relation to the medial temporal lobe. The results of the present study suggest that a transition from phonological loop processing towards an engagement of episodic processing might take place during the processing of interfering irrelevant sounds. We speculate that, in response to the irrelevant sounds, this reflects a dynamic shift in processing as suggested by a closer interaction between a verbal working memory system and the medial temporal lobe memory system. (c) 2006 Elsevier Inc. All rights reserved.info:eu-repo/semantics/publishedVersio
Broca's region: A causal role in implicit processing of grammars with crossed non-adjacent dependencies
Non-adjacent dependencies are challenging for the language learning machinery and are acquired later than adjacent dependencies. In this transcranial magnetic stimulation (TMS) study, we show that participants successfully discriminated between grammatical and non-grammatical sequences after having implicitly acquired an artificial language with crossed non-adjacent dependencies. Subsequent to transcranial magnetic stimulation of Broca's region, discrimination was impaired compared to when a language-irrelevant control region (vertex) was stimulated. These results support the view that Broca's region is engaged in structured sequence processing and extend previous functional neuroimaging results on artificial grammar learning (AGL) in two directions: first, the results establish that Broca's region is a causal component in the processing of non-adjacent dependencies, and second, they show that implicit processing of non-adjacent dependencies engages Broca's region. Since patients with lesions in Broca's region do not always show grammatical processing difficulties, the result that Broca's region is causally linked to processing of non-adjacent dependencies is a step towards clarification of the exact nature of syntactic deficits caused by lesions or perturbation to Broca's region. Our findings are consistent with previous results and support a role for Broca's region in general structured sequence processing, rather than a specific role for the processing of hierarchically organized sentence structure. (C) 2017 Published by Elsevier B.V.Max Planck Institute for PsycholinguisticsDonders Institute for BrainCognition and BehaviourCentre for Cognitive NeuroimagingRadboud University NijmegenFundacao para a Ciencia e Tecnologia [PTDC/PSI-PC0/110734/2009]IBB/CBME, LA [PEst-OE/EQB/LA0023/2013]Vetenskapsradet [8276]Swedish Dyslexia FoundationFEDER/POC
Toxicological evaluation of complex mixtures by pattern recognition: Correlating chemical fingerprints to mutagenicity
We describe the use of pattern recognition and multivariate regression in the assessment of complex mixtures by correlating chemical fingerprints to the mutagenicity of the mixtures. Mixtures were 20 organic extracts of exhaust particles, each containing 102-170 individual compounds such as polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, oxy-PAHs, and saturated hydrocarbons. Mixtures were characterized by full-scan GC-MS (gas chromatography-mass spectrometry). Data were resolved into peaks and spectra for individual compounds by an automated curve resolution procedure. Resolved chromatograms were integrated, resulting in a predictor matrix that was used as input to a principal component analysis to evaluate similarities between mixtures (i.e., classification). Furthermore, partial least-squares projections to latent structures were used to correlate the GC-MS data to mutagenicity, as measured in the Ames Salmonella assay (i.e., calibration). The best model (high r2 and Q2) identifies the variables that co-vary with the observed mutagenicity. These variables may subsequently be identified in more detail. Furthermore, the regression model can be used to predict mutagenicity from GC-MS chromatograms of other organic extracts. We emphasize that both chemical fingerprints as well as detailed data on composition can be used in pattern recognition.publishedVersio
The impact of reading and writing skills on a visual-motor integration task: a comparison between illiterate and literate subjects
Previous studies have shown a significant association between reading skills and the performance on visuo-motor
tasks. In order to clarify whether reading and writing skills modulate non-linguistic domains, we investigated the
performance of two literacy groups on a visuo-motor integration task with non-linguistic stimuli. Twenty-one
illiterate participants and twenty matched literate controls were included in the experiment. Subjects were instructed
to use the right or the left index finger to point to and touch a randomly presented target on the right or left side of a
touch screen. The results showed that the literate subjects were significantly faster in detecting and touching targets
on the left compared to the right side of the screen. In contrast, the presentation side did not affect the performance
of the illiterate group. These results lend support to the idea that having acquired reading and writing skills, and
thus a preferred left-to-right reading direction, influences visual scanning
Low Sense of Coherence (SOC) is a mirror of general anxiety and persistent depressive symptoms in adolescent girls - a cross-sectional study of a clinical and a non-clinical cohort
<p>Abstract</p> <p>Background</p> <p>The Sense of Coherence (SOC) scale is assumed to measure a distinct salutogenic construct separated from measures of anxiety and depression. Our aim was to challenge this concept.</p> <p>Methods</p> <p>The SOC-scale, Beck's Depression Inventory (BDI), Beck's Anxiety Inventory (BAI) , the emotional subscale of the Strengths and Difficulties Questionnaire (SDQ-em) and self-assessed health-related and physiological parameters were collected from a sample of non-clinical adolescent females (n = 66, mean age 16.5 years with a range of 15.9-17.7 years) and from female psychiatric patients (n = 73), mean age 16.8 years with a range of 14.5-18.4 years), with diagnoses of major depressive disorders (MDD) and anxiety disorders.</p> <p>Results</p> <p>The SOC scores showed high inverse correlations to BDI, BAI and SDQ-em. In the non-clinical sample the correlation coefficient was -0.86 to -0.73 and in the clinical samples -0.74 to -0.53 (p < 0.001). Multiple regression models showed that BDI was the strongest predictor of SOC in the non-clinical (beta coefficient -0.47) and clinical sample (beta coefficient -0.52). The total degree of explanation of self assessed anxiety and depression on the SOC variance estimated by multiple R<sup>2 </sup>= 0.74, adjusted R<sup>2 </sup>= 0.73 in the non-clinical sample and multiple R<sup>2 </sup>= 0.66, adjusted R<sup>2 </sup>= 0.65 in the clinical sample.</p> <p>Multivariate analyses failed to isolate SOC as a separate construct and the SOC-scale, BDI, BAI and SDQ-em showed similar patterns of correlations to self-reported and physiological health parameters in both samples. The SOC-scale was the most stable measure over six months.</p> <p>Conclusions</p> <p>The SOC-scale did not appear to be a measure of a distinct salutogenic construct, but an inverse measure of persistent depressive symptoms and generalized social anxiety similar to the diagnostic criteria for major depressive disorder (MDD), dysthymic disorder, generalized anxiety disorder (GAD) or generalized social anxiety disorder (SAD) according to DSM-IV. These symptoms were better captured with SOC than by the specialized scales for anxiety and depression. Self-assessment scales that adequately identify MDD, dysthymic disorder, GAD and SAD need to be implemented. Comorbidity of these disorders is common in adolescent females and corresponds to a more severe symptomatology and impaired global function.</p
Detection of interictal epileptiform discharges: A comparison of on-scalp MEG and conventional MEG measurements
Objective: Conventional MEG provides an unsurpassed ability to, non-invasively, detect epileptic activity. However, highly resolved information on small neuronal populations required in epilepsy diagnostics is lost and can be detected only intracranially. Next-generation on-scalp magnetencephalography (MEG) sensors aim to retrieve information unavailable to conventional non-invasive brain imaging techniques. To evaluate the benefits of on-scalp MEG in epilepsy, we performed the first-ever such measurement on an epilepsy patient. Methods: Conducted as a benchmarking study focusing on interictal epileptiform discharge (IED) detectability, an on-scalp high-temperature superconducting quantum interference device magnetometer (high-Tc SQUID) system was compared to a conventional, low-temperature SQUID system. Coregistration of electroencephalopraphy (EEG) was performed. A novel machine learning-based IED-detection algorithm was developed to aid identification of on-scalp MEG unique IEDs. Results: Conventional MEG contained 24 IEDs. On-scalp MEG revealed 47 IEDs (16 co-registered by EEG, 31 unique to the on-scalp MEG recording). Conclusion: Our results indicate that on-scalp MEG might capture IEDs not seen by other non-invasive modalities. Significance: On-scalp MEG has the potential of improving non-invasive epilepsy evaluation. (C) 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V
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