Auditory-Motor Rhythms and Speech Processing in French and German Listeners

Moving to a speech rhythm can enhance verbal processing in the listener by increasing temporal expectancies (Falk and Dalla Bella, 2016). Here we tested whether this hypothesis holds for prosodically diverse languages such as German (a lexical stress-language) and French (a non-stress language). Moreover, we examined the relation between motor performance and the benefits for verbal processing as a function of language. Sixty-four participants, 32 German and 32 French native speakers detected subtle word changes in accented positions in metrically structured sentences to which they previously tapped with their index finger. Before each sentence, they were cued by a metronome to tap either congruently (i.e., to accented syllables) or incongruently (i.e., to non-accented parts) to the following speech stimulus. Both French and German speakers detected words better when cued to tap congruently compared to incongruent tapping. Detection performance was predicted by participants' motor performance in the non-verbal cueing phase. Moreover, tapping rate while participants tapped to speech predicted detection differently for the two language groups, in particular in the incongruent tapping condition. We discuss our findings in light of the rhythmic differences of both languages and with respect to recent theories of expectancy-driven and multisensory speech processing

The effect of cognitive training on subsequent sleep characteristics

Introduction: Several studies have consistently shown that pre-sleep learning produces changes in sleep structure. Whereas the majority of these studies has mainly focused on post-training changes in sleep states (namely REM and NREM sleep amount) and, more recently, in specific electrophysiological features (e.g., sleep spindles, slow wave activity), very little attention has been paid to the hypothesis that pre-sleep learning might improve sleep quality, as expressed by sleep continuity, stability and cyclic organization measures. Furthermore, studies addressing the relationship between sleep and learning usually employ purely declarative or procedural tasks, neglecting that everyday life learning processes depend on the simultaneous activation of different memory systems. Recently, we have reported that a complex ecological learning task (requiring the simultaneous activation of several cognitive functions), intensively administered at bedtime, improves daytime sleep continuity and stability, possibly as a result of ongoing memory processes. To follow up our previous study, here we aimed to extend these findings to a night paradigm and to test whether a similar post-training sleep improvement may be obtained in a sample of individuals with sleep complaints. Specifically, our focus was on post-training changes in objective and subjective sleep quality. Furthermore, we compared overnight performance changes with those obtained over a wake retention period, in order to address the possible differential effect of sleep and wake on memory processes. Method: After a habituation night, twenty-one subjects (F=15, mean age: 27.5±7.7 years, all bad sleepers according to the Pittsburgh Sleep Quality Index) underwent conventional polygraphic recording under three conditions: 1) BL, baseline night sleep; 2) post-active control sleep (AC), a sleep episode preceded by a non-learning control task; 3) post-training sleep (TR), a sleep episode preceded by a complex ecological task. The same task as in TR was administered in a Wake condition (W), in which the retention period between training sessions corresponded to the duration of the subject’s baseline sleep time. Subjects underwent AC, TR and W conditions in balanced order. The complex cognitive task consisted in a slightly modified version of the famous word game “Ruzzle”. In this game, the player has two minutes to form as many words as possible and reach the highest score achievable with the 16 letters available in a 4x4 grid on an iPad screen. Performance measures were R-WORDS%, i.e., the number of detected words over total available words, and R-SCORE%, i.e., the global score achieved, depending on the number of words found, on their length and on the ability to use the coloured bonus letters which multiply letter or word values. Results: Post-training sleep (TR) showed a reduction in Stage 1 proportion (F=4.39, p=.021; TRTR and AC) and brief awakenings frequency (F=5.89, p=.007, BL>TR and AC), decreased frequency of arousals (F=6.25, p=.005; TRTR and AC) and functional uncertainty (FU) periods (F=14.23, pTR and AC), as well as a reduction of time spent in FU periods (F=515.33, pTR and AC); an increase in the number of NREM-REM cycles (F=4.51, p=.019; TR>BL and AC), and of time spent in cycles (F=4.77, p=.015; TR>BL and AC). This improvement in objective sleep quality was paralleled by that in subjective ratings, assessed through the Self-Rating Scale for Sleep and Awakenings Quality (χ2=9.13, p=.010; TRW), while the opposite effect emerged for the R-WORDS% (t=-2.96, p=.01; W>TR). Conclusions: Our results extend previous findings on post-training changes in sleep continuity, stability and organization to a sample of bad sleepers; also, they show that objective sleep improvement may be reflected in subjective sleep quality perception. Interestingly, the active control task also produced improvements in some of these features, prompting future investigations on the contribution to post-training sleep changes of additional factors not specifically linked to learning processes. As for performance, the finding of a significant sleep effect for the more complex performance measure (R-SCORE%) suggests that sleep preferentially promotes effective learning of elaborate cognitive strategies rather than that of simpler cognitive processes. In conclusion, in light of the importance of non-pharmacological treatments for sleep disturbances, this study offers the possibility to further explore planned cognitive training as a low-cost treatment strategy to improve sleep quality

Neural correlates of conscious visual processing

The objective of the current thesis is to evaluate the role of alpha band activity and neural trial-to-trial variability in conscious visual perception and their relationship to each other. We investigate these measures in electrophysiological recordings of monkeys as well as the electroencephalogram (EEG) of humans using a generalized flash suppression (GFS) paradigm.2021-06-0

Actively but not passively synchronized motor activity amplifies predictive timing

Previous studies have shown that the effect of temporal predictability of presented stimuli on attention allocation is enhanced by auditory-motor synchronization (AMS). The present P300 event-related potential study (N = 20) investigated whether this enhancement depends on the process of actively synchronizing one's motor output with the acoustic input or whether a passive state of auditory-motor synchrony elicits the same effect. Participants silently counted frequency deviants in sequences of pure tones either during a physically inactive control condition or while pedaling on a cycling ergometer. Tones were presented either at fixed or variable intervals. In addition to the pedaling conditions with fixed or variable stimulation, there was a third condition in which stimuli were adaptively presented in sync with the participants' spontaneous pedaling. We replicated the P300 enhancement for fixed versus variable stimulation and the amplification of this effect by AMS. Synchronization performance correlated positively with P300 amplitude in the fixed stimulation condition. Most interestingly, P300 amplitude was significantly reduced for the passive synchronization condition by adaptive stimulus presentation as compared to the fixed stimulation condition. For the first time we thus provide evidence that it is not the passive state of (even perfect) auditory-motor synchrony that facilitates attention allocation during AMS but rather the active process of synchronizing one's movements with external stimuli

Cortical mechanisms for tinnitus in humans /

PhD ThesisThis work sought to characterise neurochemical and neurophysiological processes underlying tinnitus in humans. The first study involved invasive brain recordings from a neurosurgical patient, along with experimental manipulation of his tinnitus, to map the cortical system underlying his tinnitus. Widespread tinnitus-linked changes in low- and high-frequency oscillations were observed, along with inter-regional and cross-frequency patterns of communication. The second and third studies compared tinnitus patients to controls matched for age, sex and hearing loss, measuring auditory cortex spontaneous oscillations (with magnetoencephalography) and neurochemical concentrations (with magnetic resonance spectroscopy) respectively. Unlike in previous studies not controlled for hearing loss, there were no group differences in oscillatory activity attributable to tinnitus. However, there was a significant correlation between gamma oscillations (>30Hz) and hearing loss in the tinnitus group, and between delta oscillations (1-4Hz) and perceived tinnitus loudness. In the neurochemical study, tinnitus patients had significantly reduced GABA concentrations compared to matched controls, and within this group there was a positive correlation between choline concentration (potentially linked to acetylcholine and/or neuronal plasticity) and both hearing loss, and subjective tinnitus intensity and distress. In light of present and previous findings, tinnitus may be best explained by a predictive coding model of perception, which was tested in the final experiment. This directly controlled the three main quantities comprising predictive coding models, and found that delta/theta/alpha oscillations (1-12Hz) encoded the precision of predictions, beta oscillations (12-30Hz) encoded changes to predictions, and gamma oscillations represented surprise (unexpectedness of stimuli based on predictions). The work concludes with a predictive coding model of tinnitus that builds upon the present findings and settles unresolved paradoxes in the literature. In this, precursor processes (in varying combinations) synergise to increase the precision associated with spontaneous activity in the auditory pathway to the point where it overrides higher predictions of ‘silence’.Medical Research Council Wellcome Trust and the National Institutes of Healt

Music evoked emotions are different-more often aesthetic than utilitarian

We disagree with Juslin & Västfjäll's (J&V's) thesis that music-evoked emotions are indistinguishable from other emotions in both their nature and underlying mechanisms and that music just induces some emotions more frequently than others. Empirical evidence suggests that frequency differences reflect the specific nature of music-evoked emotions: aesthetic and reactive rather than utilitarian and proactive. Additional mechanisms and determinants are suggested as predictors of emotions triggered by musi