Biology subjects

Ramanoel, S.

Publications and source records attributed to Ramanoel, S..

13 recordsLinked to original sources

bioRxiv2026

Uncovering cognitive-motor adaptation to body visualization in immersive technologies trough their behavioral and electrophysiological correlates

Immersive technologies, encompassed within the x reality (XR) framework spanning the reality virtuality continuum, are emerging as tools to facilitate behavioral adaptation through interaction with controlled environments. Yet, how XR features shape users behavior remains poorly understood, particularly when a coordination between cognitive and motor demands is required. Among these features, body visualization (i.e., how the user body is rendered within the environment), is especially relevant to XR usages in rehabilitation and skill training, since body related feedback is known to strongly influence movement adaptation under cognitive motor interference. Still, whether and how different body visualization scenarios shape movement adaptation and what are the underlying neural processes, remains unclear. To address these questions, thirty healthy young adults performed a stepping task concurrently with an updating n back task under three body visualization scenarios (real body, no body, and a knee position cue) and four levels of dual tasks while we recorded high density mobile electroencephalography. The absence of body visualization impaired motor performance, reducing stepping accuracy and increasing omissions. Remarkably, a knee position cue alone restored performance to real body levels, without improving embodiment. This behavioral benefit co occurred with neural modulations reflecting enhanced conflict monitoring and adjusted motor preparation, evidenced by changes in the frontocentral N450 component and sensorimotor alpha and beta activity, respectively. These findings indicate that minimal body related visual cues, rather than full visualization, can support cognitive motor performance in XR, without altering embodiment. They position cueing as a practical design strategy for movement related XR usages and motivate further investigations of other forms of body related feedback to optimize cognitive motor behavior.

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bioRxiv2026

The role of cognitivo-motor interaction in landmark reliance and navigational deficits in older adults

Declining spatial navigation abilities are a critical hallmark of aging, where the loss of spatial abilities precedes global cognitive impairment. While navigational decline is traditionally attributed to deficits in higher-order cognitive functions, emerging cognitive-motor frameworks suggest that age-related sensorimotor alterations play a significant, yet previously overlooked, role. Here, we investigate the coupling between locomotor integrity and navigation by combining an immersive virtual-reality path-integration paradigm with systematic manipulations of landmark availability and reliability, while recording gait kinematics alongside neural dynamics using high-density mobile-EEG from 30 young and 32 older adults. We demonstrate that older adults accumulate angular homing error more rapidly than younger adults, a deficit linked to altered gait dynamics. These age-dependent differences are reflected in increased mid-frontal theta activity, highlighting a robust coupling between gait-related sensorimotor alterations and decline in navigation. Older adults also exhibited increased reliance on visual landmarks, and particularly those with degraded gait, yet this compensatory reweighting of navigational cues remained less efficient and less precise than in younger adults. These findings highlight sensorimotor gait alterations as a central determinant of age-related navigation deficits, challenging the traditional separation of motor and cognitive domains and identifying locomotor integrity as a critical target for preserving spatial navigation abilities.

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bioRxiv2026

Distinct cortical regions support the coding of order across visual and auditory working memory

Spatialization in working memory refers to the spatial coding of non-spatial information along a mental horizontal line when encoding verbal material. This phenomenon is thought to support working memory by facilitating order encoding. Although it has been observed for both visually and auditorily presented stimuli, no direct comparison has yet examined whether these modalities rely on similar neural mechanisms. In this study, we investigated whether spatialization in visual and auditory modalities involves shared or distinct patterns of activity within the working-memory network. Forty-nine participants performed both a visual and an auditory working memory SPoARC task of the same verbal material, allowing to study the cortical patterns associated with distinct serial positions at both encoding and recognition across sensory modalities. Whole-brain analyses revealed similar frontoparietal networks across conditions. In addition, a representational similarity analysis (RSA) was conducted to assess the similarity of neural patterns between early and late serial positions in a sequence and across sensory modalities. This multivoxel pattern analysis revealed modality-dependent patterns distinguishing early and late positions in the inferior frontal gyrus. Additional modality-specific effects were observed in the anterior intraparietal sulcus in the visual modality and in the posterior hippocampus in the auditory modality. Drawing on the framework proposed by Bottini & Doeller (2020), we propose that order decoding in the IPS might reflect a low-dimensional spatial coding of order (e.g., along a horizontal axis), whereas order decoding in the hippocampus might reflect higher-dimensional spatial representations or temporal representations.

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bioRxiv2026

Aging amplifies the influence of spatial contextual information on visual scene processing

Older adults rely increasingly on prior knowledge to make sense of their deteriorating representation of the visual world, but how this shapes scene perception and spatial reorientation remains unclear. To address this issue, 28 young and 25 older adults viewed artificially generated rooms either before or after learning the position of a goal hidden in an adjacent room. We manipulated both the number and the eccentricity of navigational affordances (i.e., open doors) to investigate the interaction between bottom-up scene features and top-down spatial knowledge. Consistent with previous findings, younger adults showed decreased performance as the number of open doors increased, but only after learning the goals position, indicating a top-down interaction with the automatic processing of affordances. Door eccentricity did not affect this interaction, suggesting our findings were not due to a distractor effect. In older adults, this interaction between prior spatial information and navigational affordances was markedly amplified: reaction times increased at twice the rate observed in younger adults. These findings show that prior spatial knowledge interacts with the automatic extraction of navigational affordances, and that this influence is markedly amplified with age. While prior knowledge helps stabilize perception when sensory processing becomes less reliable, it can also increase the processing time for complex scenes, particularly when multiple action possibilities are present. By revealing how aging shifts the balance between top-down and bottom-up mechanisms, these results refine models of age-related spatial navigation decline and highlight a trade-off whereby increased reliance on prior knowledge supports perception but can also slow interaction with complex environments.

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bioRxiv2026

Reinforced Hippocampus-Accumbens pathway marks a shift towards cognitive decline in aging

Aging triggers early functional alterations in brain circuits that precede cognitive impairment, yet the underlying mechanisms remain unclear. Spatial navigation and memory, among the earliest affected, depend on hippocampus and downstream targets such as the nucleus accumbens (NAc), which integrates spatial and motivational information to guide goal-directed behaviors. Here we identify age-related, sex-dependent changes of the dorsal hippocampus-NAc (dHPC[->]NAc) pathway. Combining optogenetics with electrophysiology, chemogenetics, and behavioral analyses in mice, we show that aging shifts excitation-inhibition balance in dorsal CA1 toward pyramidal neuron hyperexcitability, strengthening hippocampal outputs. This selectively enhances synaptic drive onto D1 receptor-expressing medium spiny neurons and involves a previously unrecognized long-range parvalbumin-expressing glutamatergic projection. Reducing dHPC[->]NAc excitability improves memory in aged mice. In humans, fMRI reveals heightened posterior hippocampal activity and stronger pHPC-NAc coupling during navigation. Together, we uncover a targetable pathway acting in an intervention-sensitive window of aging to correct negative cognitive trajectories.

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bioRxiv2025

Theta activity in the RSC anchors space to the body cardinal axes

Understanding human navigation in ecological, freely moving conditions requires uncovering how the brain anchors directional representations to the bodys orientation. Using high-density mobile electroencephalography and immersive virtual reality during goal-directed whole-body rotations, we found that theta bursts reconstructed in the retrosplenial complex (RSC) encode both acceleration and alignment with the bodys principal axes. Crucially, this body-axis-anchored neural signal emerged only during goal-directed rotations, and its strength correlated with individual navigation performance, suggesting an adaptive mechanism which provides a stable egocentric scaffold for orientation. These results provide compelling evidence for a self-motion-gated, body-centered reference frame that supports efficient navigation, and bridge the gap between static neuroimaging findings in humans and rodent research on RSC geometry codes. Overall, our findings advance an embodied, mechanistic account of human navigation, opening new avenues for investigating brain dynamics in naturalistic, movement-rich settings using non-invasive neural recordings.

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bioRxiv2025

Neurocognitive dynamics of translating information from a spatial map into action

How do we translate information from a spatial map to action in our immediate surroundings? Despite the widespread use of various tools for orientation, from paper maps to GPS, this fundamental question remains unanswered in our understanding of human spatial navigation. To investigate this, we implemented a perspective-taking task in immersive virtual reality combined with mobile EEG, aiming to disentangle the neurocognitive processes involved. Thirty-eight young adults were presented with a virtual 2D map in which we manipulated both the perspective shift and the physical angle of rotation required to align with a target, as well as the congruency between these two variables. Behaviourally, angular error during pointing increased slightly and linearly with perspective shift. However, the relationship between rotation angle and accuracy revealed a non-linear pattern, with better performance around the antero-posterior bodily-axis. Regarding congruency, angular error increased for incongruent trials, but only when the perspective-taking angle exceeded 90{degrees}. At the neural level, activity in the retrosplenial complex (RSC) revealed a sequential organization with alpha-band modulation during perspective shift, followed by beta-band activity reflecting preparation for the required physical rotation. In addition, incongruency between perspective-taking and physical rotation increased beta activity in the left temporo-parietal junction (lTPJ). Overall, these findings demonstrate the value of immersive virtual environments to investigate the neural correlates of real-world navigation and the complexity of perspective-taking mechanisms.

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bioRxiv2025

Theta activity supports landmark-based correction of naturalistic human path integration

How do humans integrate landmarks to update their spatial position during active navigation task? Using immersive virtual reality and high-density mobile EEG, we investigated the neural underpinnings of landmark-based recalibration during path integration. Our findings reveal that a briefly presented intramaze landmark effectively corrected accumulated homing errors. However, this effect was transient and less optimal when participants were highly confident in their self-motion-based spatial representation suggesting that internal priors hinder the assimilation of novel spatial cues. At the neural level, RSC theta-band activity supported these recalibration processes. When fine adjustments of the spatial representation were sufficient, landmark presentation elicited stronger theta-band activity and greater phase resetting compared to when substantial spatial updating was necessary. Our results also revealed motor-related theta activity that scaled with acceleration during rotational corrections, highlighting the dual role of theta in the flexible integration of multimodal signals, involved in both landmark-based spatial updating and self-motion encoding.

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bioRxiv2024

Where do I go? Decoding temporal neural dynamics of scene processing and visuospatial memory interactions using CNNs

Visual scene perception enables rapid interpretation of the surrounding environment by integrating multiple visual features related to task demands and context, which is essential for goal-directed behavior. In the present work, we investigated the temporal neural dynamics underlying the interaction between the processing of visual features (i.e., bottom-up processes) and contextual knowledge (i.e., top-down processes) during scene perception. We analyzed EEG data from 30 participants performing scene memory and visuospatial memory tasks in which we manipulated the number of navigational affordances available (i.e., the number of open doors) while controlling for similar low-level visual features across tasks. We used convolutional neural networks (CNN) coupled with gradient-weighted class activation mapping (Grad-CAM) to assess the main channels and time points underlying neural processing for each task. We found that early occipitoparietal activity (50-250 ms post-stimulus) contributed most to the classification of several aspects of visual perception, including scene color, navigational affordances, and spatial memory content. In addition, we showed that the CNN successfully trained to detect affordances during scene perception was unable to detect the same affordances in the spatial memory task after learning, whereas a similarly trained and tested model for detecting wall color was able to generalize across tasks. Taken together, these results reveal an early common window of integration for scene and visuospatial memory information, with a specific and immediate influence of newly acquired spatial knowledge on early neural correlates of scene perception.

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bioRxiv2024

Spatial contextual information modulates affordance processing and early electrophysiological markers of scene perception

Scene perception allows humans to extract information from their environment and plan navigation efficiently. The automatic extraction of potential paths in a scene, also referred to as navigational affordances is supported by scene-selective regions (SSRs) that enable efficient human navigation. Recent evidence suggests that the activity of these SSRs can be influenced by information from adjacent spatial memory areas. However, it remains unexplored how these contextual information could influence the extraction of bottom-up information, such as navigational affordances, from a scene and the underlying neural dynamics. Therefore, we analyzed event-related potentials (ERPs) in 26 young adults performing scene and spatial memory tasks in artificially generated rooms with varying numbers and locations of available doorways. We found that increasing the number of navigational affordances only impaired performance in the spatial memory task. ERP results showed a similar pattern of activity for both tasks, but with increased P2 amplitude in the spatial memory task compared to the scene memory. Finally, we reported no modulation of the P2 component by the number of affordances in either task. This modulation of early markers of visual processing suggests that the dynamics of SSR activity are influenced by a priori knowledge, with increased amplitude when participants have more contextual information about the perceived scene. Overall, our results suggest that prior spatial knowledge about the scene, such as the location of a goal, modulates early cortical activity associated with scene-selective regions, and that this information may interact with bottom-up processing of scene content, such as navigational affordances.

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bioRxiv2023

Age-related differences in electrophysiological correlates of visuospatial reorientation

Spatial navigation abilities decline with age. Recent studies revealed a specific impairment in landmark-based reorientation, linked to changes in scene-selective brain regions activity. While fMRI studies suggest that these cortical modulations might be compensatory, a more precise investigation of the brain dynamics associated with visuospatial processing is warranted. We analyzed Event-Related Potentials and Event-Related Spectral Perturbations recorded from electrodes over scene-selective regions. 28 young adults and 28 older adults completed a desktop-based reorientation task using landmarks. Our findings show poorer reorientation performance among older adults. Signatures of age-related modulation of EEG activity imputable to scene-selective regions were predominantly observed within the right hemisphere. EEG analysis disclosed a tripartite worsening of scene processing accounting for older adults difficulties. Firstly, a delayed and reduced P1 component likely reflects a slower and less efficient stimulus discrimination. Secondly, an increased N1 amplitude and theta-band activity suggest a higher demand on cognitive resources associated with more effortful processing of visuospatial information. Thirdly, a decreased P2 amplitude may imply deficient attentional mechanisms to select task-relevant stimuli.

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bioRxiv2023

Scene-selective regions encode the vertical position of navigationally relevant information in young and older adulthood

Position within the environment influences the navigational relevance of objects. However, the possibility that vertical position represents a central object property has yet to be explored. Considering that the upper and lower visual fields afford distinct types of visual cues and that scene-selective regions exhibit retinotopic biases, it is of interest to elucidate whether the vertical location of visual information modulates neural activity in these high-level visual areas. The occipital place area (OPA), parahippocampal place area (PPA) and medial place area (MPA) demonstrate biases for the contralateral lower visual field, contralateral upper visual field, and contralateral hemifield, respectively. Interesting insights could also be gained from studying older adulthood as recent work points towards an age-related preference for the lower visual field. In the present study, young and older participants learned the position of a goal in a virtual environment that manipulated two variables: the vertical position of navigationally-relevant objects and the presence of non-relevant objects. Results revealed that all three scene-selective regions parsed the vertical position of useful objects independently of their subtending retinotopic biases. It therefore appears that representations in the higher-level visual system combined information about vertical position and navigational value for wayfinding purposes. This property was maintained in healthy aging emphasizing the enduring significance of visual processing along the vertical dimension for spatial navigation abilities across the lifespan.

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bioRxiv2020

Modulation of spatial cue processing across the lifespan: a geometric polarization of space restores allocentric navigation strategies in children and older adults

The impact of development and healthy aging on spatial cognition has been traditionally attributed to a difficulty in using allocentric strategies and a preference for egocentric ones. An alternative possibility, suggested by our previous works, is that this preference is actually conditioned by the spatial cues (e.g. geometric of landmark cues) present in the environment rather than a strategic choice per se. We tested this prediction by having 79 subjects (children, young and older adults) navigating a Y-maze composed either of landmarks or geometric cues, with an immersive head-mounted display that allows us to record both head and eye movements. Our results show that when the performance is based on landmarks solely, children and older adults exhibit a deficit in using allocentric strategies when compared to young adults. Hence, an inverted U-profile of allocentric strategies was observed across the lifespan. This was not due to a default of attention to the landmarks, as evidenced by analysis of gaze dynamics. When geometric were provided, however, older adults and children used allocentric strategies in the same proportion as young adults. They were, in addition, as efficient and quick to implement the strategy. We thus propose a reinterpretation of the previous data in the literature, whereby reference to geometric cues is the default mode for spatial representations, which is immune to age, whereas spatial representations fail to be anchored on landmarks early in development and later in aging. This new interpretation has the potential to reunify several data from the literature, ranging from spatial cues processing to strategy preference, and including other spatial skills like path integration and route learning.

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