Dernières publications HAL

Sensory attenuation refers to reduced neural and perceptual responses to self-generated tones compared to tones triggered externally. Our previous study showed that the strength of action-outcome coupling (SAOC) influences the perceptual biases for sound intensity. Indeed, we observed that the overall perceived intensity of tones triggered by keypresses (strong coupling) was attenuated, in contrast to tones triggered by ocular saccades (weak coupling). Building on this earlier study, we investigated the influence of SAOC on perceptual attenuation for auditory pitch. Indeed, to date, no behavioral study has demonstrated any sensory attenuation effect regarding pitch perception, although it has been suggested that attenuation may manifest in this case as a change in the ability to perceive pitch differences (discrimination sensitivity). A total of 140 participants were divided into three groups. They performed a pitch discrimination task in which test tones of varying frequency were triggered either by an ocular saccade, a keypress, or played after a cue (no action required, or “passive” group). Test tones were presented 150 ms or 1500 ms after the action (or cue). Results revealed lower discrimination sensitivity in the keypress group compared to the passive group (Cohen's d = 0.66). In contrast, no significant difference was found between the saccade and passive groups. Also, in the keypress group only, we observed a small effect of delay (Cohen's d = 0.14), with reduced sensitivity at the shorter action-outcome interval. This reduced perceptual sensitivity for keypress-triggered tones may reflect sensory attenuation (sounds are more difficult to differentiate), possibly due to predictive mechanisms. Importantly, the absence of a significant difference between the saccade and passive groups, together with the small size of the delay effect, suggests that this reduction in sensitivity cannot be explained by dual-task interference alone. These results align with our previous findings suggesting that a strong action-outcome coupling is necessary to observe perceptual attenuation.

Preparing an eye movement is known to enhance visual perception at its goal location, improving the processing of several stimulus features. Previous findings indicate that saccade preparation also reduces the Size-Eccentricity Effect, i.e. the classic underestimation of object size in peripheral vision (Laaboudi et al., 2025). Importantly, this perceptual enhancement was observed about 200 ms before saccade onset, earlier than the typical time window reported for pre-saccadic enhancement. We therefore sought to clarify the temporal profile of this effect. In a first experiment, 15 participants compared a briefly presented peripheral disk with a reference disk shown at the saccade landing position. By manipulating the timing of an auditory go-signal, we varied the delay between stimulus offset and saccade onset from 50 to 550 ms. Separate fixation trials assessed peripheral size perception without saccade preparation. Replicating our previous findings, perceived size in the periphery was more accurate in saccade than in fixation trials. However, this perceptual enhancement did not depend on saccade timing. Because the effect remained stable, in a second experiment, we tested whether it reflected other, cue-driven attentional mechanisms. In particular, endogenous attention is generally more sustained over time than exogenous and pre-saccadic attention. To explore this, we extended our paradigm from a single peripheral location to four possible locations. In an exogenous condition, cues validly or invalidly indicated the test disk location with equal probability, whereas in an endogenous condition one location was favored (75%). Preliminary results revealed no reliable cueing effect, but a systematic perceptual enhancement associated with saccade preparation. Together, these findings indicate that the increase in peripheral perceived size is robust across a broader temporal window than expected for typical pre-saccadic enhancement and is more specifically linked to oculomotor preparation than to the covert cueing manipulations tested here.

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People with bipolar disorder (BD) present with mood instability resulting from more frequent and intense emotions in response to environmental conditions relative to healthy subjects. The aim of this study was to investigate the time course of emotion regulation strategies, distraction, and reappraisal in euthymic BD patients (i.e., normal mood range) using electroencephalography (EEG). Fourteen BD patients and 13 matched healthy controls took part in an experiment constituting three conditions, i.e., a passive viewing of positive, negative, and neutral pictures, and two regulation conditions, one with a reappraisal strategy and the other with a distraction strategy. Critically, the ERP results indicated that during passive viewing, the Late Positive Potential (LPP) was larger in BD patients compared with healthy controls, but only for neutral pictures. During emotion regulation, LPP amplitude was reduced in distraction conditions compared with viewing ones, especially for negative emotions in both patients and controls. Importantly, LPP was reduced in reappraisal conditions compared with passive viewing in an early time window for negative emotions and in a later time window for positive emotions in controls but not in patients. Our findings showed that the temporal dynamics of emotion regulation by reappraisal are faster for negative than for positive emotions in controls but not in BD patients.

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