Biology subjects

Djebbara, Z.

Publications and source records attributed to Djebbara, Z..

6 recordsLinked to original sources

bioRxiv2026

Architecture shapes event boundaries: Theta dynamics of event segmentation during spatial transitions

Human experience unfolds continuously, yet it is remembered and understood as a sequence of discrete events. How the brain segments this stream of experience, particularly under naturalistic conditions, remains poorly understood. Here we investigate the neural dynamics associated with event boundaries during active navigation through architectural transitions. Using mobile electroencephalography combined with virtual reality, we analyzed data from participants freely walking between rooms and repeatedly crossing doorways. Time-frequency analysis of source-localized neural activity revealed a robust increase in theta-band power (4-8 Hz) over temporo-occipital and parietal regions approximately 300-450 ms after passing through a doorway. This effect was consistent across participants and independent component clusters, indicating a reliable neural signature of architectural transitions. We interpret this theta response within frameworks of event segmentation and Bayesian inference, suggesting that doorways trigger a transient reconfiguration of distributed neural networks when ongoing predictions can no longer be maintained and a new event model must be inferred. By preserving the natural coupling between perception, movement, and environmental structure, our findings demonstrate that architecture provides meaningful boundaries that shape brain dynamics and the organization of experience. More broadly, this work highlights the power of naturalistic experimentation and positions architectural space as an active medium for investigating how the brain structures events.

neuroscience↗

bioRxiv2025

Attentional cueing effects are reversed during locomotion

Everyday human cognition and behaviour evolved in dynamic and ever-changing environments, but static paradigms still dominate experimental research despite concerns about generalisability of the results. In the case of attention, traditional stationary studies show that pre-orienting attention with spatial cues leads to faster, more accurate responses. However, how movement and environmental features shape such attentional processes in everyday behaviour remains unknown. Here we show that active movement through curved corridors reverses the typical spatial attention effect, with faster response times and higher accuracy for stimuli incongruent to implicit spatial cues provided by the movement direction, contradicting previous findings from static settings. We found that early (N1) and late (P3) attention-related electrophysiological responses were modulated by environmental features and motor demands. The posterior N1-component, reflecting visuo-spatial attention, showed decreasing amplitudes as turning angles and motor-control demands increased for congruent stimuli appearing on the side of the turning direction. Similarly, the P3-complex varied with motor and visual processing demands for congruent stimuli, showing decreased amplitudes as motor-control demands increased. We propose that congruent stimuli, displayed against a dynamically changing visual context, increase pulvino-cortical processing load and slowing early visual processing that affect behavioural responses. Incongruent stimuli, however, are displayed against a predictable context allowing faster target processing. These findings challenge attentional mechanisms assumed consistency across static and dynamic settings, revealing instead their dependence on behavioural and environmental context. We advocate for naturalistic paradigms, arguing that moving beyond static experiments could reshape core views on cognition and behaviour.

neuroscience↗

bioRxiv2023

Human Brain Dynamics Dissociate Early Perceptual and Late Motor-Related Stages of Affordance Processing

Affordances, the opportunity for action offered by the environment to an agent, are vital for meaningful behavior and exist in every interaction with the environment. There is an ongoing debate in the field about whether the perception of affordances is an automated process. Some studies suggest that affordance perception is an automated process that is independent from the visual context and bodily interaction with the environment, while others argue that it is modulated by the visual and motor context in which affordances are perceived. The present paper aims to resolve this debate by examining affordance automaticity from the perspective of sensorimotor time windows. We replicated a previous study on affordance perception in which participants actively moved through doors of different width in immersive 3D virtual environments. To investigate the impact of different forms of bodily interactions with an environment, i.e., the movement context (physical vs. joystick movement), we used the identical virtual environment from Djebbara and colleagues (2019) but displayed it on a 2D screen with participants moving through different wide doors using the keys on a standard keyboard. We compared components of the event-related potential (ERP) from the continuously recorded electroencephalogram (EEG) that were previously reported to be related to affordance perception of architectural transitions (passable and impassable doors). Comparing early sensory and later motor-related ERPs, our study replicated ERPs reflecting early affordance perception but found differences in later motor-related components. These results indicate a shift from automated perception of affordances during early sensorimotor time windows to movement context dependence of affordance perception at later stages suggesting that affordance perception is a dynamic and flexible process that changes over sensorimotor stages.

neuroscience↗

bioRxiv2022

The BeMoBIL Pipeline for automated analyses of multimodal mobile brain and body imaging data

Advancements in hardware technology and analysis methods allow more and more mobility in electroencephalography (EEG) experiments. Mobile Brain/Body Imaging (MoBI) studies may record various types of data such as motion or eye tracking in addition to neural activity. Although there are options available to analyze EEG data in a standardized way, they do not fully cover complex multimodal data from mobile experiments. We thus propose the BeMoBIL Pipeline, an easy-to-use pipeline in MATLAB that supports the time-synchronized handling of multimodal data. It is based on EEGLAB and fieldtrip and consists of automated functions for EEG preprocessing and subsequent source separation. It also provides functions for motion data processing and extraction of event markers from different data modalities, including the extraction of eye-movement and gait-related events from EEG using independent component analysis. The pipeline introduces a new robust method for region-of-interest-based group-level clustering of independent EEG components. Finally, the BeMoBIL Pipeline provides analytical visualizations at various processing steps, keeping the analysis transparent and allowing for quality checks of the resulting outcomes. All parameters and steps are documented within the data structure and can be fully replicated using the same scripts. This pipeline makes the processing and analysis of (mobile) EEG and body data more reliable and independent of the prior experience of the individual researchers, thus facilitating the use of EEG in general and MoBI in particular. It is an open-source project available for download at https://github.com/BeMoBIL/bemobil-pipeline which allows for community-driven adaptations in the future.

neuroscience↗

bioRxiv2020

Architectural Affordance Impacts Human Sensorimotor Brain Dynamics

Action is a medium of collecting sensory information about the environment, which in turn is shaped by architectural affordances. Affordances characterize the fit between the physical structure of the body and capacities for movement and interaction with the environment, thus relying on sensorimotor processes associated with exploring the surroundings. Central to sensorimotor brain dynamics, the attentional mechanisms directing the gating function of sensory signals share neuronal resources with motor-related processes necessary to inferring the external causes of sensory signals. Such a predictive coding approach suggests that sensorimotor dynamics are sensitive to architectural affordances that support or suppress specific kinds of actions for an individual. However, how architectural affordances relate to the attentional mechanisms underlying the gating function for sensory signals remains unknown. Here we demonstrate that event-related desynchronization of alpha-band oscillations in parieto-occipital and medio-temporal regions covary with the architectural affordances. Source-level time-frequency analysis of data recorded in a motor-priming Mobile Brain/Body Imaging experiment revealed strong event-related desynchronization of the alpha band to originate from the posterior cingulate complex and bilateral parahippocampal areas. Our results firstly contribute to the understanding of how the brain resolves architectural affordances relevant to behaviour. Second, our results indicate that the alpha-band originating from the posterior cingulate complex covaries with the architectural affordances before participants interact with the environment. During the interaction, the bilateral parahippocampal areas dynamically reflect the affordable behaviour as perceived through the visual system. We conclude that the sensorimotor dynamics are developed for processing behaviour-relevant features in the designed environment.

neuroscience↗

bioRxiv2019

Sensory-motor brain dynamics reflect architectural affordances

Anticipating meaningful actions in the environment is an essential function of the brain. Such predictive mechanisms originate from the motor system and allow for inferring actions from environmental affordances, the potential to act within a specific environment. Using architecture, we provide a unique perspective to the abiding debate in cognitive neuroscience and philosophy on whether cognition depends on movement or is decoupled from our physical structure. To investigate cognitive processes associated with architectural affordances, we used a Mobile Brain/Body Imaging approach recording brain activity synchronized to head-mounted virtual reality. Participants perceived and acted upon virtual transitions ranging from non-passable to easily passable. We demonstrate that early sensory brain activity, upon revealing the environment and before actual movement, differed as a function of affordances. Additionally, movement through transitions was preceded by a motor-related negative component also depended on affordances. Our results suggest that potential actions afforded by an environment influence perception.\n\nSIGNIFICANCE STATEMENTBy using electroencephalography and virtual reality, our research provide a unique perspective to the centurial open-ended debate in cognitive neuroscience and philosophy on the relation between cognition, movement and environment. Our results indicate that cortical potentials vary as a function of bodily affordances reflected by the physical environment. Firstly, the results of this study implies that cognition is inherently related to potential movement of the body, thus we advance that action is interrelated with perception, actively influencing the perceivable environment. Secondly, as cortical potentials are influenced by the potential to move, which in turn is the task of architectural design, architects holds largely a privilege of human health, and thus potentially capable of provoking and preventing physiological conditions.

neuroscience↗