Biology subjects

Lenoir, C.

Publications and source records attributed to Lenoir, C..

5 recordsLinked to original sources

bioRxiv2026

Beyond Onset Timing: Longer Sound Envelope Duration Enhances Neural Representation of the Musical Beat

Musical rhythm is often experienced with a periodic beat, serving as a temporal reference for coordination with the rhythm. Thus far, models of beat processing have mainly relied on representing sensory inputs as patterns of onset timing, with limited consideration of other sensory features. Here, we challenge this view by showing that the internal representation of beat is affected by other temporal features of the stimulus beyond onset timing alone. We recorded electroencephalography (EEG) while participants listened to rhythmic sequences designed to elicit a beat. Across conditions, we manipulated the duration of the tones conveying the rhythms, while keeping all other parameters identical, including overall intensity, speed, and rhythmic pattern structure. Crucially, the beat periodicity was enhanced in neural activity with increased sound duration, even though the beat periodicity was not prominent in the acoustic features, thus ruling out basic sensory confounds. These results demonstrate the preferential role of longer sound durations in fostering temporal scaffolding processes that integrate fast rhythmic inputs into behavior-relevant internal structures such as the beat. More generally, our findings are compatible with a holistic processing account whereby a range of features beyond onset timing may be integrated into a neural representation of rhythm. Graphical Abstract: Fig. 2EEG was recorded while listeners heard rhythmic sequences eliciting a beat. Sound duration (sonic duty cycle) was varied across four conditions while speed, pattern, and intensity stayed constant. Beat-related EEG responses increased with longer sounds, and were enhanced in all conditions compared to auditory nerve model envelopes, which did not show prominent energy at the beat periodicity, ruling out sensory confounds. Results support holistic rhythm processing beyond onset timing alone. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/721298v1_fig2.gif" ALT="Figure 2"> View larger version (27K): org.highwire.dtl.DTLVardef@10a0599org.highwire.dtl.DTLVardef@f5a95forg.highwire.dtl.DTLVardef@42d1ceorg.highwire.dtl.DTLVardef@dc58a7_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 2.C_FLOATNO EEG and auditory nerve model output analysis based on magnitude spectrum and autocorrelation. Each row represents a duty cycle condition. The two columns on the left represent the magnitude spectrum-based analysis. The first column represents the group-level averaged magnitude spectra at a pool of fronto-central electrodes, across conditions. Beat-related frequencies are shown in red, and beat-unrelated frequencies are shown in blue. Scalp topographies of the neural activity measured at the average magnitudes of beat-related (in red circle) and unrelated (in blue circle) frequencies are represented as insets. The second column represents the normalized magnitude spectra obtained from the auditory nerve model output for each duty cycle sequence. The two columns on the right represent the autocorrelation-based analysis (for visualization purposes, only a subset of lags from 0 to 2.4 s corresponding to the pattern duration is shown). The first column represents the group-level averaged autocorrelation function measured from the same pool of fronto-central electrodes, across conditions. Beat-related lags are shown in red, and beat-unrelated lags are shown in blue. The second column represents the autocorrelation function of the auditory nerve model output for each duty cycle sequence. C_FIG

neuroscience↗

bioRxiv2025

Interindividual variations in peak alpha frequency do not predict the magnitude or extent of secondary hyperalgesia induced by high-frequency stimulation

BackgroundPrevious studies have shown an association between interindividual variations in the frequency of alpha-band EEG oscillations such as estimates of peak alpha frequency (PAF) and pain sensitivity. Whether differences in PAF also influence the susceptibility to develop central sensitization (CS) is unknown. ObjectiveThis study aimed to determine if the PAF of vision- and sensorimotor-related alpha-band activity is associated with the magnitude and extent of secondary mechanical hyperalgesia induced by high-frequency stimulation (HFS) of the skin, a surrogate marker of CS. MethodsThe EEG was recorded in 32 healthy participants at rest during eyes open and eyes closed conditions, and during bilateral finger movements. Two methods were used to isolate vision- and sensorimotor-related alpha-band activity based on sensitivity to eye closure and movement: one based on an independent component analysis, the other on spectral subtraction. PAF was assessed using a center-of-gravity approach or the Fitting Oscillations and One-Over-F (FOOOF) method, accounting for the aperiodic EEG component. HFS was applied to the right forearm, and pinprick sensitivity was assessed at both forearms, before and 40 minutes after HFS. ResultsNeither sensorimotor-nor vision-related PAF were significantly correlated with the magnitude or extent of HFS-induced secondary hyperalgesia. Interestingly, at the non-sensitized forearm, participants with a higher vision-related PAF exhibited greater habituation to pinprick stimuli, suggesting that variations in PAF may relate to variations in sensory habituation. ConclusionInterindividual variations of PAF were not significantly associated with the susceptibility to develop HFS-induced secondary hyperalgesia. New and NoteworthyUsing several methods to estimate vision- and sensorimotor-related peak alpha frequency (PAF) in the EEG frequency spectrum, we found no significant association between interindividual variations in PAF and the susceptibility to develop secondary hyperalgesia following high-frequency stimulation (HFS) of the skin in healthy participants.

neuroscience↗

bioRxiv2024

Behavior-relevant periodized neural representation of acoustic but not tactile rhythm in humans

Music makes people move. This human propensity to coordinate movement with the rhythm of music requires multiscale temporal integration, allowing fast sensory events composing rhythmic input to be mapped onto slower internal templates such as periodic beats. Relatedly, beat perception has been shown to involve a selective enhancement of the beat periodicities in the neural response to rhythm. However, the extent to which this ability to move to the beat, and the related periodized neural representation, are shared across the senses beyond audition remains unknown. Here we addressed this question using acoustic and tactile rhythms, while recording separately the electroencephalography (EEG) responses and finger tapping to these rhythms in healthy volunteers. Consistent with previous studies, EEG responses to the acoustic rhythm featured significant enhancement of the beat, and this periodized neural representation was specifically concentrated within a low-frequency range below 15 Hz. In contrast, the same rhythm conveyed with tactile inputs elicited responses over a broader frequency range, up to 25Hz, with no significant periodization, and resulted in less stable tapping. Together, these findings indicate that low-frequency neural activity preferentially supports behavior-relevant internal representation of rhythmic input. However, this neural representation is not necessarily shared across the senses, as well as the ability to move to the beat, corroborating multimodal differences in beat perception. This low-frequency neural representation may thus reflect a process of multiscale temporal integration allowing the auditory system to go beyond mere tracking of onset timing and support higher-level internal representation and motor entrainment to rhythm. Significance statementIntegrating the fast sensory events composing music into slower temporal units is a cornerstone of beat perception and social interaction through music. The current study shows that this ability critically relies on brain activity concentrated in a lower frequency range - below the recurrence of sensory events - in response to acoustic rhythm. In contrast, when the rhythm is conveyed through touch, brain responses comparatively exhibit higher frequency activity corresponding to the faithful tracking of each individual events of the tactile rhythm. Most importantly, these auditory-specific slow fluctuations feature a periodization of rhythmic inputs, compatible with behavior. This higher-level neural processing of rhythmic input could thus reflect internal representations of the beat that are not necessarily shared across sensory modalities, in line with the concept of auditory dominance in temporal event perception and motor entrainment to rhythm. The current study thus opens a promising avenue to gain fundamental knowledge on high-level multimodal perception and motor entrainment processes specific to humans.

neuroscience↗

bioRxiv2024

Characterization of a GpsB-associated regulator of PBP1a reveals the organization of the cell wall remodeling complex of Streptococcus pneumoniae

Class A PBPs (aPBPs) play a key role in the biosynthesis and remodeling of peptidoglycan, the main component of the bacterial cell wall. The human bacterial pathogen Streptococcus pneumoniae produces three aPBPs, which are regulated to maintain the bacteriums ovoid shape. Although their exact functions remain unclear, evidence suggests that PBP1a and PBP2a activities are closely coordinated. In this study, we elucidated the function of an unknown function protein named GarP (GpsB-associated regulator of PBP1a), in the regulation of PBP1a activity. We showed that GarP localizes to the division septum and its absence leads to morphological defects. We further identified a GpsB-binding motif in GarP as well as in PBP2a, the PG deacetylase PgdA and the muramidase MpgA. Our analysis of genetic and protein interactions, combined with cell imaging, supports a model of a molecular complex that coordinates PG remodeling during S. pneumoniae cell division.

microbiology↗

bioRxiv2020

Virulence strategies of an insect herbivore and oomycete plant pathogen converge on host E3 SUMO ligase SIZ1 to suppress plant immunity

Pathogens and pests secrete proteins (effectors) to interfere with plant immunity through modification of host target functions and disruption of immune signalling networks. Importantly, molecular virulence strategies of distinct pathogens converge on a small set of regulators with central roles in plant immunity. The extent of convergence between pathogen and herbivorous insect virulence strategies is largely unexplored. We found that effectors from the oomycete pathogen, Phytophthora capsici, and the major aphid pest, Myzus persicae target the host immune regulator SIZ1, an E3 SUMO ligase. We show that the oomycete and aphid effector, which both contribute to virulence, feature different activities towards SIZ1. While M. persicae effector Mp64 increases SIZ1 protein levels, P. capsici effector CRN83_152 enhances SIZ1-E3 SUMO ligase activity in vivo. Loss of SIZ1 in host plants leads to reduced host susceptibility to aphids and an oomycete pathogen. Our results suggest convergence of distinct pathogen and pest virulence strategies on an E3 SUMO ligase to enhance host susceptibility.

plant biology↗