Search results for " Stimulus"
showing 10 items of 75 documents
Mismatch brain response to speech sound changes in rats
2011
Understanding speech is based on neural representations of individual speech sounds. In humans, such representations are capable of supporting an automatic and memory-based mechanism for auditory change detection, as reflected by the mismatch negativity of event-related potentials. There are also findings of neural representations of speech sounds in animals, but it is not known whether these representations can support the change detection mechanism analogous to that underlying the mismatch negativity in humans. To this end, we presented synthesized spoken syllables to urethane-anesthetized rats while local field potentials were epidurally recorded above their primary auditory cortex. In a…
Media Effects: Cumulation and Duration
2017
The cumulation of media effects describes a process during which numerous (often, but not necessarily, small) effects accumulate over time as individuals use a certain medium or specific media contents repeatedly. Cumulative effects are especially central in forming individuals' perceptions of reality and are therefore a central premise in several theories and approaches that explain media effects (e.g., cultivation, agenda-setting, or spiral of silence). Whereas effects of single stimuli typically persist only in the short term, cumulative effects of media messages are long-term effects. This entry theorizes on the processes occurring between the short-term effects of a single stimulus and…
Modulation of cortical motor outputs by the symbolic meaning of visual stimuli
2010
The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is preceded b…
Visual mismatch negativity (vMMN): a prediction error signal in the visual modality
2015
Frontiers in Human Neuroscience, 8
Basic processes in interference paradigms
2021
The aim of the present thesis is to investigate the source of Stroop (interference) effects in weak bilinguals (Experiment 1) and in early language learning (Experiment 2-6). Participants performed a bilingual colour-word Stroop task with intermixed first language (L1) and second language (L2) words. The typical finding from the Stroop literature is slower and less accurate responding when the word and colour are incongruent (e.g., “red” in blue) relative to congruent (e.g., “red” in red). Interestingly, this congruency effect occurs for the colour words from both L1 and L2. What produces this congruency effect? That is, what is the source of the conflict produced by incongruent colour word…
Reproducibility of Rolandic beta rhythm modulation in MEG and EEG
2022
The Rolandic beta rhythm, at ∼20 Hz, is generated in the somatosensory and motor cortices and is modulated by motor activity and sensory stimuli, causing a short lasting suppression that is followed by a rebound of the beta rhythm. The rebound reflects inhibitory changes in the primary sensorimotor (SMI) cortex, and thus it has been used as a biomarker to follow the recovery of patients with acute stroke. The longitudinal stability of beta rhythm modulation is a prerequisite for its use in long-term follow-ups. We quantified the reproducibility of beta rhythm modulation in healthy subjects in a 1-year-longitudinal study both for MEG and EEG at T0, 1 month (T1-month, n = 8) and 1 year (T1-ye…
HOW DO FISCAL CONSOLIDATION AND FISCAL STIMULI IMPACT ON THE SYNCHRONIZATION OF BUSINESS CYCLES?
2017
Using quarterly data for a panel of advanced economies, we show that synchronized fiscal consolidation (stimulus) programmes in different countries make their business cycles more closely linked. We also find: (i) some evidence of decoupling when an inflation targeting regime is unilaterally adopted; (ii) an increase in business cycle synchronization when countries fix their exchange rates and become members of a monetary union; (iii) a positive effect of bilateral trade on the synchronization of business cycles. Global factors, such as a rise in global risk aversion and uncertainty and a reversal of nonstandard expansionary monetary policy, can also reduce the degree of co-movement of busi…
Gating Patterns to Proprioceptive Stimulation in Various Cortical Areas : An MEG Study in Children and Adults using Spatial ICA
2020
Proprioceptive paired-stimulus paradigm was used for 30 children (10–17 years) and 21 adult (25–45 years) volunteers in magnetoencephalography (MEG). Their right index finger was moved twice with 500-ms interval every 4 ± 25 s (repeated 100 times) using a pneumatic-movement actuator. Spatial-independent component analysis (ICA) was applied to identify stimulus-related components from MEG cortical responses. Clustering was used to identify spatiotemporally consistent components across subjects. We found a consistent primary response in the primary somatosensory (SI) cortex with similar gating ratios of 0.72 and 0.69 for the children and adults, respectively. Secondary responses with similar …
Is lack of habituation a biomarker of migraine? A critical perspective
2015
Processing of sensory stimuli has been supposed to be dysfunctioning in migraine. A basis for such abnormality has been identified in a defective ability to habituate to repetitive sensorial stimulation. Habituation, i.e. the way the nervous system attenuates response to repeated non noxious stimuli is a fundamental function of sensory systems, that allows appropriate adaptation of neural responses to the relevance of incoming stimuli. In humans, habituation can be studied by evoked potentials where it is indexed by a reduction of amplitude of the evoked response to repeated stimulation. After the first evidence by Schoenen et al in 1995[1] of reduced habituation to visual evoked potentials…
Analgesic and physiological effects in conscious sedation with different nitrous oxide concentrations
2015
Objectives: to study the physiological changes, as well as the psychosedative and analgesic effects of nitrous oxide, in experimental conditions. Study Design: 101 dental students volunteers participated in a single nitrous oxide sedation session without dental treatment. Signs and symptoms were registered during and after the procedure. Pulse rate and hemoglobin oxygen saturation were monitored at: 100 per cent O 2 , 30 per cent N 2 O, 50 per cent N 2 O and 5 minutes after 100 per cent O 2 . A Likert scale was used to evaluate pain perception. The analgesic effects of nitrous oxide were evaluated at: 30 per cent N 2 O, 50 per cent N 2 O, and five minutes postoperatively. Results: Pulse rat…