Biology subjects

Ziane, C.

Publications and source records attributed to Ziane, C..

3 recordsLinked to original sources

bioRxiv2026

Distinct Neural Signatures Underlie Finger Tapping and Walking to Auditory Rhythms

Neural oscillations synchronize with rhythmic stimuli, shaping perception and action. Auditory-motor synchronization (AMS) enhances this process but most evidence comes from finger tapping, an attentionally demanding voluntary behaviour. Whether motor-driven modulation of neural synchronization generalizes to more automatic movements like walking remains unclear. In this study, we used mobile EEG to compare neural synchronization to auditory rhythms during tapping and walking in 40 older male and female participants, manipulating cognitive load (single vs. dual task) and task instructions (synchronize with vs. ignore metronome). EEG components attuned to metronome frequencies were extracted and complementary measures of neural synchronization were computed (phase coupling to the stimulus, power at the stimulus frequency, and the stability of instantaneous frequencies). Both movements enhanced neural synchronization relative to passive listening. Neural synchronization was further increased by instructions to synchronize, but only during tapping. This instruction-facilitating effect was lost in dual tasks. These findings suggest that AMS recruits movement-dependent neural and cognitive mechanisms, depending on where AMS lies on a continuum from voluntary-controlled to automatic forms of coordination, with implications for rhythm-based interventions in aging. Significance statementNeural coupling to stimuli in the environment shape perception and action, but its dependence on movement type and cognitive control is poorly understood. Using mobile EEG, we show that both finger tapping and walking enhance neural coupling to the auditory stimuli, but tapping is uniquely modulated by task factors. Our findings suggest that cortical involvement during rhythmic motor tasks differs for voluntary (tapping) and automatic (walking) behaviours. As gait can move from being mostly automatic to voluntary-controlled (e.g., under heightened cognitive load, in motor disorders), it offers a unique opportunity to study the dynamic interactions between sensory, motor, and cognitive processes supporting neural coupling to auditory stimuli.

neuroscience↗

bioRxiv2023

Corticopostural functional and effective connectivity reveal cortical control of postural sway velocity during quiet standing

BackgroundDespite a large body of evidence showing the involvement of the sensorimotor cortex in postural control, its exact role remains unclear. Models of postural control outcomes suggested that the velocity of the center of pressure is a crucial parameter to maintain balance. Inspired by corticokinematic coherence, we hypothesized that cortical oscillations and the velocity of the center of pressure (CoP) would synchronize and that this synchronization would increase with postural task difficulty during quiet standing. MethodsWe compared the magnitude of coherence and Granger causality computed between brain oscillations recorded with electroencephalography and the center of pressure velocity in the Delta and Theta frequency bands obtained from 23 participants performing four quiet standing tasks with various levels of difficulty. The effect of postural task difficulty and information flow direction were tested with a linear mixed model while non-parametric correlations were computed between coherence magnitude and postural performance measured by 95% confidence ellipse area and mean center of pressure velocity. ResultsWe found significant coherence between the Cz EEG electrode and CoP velocity in the Delta and Theta frequency bands. This EEG-CoP velocity coherence significantly increased with task difficulty in the Delta (F = 18.8, p < 0.001) and Theta (F = 7.83, p < 0.001) bands. Granger causality significantly increased with task difficulty (F = 12.5, p < 0.001) and was higher in the efferent than afferent direction (F = 78, p < 0.001). The 95% confidence ellipse area was correlated to coherence magnitude in the most difficult condition. Participants showing significant Granger causality in the afferent direction showed more stable postural outcomes. ConclusionOur results confirm that the CoP velocity has a crucial role in postural control through its synchronization with sensorimotor cortex oscillations. The efferent information predominance suggests that posture is partly controlled by the sensorimotor cortex by a mechanism named corticopostural coherence. Our results show that this corticopostural coherence could represent a mechanism for controlling balance during quiet standing.

neuroscience↗

bioRxiv2021

Attentional brain rhythms during prolonged cognitive activity

As routine and lower demand cognitive tasks are taken over by automated assistive systems, human operators are increasingly required to sustain cognitive demand over long periods of time. This has been reported to have long term adverse effects on cardiovascular and mental health. However, it remains unclear whether prolonged cognitive activity results in a monotonic decrease in the efficiency of the recruited brain processes, or whether the brain is able to sustain functions over time spans of one hour and more. Here, we show that during working sessions of one hour or more, contrary to the prediction of a monotonic decline, behavioral performance in both humans and non-human primates consistently fluctuates between periods of optimal and suboptimal performance at a very slow rhythm of circa 5 cycles per hour. These fluctuations are observed in both high attentional (in non-human primates) and low attentional (in humans) demand conditions. They coincide with fluctuations in pupil diameter, indicating underlying changes in arousal and information-processing load. Accordingly, we show that these rhythmic behavioral fluctuations correlate, at the neurophysiological level, with fluctuations in the informational attention orientation and perception processing capacity of prefrontal neuronal populations. We further identify specific markers of these fluctuations in LFP power, LFP coherence and spike-field coherence, pointing towards long-range rhythmic modulatory inputs to the prefrontal cortex rather than a local prefrontal origin. These results shed light on the resilience of brain mechanisms to sustained effort and have direct implications on how to optimize high cognitive demand working and learning environments.

neuroscience↗