Biology subjects

Hehemann, L.

Publications and source records attributed to Hehemann, L..

5 recordsLinked to original sources

bioRxiv2026

Spontaneous Perceptual Reversals reflect in Internal Rhythms, Not Metabolic Shifts or Evoked Responses

The perceptual interpretation of a static image, such as the Necker cube, can change spontaneously, resulting in endogenously driven changes in perception. We studied how different peripheral markers of the bodys physiological state, as well as time-resolved markers of EEG-derived brain activity, modulate around such spontaneous changes in perception. Specifically, we quantified the time course of heart rate, respiration rate, respiration phase, pupil size, EEG evoked responses, and EEG time-frequency activity around spontaneous perceptual reversals, and tested how these signals differ between the two interpretations of the Necker cube. Our results show that signals relating to the bodys and brains momentary state differ between the two perceptual interpretations, including pupil size, respiration phase, and rhythmic EEG activity. In contrast, signals relating to metabolic state or external stimuli, including respiration rate, heart rate and EEG evoked responses, did not differ between perceptual interpretations, but were consistently modulated around these. This corroborates the notion that spontaneous changes in perception are related to specific and coordinated windows in the cardiorespiratory cycle and neural markers of arousal or top-down processing. These windows are differentially expressed across interacting physiological systems, highlighting the intricate link between perception, brain activity and bodily physiology.

neuroscience↗

bioRxiv2025

Effects of Short-Term Breathwork on Respiration and Cognition

Respiration is a unique physiological process that can operate automatically but can also be deliberately used to modulate the bodily state. Importantly, respiration is deeply intertwined with neural processes, influencing processes from arousal and attention to executive control. Although structured respiration (breathing practice) has been exploited for centuries, the immediate consequences of short periods of structured respiration for sensation and cognition remain poorly understood. The present study examined how brief, one-minute episodes of structured respiration affect respiration and performance in a subsequent sensory-cognitive task. Across two experiments, participants engaged in structured breathing practices manipulating either respiratory frequency (slow breathing vs. fast breathing) or the inhalation-exhalation ratio (short inspiration-long expiration; long inspiration-short expiration) prior to performing a visual emotion discrimination task. Immediately after breathing practice, participants respiration deviated from their baseline: each technique resulted in specific deviations of respiratory frequency, inhalation-exhalation ratio, or the occurrence of atypical respiratory cycles, suggesting technique-specific returns to regular respiration. During the subsequent emotion response accuracy or reaction times did not differ between breathing practices. However, we observed transient improvements in reaction times immediately following all practices, suggesting a brief facilitation of attentional or sensorimotor responsiveness following conscious breathing. Our findings indicate that even brief, consciously controlled respiration can transiently influence cognitive performance, highlighting the role of voluntary respiratory modulation in shaping brain function and behavior.

animal behavior and cognition↗

bioRxiv2025

The alignment of respiration to sensory-motor events is shaped by expected effort.

Humans often align their respiration with external events, a phenomenon thought to optimize neural resources for perception and action. Indeed, in sensory-cognitive experiments participants tend to align their respiration to the upcoming expected trials and their respiratory phase relates to neurophysiological processes reflecting changes in neural excitation, attention or arousal. However, it remains unclear whether this alignment is a passive entrainment to a tasks overall rhythm or an active process selectively aligning respiration based on the demands of individual events. We here tested this by recording respiration during three visual discrimination experiments that manipulated trial importance by either imposing different response deadlines or by manipulating trial value and difficulty. Our results show that participants align their respiration more consistently around stimulus onset for trials with short deadlines or trials presenting high-value and high-difficulty. These findings demonstrate that respiratory alignment is dynamically modulated on a trial-by-trial basis according to the anticipated required effort or task demands. Hence we conclude that respiration serves as an active tool to strategically allocate cognitive resources for sensory-motor challenges.

neuroscience↗

bioRxiv2024

The respiratory phase modulates task-related neural representations of visual stimuli

We investigate how respiration influences cognition by examining the interaction between respiratory phase and task-related brain activity during two visual categorization tasks. While prior research shows that cognitive performance varies along the respiratory cycle, the underlying neurophysiological mechanisms remain poorly understood. Though some studies have shown that large-scale neural activity reflecting changes in the excitation-inhibition balance is co-modulated with the respiratory cycle, it remains unclear whether respiration directly shapes the quality by which task-relevant sensory information is encoded. We address this gap by applying single-trial multivariate analyses to EEG data obtained in humans, allowing us to track how respiration modulates the sensory evidence in this neurophysiological signal. Confirming previous studies, our data show that participants performance varies with the respiratory phase prior and during a trial. Importantly, they also suggest that respiration directly influences the sensory evidence carried by parieto-occipital processes emerging around 300 to 200 ms prior to participants responses. Hence, respiration and sensory-cognitive processes are not only highly intertwined but respiration directly facilitates the representation of behaviourally-relevant signals in the brain.

neuroscience↗

bioRxiv2024

Respiration shapes response speed and accuracy with a systematic time lag

Sensory-cognitive functions are intertwined with physiological processes such as the heart beat or respiration. For example, we tend to align our respiratory cycle to expected events or actions. This happens during sports but also in computer-based tasks and systematically structures respiratory phase around relevant events. However, studies also show that trial-by-trial variations in respiratory phase shape brain activity and the speed or accuracy of individual responses. We show that both phenomena, the alignment of respiration to expected events and the explanatory power of the respiratory phase on behaviour co-exist. In fact, both the average respiratory phase of an individual relative to the experimental trials and trial-to-trial variations in respiratory phase hold significant predictive power on behavioural performance, in particular for reaction times. This co-modulation of respiration and behaviour emerges regardless of whether an individual generally breathes faster or slower and is strongest for the respiratory phase about two seconds prior to participants responses. The persistence of these effects across 12 datasets with 277 participants performing sensory-cognitive tasks confirm the robustness of these results, and suggest a profound and time-lagged influence of structured respiration on sensory-motor responses.

neuroscience↗