Search results for "speech recognition"
showing 10 items of 357 documents
Individual Independent Component Analysis on EEG: Event-Related Responses Vs. Difference Wave of Deviant and Standard Responses
2016
Independent component analysis (ICA) is often used to spatially filter event-related potentials (ERPs). When an oddball paradigm is applied to elicit ERPs, difference wave (DW, responses of deviant stimuli minus those of standard ones) is often used to remove the common responses between the deviant and the standard. Thus, DW can be produced first, and then ICA is used to decompose the DW. Or, ICA is performed on responses of the deviant and standard stimuli separately, and then DW is applied on the filtered responses. In this study, we compared the two approaches to analyzing mismatch negativity (MMN). We found that DW introduced noise in the time and space domains, resulting in more diffi…
Extract Mismatch Negativity and P3a through Two-Dimensional Nonnegative Decomposition on Time-Frequency Represented Event-Related Potentials
2010
This study compares the row-wise unfolding nonnegative tensor factorization (NTF) and the standard nonnegative matrix factorization (NMF) in extracting time-frequency represented event-related potentials—mismatch negativity (MMN) and P3a from EEG under the two-dimensional decomposition The criterion to judge performance of NMF and NTF is based on psychology knowledge of MMN and P3a MMN is elicited by an oddball paradigm and may be proportionally modulated by the attention So, participants are usually instructed to ignore the stimuli However the deviant stimulus inevitably attracts some attention of the participant towards the stimuli Thus, P3a often follows MMN As a result, if P3a was large…
Cardiorespiratory Coordination after Training and Detraining. A Principal Component Analysis Approach
2016
Our purpose was to study the effects of different training modalities and detraining on cardiorespiratory coordination (CRC). Thirty-two young males were randomly assigned to four training groups: aerobic (AT), resistance (RT), aerobic plus resistance (AT + RT), and control (C). They were assessed before training, after training (6 weeks) and after detraining (3 weeks) by means of a graded maximal test. A principal component (PC) analysis of selected cardiovascular and cardiorespiratory variables was performed to evaluate CRC. The first PC (PC1) coefficient of congruence in the three conditions (before training, after training and after detraining) was compared between groups. Two PCs were …
Independent component analysis on the mismatch negativity in an uninterrupted sound paradigm.
2008
We compared the efficiency of the independent component analysis (ICA) decomposition procedure against the difference wave (DW) and optimal digital filtering (ODF) procedures in the analysis of the mismatch negativity (MMN). The comparison was made in a group of 54 children aged 8-16 years. The MMN was elicited in a passive oddball protocol presenting uninterrupted auditory stimulation consisting of two frequent alternating tones (600 and 800 Hz) of 100 ms duration each. Infrequently, one of the 600 Hz tones was shortened to 50 or 30 ms. The event related potentials (ERPs) were decomposed into the MMN-like and non-MMN-like independent components (ICs) through the FastICA algorithm. The ICA …
Music Training Enhances Rapid Neural Plasticity of N1 and P2 Source Activation for Unattended Sounds
2012
Neurocognitive studies have demonstrated that long-term music training enhances the processing of unattended sounds. It is not clear, however, whether music training also modulates rapid (within tens of minutes) neural plasticity for sound encoding. To study this phenomenon, we examined whether adult musicians display enhanced rapid neural plasticity compared to non-musicians. More specifically, we compared the modulation of P1, N1, and P2 responses to standard sounds between four unattended passive blocks. Among the standard sounds, infrequently presented deviant sounds were presented (the so-called oddball paradigm). In the middle of the experiment (after two blocks), an active task was p…
Information domain approach to the investigation of cardio-vascular, cardio-pulmonary, and vasculo-pulmonary causal couplings
2011
The physiological mechanisms related to cardio-vascular (CV), cardio-pulmonary (CP), and vasculo-pulmonary (VP) regulation may be probed through multivariate time series analysis tools. This study applied an information domain approach for the evaluation of non-linear causality to the beat-to-beat variability series of heart period (t), systolic arterial pressure (s), and respiration (r) measured during tilt testing and paced breathing (PB) protocols. The approach quantifies the causal coupling from the series i to the series j (C(ij)) as the amount of information flowing from i to j. A measure of directionality is also obtained as the difference between two reciprocal causal couplings (D(i…
Roentgenological observations on vocal fold length-changes with special reference to register transition and open/covered voice
1992
This paper examines the length-changes of the vocal folds as a function of voice pitch. Changes in normalized vocal fold elongation (strain) were measured indirectly from calcification points in several laryngeal structures from roentgenological exposures during singing. Changes in vocal fold strain are shown to occur mainly in the register transition area, i.e. the area within which all register changes take place. Changes in vocal fold strain appeared similar in male and female subjects. Evidence for different strain patterns in covered and open singing is presented for female subjects: Strain is higher in non-singers and (“incorrect”) open voice, lower in singers and (“correct”) covered …
Priming in word stem completion tasks: comparison with previous results in word fragment completion tasks
2015
This study investigates priming in an implicit Word Stem Completion (WSC) task. A total of 305 participants performed a WSC task in two phases (study and test). The test phase included 63 unique-solution stems and 63 multiple-solution stems. After confirming the presence of priming (mean = 0.22), analysis revealed that it was stronger in the case of multiple-solution stems, indicating that the stems were not a homogeneous group of stimuli. Thus, further analyses were performed only for the data of the unique-solution stems. The correlations between priming and a set of conceptual (familiarity, frequency of use, number of meanings) and non-conceptual (letters/blanks ratio and difficulty of c…
The nature of the syllabic neighbourhood effect in French
2006
International audience; We investigated whether and how sublexical units such as phonological syllables mediate access to the lexicon in French visual word recognition. To do so, two lexical decision task (LDT) experiments examined the nature of the syllabic neighbourhood effect. In Experiments 1a and b, the number of higher frequency syllabic neighbours was manipulated while controlling for the first bigram. The results failed to show a pure syllabic neighbourhood effect. In Experiments 2a and b, syllabic neighbourhood and bigram frequency were factorially manipulated. The interaction showed that the syllabic neighbourhood effect was inhibitory when bigram frequency was high, whereas it wa…
Effect of Enculturation on the Semantic and Acoustic Correlates of Polyphonic Timbre
2011
polyphonic timbre perception was investigated in a cross-cultural context wherein Indian and Western nonmusicians rated short Indian and Western popular music excerpts (1.5 s, n = 200) on eight bipolar scales. Intrinsic dimensionality estimation revealed a higher number of perceptual dimensions in the timbre space for music from one's own culture. Factor analyses of Indian and Western participants' ratings resulted in highly similar factor solutions. The acoustic features that predicted the perceptual dimensions were similar across the two participant groups. Furthermore, both the perceptual dimensions and their acoustic correlates matched closely with the results of a previous study perfor…