Does the Simon Effect Interfere with the Synergy Between Perception and Action?

Research suggests that – particularly – the execution of precision-demanding far-aiming tasks necessitates an optimal coupling between perception and action. In this regard, the duration of the last fixation before initiating movement – i.e., the Quiet Eye (QE) – has been functionally related to subsequent motor performance. In the current study, we investigated potential mechanisms of QE by applying the Simon paradigm – i.e., cognitive interferences evoked by stimulus-effect incompatibilities over response selection. To this end, we had participants throw balls as precisely as possible, either with their left or right hand (hands condition, HC) or at left or right targets (targets condition, TC), respectively. Via monaural auditory stimuli, participants received information about the hand side and the target side, respectively, either with compatible (i.e., congruent stimulus-effect side) or incompatible (i.e., incongruent stimulus-effect side) stimulus-effect mappings. Results showed that participants reacted slower and showed later first fixation onsets at the target in incompatible vs. compatible trials, thus, replicating and extending the classical Simon effect. Crucially, in the HC, there were earlier QE onsets and longer QE durations in incompatible (vs. compatible) trials, suggesting an inhibition of cognitive interferences over response selection to preserve motor performance. These findings are in line with attentional explanations of QE, suggesting optimized attentional control with efficient management of limited cognitive resources (optimal-attentional-control explanation) or with the inhibition of alternative response parametrization (inhibition explanation).

Assessment of the Dynamics of Temperature Changes in the Knee Joint Area in Response to Selected Cooling Agents in Thermographic Tests

Although local cryotherapy (LC) is performed with various cooling agents (CAg) such as ice, water, and gasses, in clinical practice, it is mostly performed with cooling gasses. Presently, LC with cooling gasses is very popular but the inference about the thermal (stimulus) effect on the tissues is mainly based on research carried out using ice packs. The proposed objective of the study was to evaluate the dynamics of temperature changes in the knee joint area in response to a 3-min exposure to liquid nitrogen vapors (LNVs), cold air (CA) and ice bag (IB). The study group included 23 healthy volunteers with an average age of 26.67 ± 4.56. The exposed (ROIE) and contralateral (ROINE) areas of the knee joint after exposure to CAg were observed. Immediately after 3 min of LC, the ROIE temperature dropped by 10.11 ± 0.91 °C after LNV, 7.59 ± 0.14 °C after IB and 6.76 ± 1.3 °C after CA. Significant tissue cooling was maintained up to 15 min after LNV (p < 0.01), 10 min after IB (p < 0.05) and 5 min after CA (p < 0.05). LC causes significant temperature changes both in ROIE and ROINE. The greatest cooling potential was demonstrated for LNV and the lowest for CA.

Concurrent Validity of Inertially Sensed Measures during Voluntary Body Sway in Silence and while Exposed to a Rhythmic Acoustic Stimulus: A Pilot Study

<b><i>Introduction:</i></b> The effect of rhythmic acoustic stimuli on body sway is of increasing interest due to their positive contribution when training or restoring the control of movement. Inertial sensors show promise as a portable, easier, and more affordable method compared to the force plate “gold standard” concerning the evaluation of postural sway. This study examined the concurrent validity of inertially sensed measures of voluntary body sway against those obtained with a force plate, in silence and while exposed to a rhythmic acoustic stimulus. <b><i>Methods:</i></b> Temporal (sway duration and variability) and spatial (trajectory length, variability, range, velocity, and area) body sway variables were extracted using an inertial sensor (at L5) in synchronization with a force plate, during anteroposterior body sway in silence and while exposed to a rhythmic acoustic stimulus (<i>n</i> = 18 young women; two 70-s trials in each condition). Statistics included bivariate correlations between the inertially sensed and the force plate measures, separately, in silence and with a rhythmic acoustic stimulus, as well as for the effect of the rhythmic acoustic stimulus (percentage difference from silence) (<i>p</i> ≤ 0.05, SPSS v25.0). <b><i>Results:</i></b> The inertially sensed measures demonstrated good-to-excellent concurrent validity for all temporal and almost all spatial variables, both in silence and with rhythmic acoustic stimulus (<i>r</i> &#x3e; 0.75, <i>p</i> = 0.000), as well as for the rhythmic acoustic-stimulus effect (<i>r</i> &#x3e; 0.75, <i>p</i> ≤ 0.05). <b><i>Conclusion:</i></b> The inertially sensed measures of the voluntary anteroposterior body sway demonstrated an overall good-to-excellent concurrent validity against those obtained with the force plate “gold standard,” both in the silence and the rhythmic acoustic stimulus conditions, as well as for the rhythmic acoustic-stimulus effect. The findings of this pilot study allow the recommendation of inertial sensing for the evaluation of postural control alterations when exposed to rhythmic acoustic stimuli, a condition of increasing interest due to the positive contribution of such stimuli when training or restoring the control of movement.

Foreign accent

Mandarin speakers’ productions of English sentences, spontaneous speech, and filtered speech were rated for degree of foreign accent by native English and Mandarin listeners. Results showed Mandarin speakers with 12 years' length of residence (LOR) in the U.S. were rated to be accented as those with zero LOR. Untrained native Mandarin listeners with no LOR in the target language environment were comparable to native English listeners in gauging degree of foreign accent based on sentences and spontaneous speech. No stimulus effect was found between sentences and spontaneous speech for accent rating. Filtered natural speech appeared to attenuate degree of foreign accent and Mandarin listeners were not able to assess foreign accent based on long excerpts of filtered speech. The findings suggest that LOR is not an important predictor of degree of foreign accent for adult speakers with late age of arrival (AOA).

The phase of Theta oscillations modulates successful memory formation at encoding

Several past studies have shown that attention and perception can depend upon the phase of ongoing neural oscillations at stimulus onset. Here, we extend this idea to the memory domain. We tested the hypothesis that ongoing fluctuations in neural activity have an impact on memory encoding using a picture paired-associates task to gauge episodic memory performance. Experiment 1 capitalized on the principle of phase reset. We tested if subsequent memory performance fluctuates rhythmically, time-locked to a reset cue presented before the to-be-remembered pairs. We found indication that behavioral performance was periodically and selectively modulated at theta frequency (∼4 Hz). In Experiment 2 we focused on prestimulus ongoing activity using scalp EEG recorded while participants performed the pair-associate task. We analyzed subsequent memory performance as a function of theta and alpha activity around the presentation of the to-be-remembered pairs. The results of the pre-registered analyses, using large electrode clusters and generic spectral ranges, returned null results of prestimulus phase-behavior correlation. However, we found that post-stimulus theta-power modulations in left frontal scalp predicted subsequent memory performance. This post-stimulus effect in theta power was used to guide a post-hoc prestimulus phase analysis, narrowed down to more precise scalp location and frequency. This analysis returned a correlation between prestimulus theta phase and subsequent memory. Altogether, these results suggest that the prestimulus theta activity at encoding has an impact on later memory performance.

Stimulus–effect relations for left ventricular growth obtained with a simple multi-scale model: the influence of hemodynamic feedback

Cardiac growth is an important mechanism for the human body to respond to changes in blood flow demand. Being able to predict the development of chronic growth is clinically relevant, but so far models to predict growth have not reached consensus on the stimulus–effect relation. In a previously published study, we modeled cardiac and hemodynamic function through a lumped parameter approach. We evaluated cardiac growth in response to valve disease using various stimulus–effect relations and observed an unphysiological decline pump function. Here we extend that model with a model of hemodynamic feedback that maintains mean arterial pressure and cardiac output through adaptation of peripheral resistance and circulatory unstressed volume. With the combined model, we obtain stable growth and restoration of pump function for most growth laws. We conclude that a mixed combination of stress and strain stimuli to drive cardiac growth is most promising since it (1) reproduces clinical observations on cardiac growth well, (2) requires only a small, clinically realistic adaptation of the properties of the circulatory system and (3) is robust in the sense that results were fairly insensitive to the exact choice of the chosen mechanics loading measure. This finding may be used to guide the choice of growth laws in more complex finite element models of cardiac growth, suitable for predicting the response to spatially varying changes in tissue load. Eventually, the current model may form a basis for a tool to predict patient-specific growth in response to spatially homogeneous changes in tissue load, since it is computationally inexpensive.

Stat3-mTOR signaling mediates the stimulation of GLP-1 production induced by IL-27

GLP-1 is a potent glucose-dependent insulinotropic hormone derived from intestinal L cells. Inflammatory Interleukin-27 (IL-27), a pleiotropic two-chain cytokine, is composed of EBI3 and IL-27 p28 subunits. IL-27 has a protective effect on pancreatic β-cell function. The relationship between IL-27 and GLP-1 is still unexplored. Here we showed interleukin-27-stimulated GLP-1 production via the Stat3-mTOR-dependent mechanism. Interleukin 27 receptor subunit alpha (IL-27 Rα) was detected in ileum and STC-1 cells. Co-localization of EBI3 and GLP-1 was observed not only in mouse ileums but also in human ileums and colons. Third-ventricular infusion of IL-27 increased ileal and plasma GLP-1 in both lean C57BL/6J mice and diet-induced obese and diabetic mice. These changes were associated with a significant increase in Stat3-mTOR activity. Treatment of STC-1 cells with IL-27 contributed to the increments of Stat3-mTOR signaling and GLP-1. Interference of mTOR activity by mTOR siRNA or rapamycin abolished the stimulation of GLP-1 production induced by IL-27 in STC-1 cells. Stat3 siRNA also blocked the stimulus effect of IL-27 on GLP-1. IL-27 increased the interaction of mTOR and Stat3 in STC-1 cells. Our results identify Stat3-mTOR as a critical signaling pathway for the stimulation of GLP-1 induced by IL-27.