Biology subjects

Bottini, R.

Publications and source records attributed to Bottini, R..

At least 19 recordsLinked to original sources

bioRxiv2026

Neural Dissociation of Cognitive Maps and Graphs in the Human Brain

Cognitive maps and graphs offer two distinct ways of organizing knowledge: maps arrange items within a spatial layout, whereas graphs thread them together through experiential transitions. However, spatial proximity and experiential contiguity are typically correlated, and content represented in one format can often be transformed into the other, making their neural representations difficult to disentangle. Here, we orthogonally manipulated Euclidean distance, indexing spatial proximity, and shortest-path distance, indexing experiential contiguity, within the same learned environment. Using fMRI and whole-brain searchlight representational similarity analysis, we identified dissociable representations of these two formats in the human brain. Euclidean distance was represented in the intraparietal sulcus, whereas shortest-path distance was represented in the hippocampal/parahippocampal region and in cortical areas that overlapped substantially with scene-selective regions. ROI analyses further supported the specificity of these representations across regions. Together, these findings provide neural evidence for a dissociation between cognitive maps and cognitive graphs.

neuroscience↗

bioRxiv2026

Eye movements reflect attentional navigation of number space without visual experience

Primates use eye movements to explore and gather information about their external, visual world. Similarly, even when there is nothing to see spontaneous eye movements reflect the structure and the exploration of internal, conceptual knowledge. However, it remains unclear what mechanism links eye movements to this internal search process. One possibility is that eye movements reflect visual imagery or visual exploration strategies used to explore conceptual knowledge. On the other hand, eye movements may reflect attentional movements in the conceptual space, which are independent from visual experience. Early blind individuals are a useful testbed for this hypothesis in that they never had access to functional vision, thus ruling out the influence of imagery or recycling of visual exploration strategies. To this end, we asked early blind individuals to perform a random number generation task while recording their eye movements. Using electrooculography (EOG), we found that eye movements track the exploration of the mental number line in both sighted and blind: participants moved their eyes to the right for positive changes in magnitude in the number sequence and to the left for negative changes, with eye movement amplitude scaling with the magnitude difference. Furthermore, sighted and early blind participants showed a similar temporal profile, with the effect peaking around 750 ms before number onset. These findings support the hypothesis that internally generated shifts of attention, rather than eye movements per se, drive the exploration of conceptual spaces.

neuroscience↗

bioRxiv2026

Lexical and Semantic Coding in the Occipital Cortex of Sighted and Blind

How early visual cortex (EVC) supports language and semantic processing in sighted and congenitally blind individuals remains debated. Some predict that blindness induces radical functional reorganization of EVC, whereas others suggest more modest scaling-up changes of a neurofunctional architecture present in sighted individuals. We recorded whole-head MEG in 19 early blind (EB) and 21 sighted adults (SC) listening to spoken adjectives belonging to different semantic categories (i.e., abstract, concrete visual, concrete non-visual) and performing lexical and semantic decision tasks. In the lexical task, lexical information (i.e., word vs pseudoword) could be reliably decoded in perisylvian language areas and the EVC of both groups, with group differences (EB > SC) localized to occipital areas between 0.4 and 0.8 s after word onset. During the semantic task, semantic category information could be decoded in a network overlapping with the canonical semantic system and encompassing the EVC of both groups, with group differences (EB > SC) localized to occipital areas between 0.9 and 1 s after stimulus onset. We further characterized EVC properties and showed that i) EVC semantic information decoding is task sensitive, with no above-chance decoding in EB or SC in the lexical task ii) in the blind EVC it was possible to decode abstract from concrete concepts but not visual from non-visual concepts, a profile similar to that of posterior cingulate areas, but different to anterior cingulate cortex which showed above chance classification for all semantic categories. These results suggest that deprived EVC is integrated into a distributed lexical-semantic network carrying behaviourally relevant semantic information, although to a different extent.

neuroscience↗

bioRxiv2025

Foraging in conceptual spaces: hippocampal oscillatory dynamics underlying searching for concepts in memory

How does the brain access stored knowledge? It has been proposed that conceptual search engages neurocognitive processes similar to foraging in physical space. We tested this idea using intracranial EEG in patients performing a verbal fluency task, where they spontaneously explored their own knowledge of the world, sampling words from semantic memory. We found that hippocampal theta power increased during conceptual search and scaled with the semantic distance between successive words, paralleling dynamics observed in spatial navigation. Critically, people transitioned between conceptual clusters, resembling transitions between resource patches in foraging behavior. These shifts were marked by enhanced theta-gamma coupling, both within the hippocampus and between the hippocampus and lateral temporal cortex, a key hub of the semantic network. These findings support a mechanistic account of memory search grounded in navigation and foraging principles, suggesting that the hippocampus orchestrates local computations and long-range interactions to enable flexible retrieval of conceptual knowledge.

neuroscience↗

bioRxiv2025

Spatial coding supports auditory conceptual navigation

Grid cells in human entorhinal cortex encode spatial layouts for real-world navigation, yet their role in conceptual navigation remains unclear. Here we show that mentally transforming tones within a purely auditory pitch-duration space engages spatial circuits, and that such resources are causally necessary. In Experiment 1, participants trained for five days to navigate through a purely conceptual pitch-duration auditory space, then underwent fMRI on Day 6. We observed a six-fold modulation of entorhinal BOLD signals aligned to each participants trajectory angles, similar to grid-cell firing in physical space. Stronger grid-like coding predicted larger training-related gains. In Experiment 2, a new cohort performed the same task under either a spatial or non-spatial interference load. Only the spatial condition selectively disrupted performance on trials requiring mental "movement," indicating a causal reliance on spatial resources. These findings provide evidence that auditory conceptual transformations recruit--and depend on--spatial grid-like computations in the entorhinal-hippocampal system, pointing to a domain-general role for spatial coding in organizing new knowledge along continuous dimensions.

neuroscience↗

bioRxiv2025

Representation of conceptual affordances in eye movements and the entorhinal cortex

Structural representations in the entorhinal cortex are a crucial feature of cognitive maps. However, a complete understanding of task structure often requires knowledge of the actions available at each state (analogous to the moves of different pieces on a chessboard). Moreover, action representations are key to several models of the hippocampal-entorhinal system. In this study, we tested whether the entorhinal cortex represents the actions that allow transitioning between states of a conceptual space. In particular, participants learned to transition between numerically-labelled states using different mathematical operations. Behaviourally, participants learned and generalised action information across states. Action information was also reflected in eye movements, indicating the active processing of the possible actions for a given state during the trials. Importantly, we found that neural pattern similarity in the right entorhinal cortex scaled with the similarity of action affordances across the states. This affordance representation was not explained by other properties of the task space such as link distance between the states or action magnitude. In sum, this study provides first evidence for the integration of action information into ocular and entorhinal representations of conceptual spaces, suggesting that these may not just store experiences, but provide information about how to explore knowledge.

neuroscience↗

bioRxiv2024

Neural Representation of Time across Complementary Reference Frames

Humans conceptualize time in terms of space, allowing flexible time construals from various perspectives. We can travel internally through a timeline to remember the past and imagine the future (i.e., mental time travel) or watch from an external standpoint to have a panoramic view of history (i.e., mental time watching). However, the neural mechanisms that support these flexible temporal construals remain unclear. To investigate this, we asked participants to learn a fictional religious ritual of 15 events. During fMRI scanning, they were guided to consider the event series from either an internal or external perspective in different tasks. Behavioral results confirmed the success of our manipulation, showing the expected symbolic distance effect in the internal-perspective task and the reverse effect in the external-perspective task. We found that the activation level in the posterior parietal cortex correlated positively with sequential distance in the external-perspective task but negatively in the internal-perspective task. In contrast, the activation level in the anterior hippocampus positively correlated with sequential distance regardless of the observers perspectives. These results suggest that the hippocampus stores the memory of the event sequences allocentrically in a perspective-agnostic manner. Conversely, the posterior parietal cortex retrieves event sequences egocentrically from the optimal perspective for the current task context. Such complementary allocentric and egocentric representations support both the stability of memory storage and the flexibility of time construals.

neuroscience↗

bioRxiv2023

Timecourse and source localization of abstract and concrete semantic representations.

Dual coding theories of knowledge suggest that meaning is represented in the brain by a double code, which comprises language-derived representations in the Anterior Temporal Lobe and sensory-derived representations in perceptual and motor regions. This approach predicts that concrete semantic features should activate both codes, whereas abstract features rely exclusively on the linguistic code. Using magnetoencephalography (MEG), we adopted a temporally resolved multiple regression approach to identify the contribution of abstract and concrete semantic predictors to the underlying brain signal. Results evidenced early involvement of anterior-temporal and inferior-frontal brain areas in both abstract and concrete semantic information encoding. At later stages, occipito-temporal regions showed greater responses to concrete compared to abstract features. The present findings shed new light on the temporal dynamics of abstract and concrete semantic representations in the brain and suggest that the concreteness of words processed first with a transmodal/linguistic code, housed in frontotemporal brain systems, and only after with an imagistic/sensorimotor code in perceptual and motor regions.

neuroscience↗

bioRxiv2023

Altered grid-like coding in early blind people

Spatial navigation in humans relies heavily on vision. However, the impact of early blindness on the brain navigation network and on the hippocampal-entorhinal system supporting cognitive maps, in particular, remains elusive. Here, we tested sighted and early blind individuals in both imagined navigation in fMRI and real-world navigation. During imagined navigation, the Human Navigation Network was reliably activated in both groups, showing resilience to visual deprivation. However, neural geometry analyses highlighted crucial differences between groups. A 60{degrees} rotational symmetry, characteristic of grid-like coding, emerged in the entorhinal cortex of sighted but not blind people, who instead showed a 4-fold (90{degrees}) symmetry. Moreover, higher parietal cortex activity during navigation in the blind was correlated with the magnitude of 4-fold symmetry and real-word navigation abilities. In sum, early blindness can alter the geometry of entorhinal cognitive maps, possibly as a consequence of higher reliance on parietal egocentric coding during navigation.

neuroscience↗

bioRxiv2023

Disentangling reference frames in the neural compass.

The neural system that encodes heading direction in humans is found consistently in the medial and superior parietal cortex and the entorhinal-retrosplenial circuit. However, it is still unclear whether heading direction in these different regions is represented within an allocentric or egocentric coordinate system. To investigate this problem, we first asked whether regions encoding (putatively) allocentric facing direction also encode (unambiguously) egocentric goal direction. Second, we assessed whether directional coding in these regions scaled with the preference for an allocentric perspective during everyday navigation. Before the experiment, participants learned different object maps in two geometrically similar rooms. In the MRI scanner, their task was to retrieve the egocentric position of a target object (e.g., Front, Left) relative to an imagined facing direction (e.g., North, West). Multivariate analyses showed, as predicted, that facing direction was encoded bilaterally in the superior parietal lobule (SPL), the retrosplenial complex (RSC), and the left entorhinal cortex (EC). Crucially, we found that the same voxels in the SPL and RSC also coded for egocentric goal direction. Moreover, when facing directions were expressed as egocentric bearings relative to a reference vector, activities for facing direction and egocentric direction were correlated, suggesting a common reference frame. Besides, only the left EC coded allocentric goal direction as a function of the subjects propensity to use allocentric strategies. Altogether, these results suggest that heading direction in the superior and medial parietal cortex is mediated by an egocentric code, whereas the entorhinal cortex encodes directions according to an allocentric reference frame.

neuroscience↗

bioRxiv2023

MEG frequency tagging reveals a grid-like code during covert attentional movements

Grid cells in the entorhinal cortex map regular environments with a 60{degrees} periodicity, encoding body- and eye-movements direction during spatial exploration. Recent evidence in monkeys suggests that grid cells firing is elicited by spatial attention even without eye movements. We investigated whether movements of covert attention can elicit grid-like responses in humans by concurrently recording MEG and eye-tracker. To obtain a measure of grid-like signal non-invasively, we developed a new paradigm based on frequency tagging. While keeping central fixation, participants were presented visually with sequences of linearly-spaced trajectories (15{degrees} or 30{degrees} in different conditions) formed by static lines or moving dots in separate sessions. Trajectories appeared sequentially on the screen at a fixed rate (6 Hz), allowing different spatial periodicities (e.g., 90{degrees}, 60{degrees}, 45{degrees}) to have corresponding temporal periodicities (e.g., 1, 1.5, 2 Hz), thus resulting in distinct spectral responses in the MEG signal. Analyses of inter-trial coherence evidenced a higher steady-state response for the frequency corresponding to 60{degrees} periodicity compared to control periodicities. This effect was localized in medial-temporal sources and not in control regions. Moreover, in a control experiment using a recurrent sequence of letters featuring the same temporal periodicity but lacking spatial structure, the 60{degrees} effect did not emerge, suggesting its dependency on spatial movements of attention. We report the first evidence, in humans, that grid-like signals in the medial-temporal lobe can be elicited by covert attentional movements. Moreover, we propose a new neuroimaging paradigm based on frequency tagging to study grid-like activity non-invasively.

neuroscience↗

bioRxiv2023

Mental search of concepts is supported by egocentric vector representations and restructured grid maps

The human hippocampal-entorhinal system is known to represent both spatial locations and abstract concepts in memory in the form of allocentric cognitive maps. Using fMRI, we show that the human parietal cortex evokes complementary egocentric-like vector representations in conceptual spaces during goal-directed mental search, akin to those observable during physical navigation to determine where a goal is located relative to oneself. Concurrently, grid-like representations, a neural signature of allocentric cognitive maps in entorhinal, prefrontal, and parietal cortices, are restructured as a function of conceptual goal proximity, akin to rodent grid cells firing around reward locations during spatial exploration. These brain mechanisms might support flexible and parallel readout of where target conceptual information is stored in memory, capitalizing on complementary reference frames.

neuroscience↗

bioRxiv2022

Supramodal Shape Representation in the Human Brain

We can sense an objects shape by vision or touch. Previous studies suggested that the inferolateral occipitotemporal cortex (ILOTC) implements supramodal shape representations as it responds more to seeing or touching objects than shapeless textures. However, such activation in the anterior portion of the ventral visual pathway could be due to the conceptual representation of an object or visual imagery triggered by touching an object. We addressed these possibilities by directly comparing shape and conceptual representations in early blind (who lack visual experience/imagery) and sighted participants. We found that bilateral ILOTC in both groups showed stronger activation during a shape verification task than during a conceptual verification task made on the names of the same manmade objects. Moreover, the distributed activity in the ILOTC encoded shape similarity but not conceptual association among objects. Besides the ILOTC, we also found shape representation in both groups bilateral ventral premotor cortices and intraparietal sulcus, a frontoparietal circuit relating to object grasping and haptic processing. In contrast, the conceptual verification task activated both groups left perisylvian brain network relating to language processing, and, interestingly, the cuneus in early blind participants only. The ILOTC had stronger functional connectivity to frontoparietal circuit than to the left perisylvian network, forming a modular structure specialized in shape representation. Our results conclusively support that the ILOTC selectively implements shape representation independently of visual experience, and this unique functionality likely comes from its privileged connection to the frontoparietal haptic circuit.

neuroscience↗

bioRxiv2021

Structural and functional network-level reorganization in the coding of auditory motion directions and sound source locations in the absence of vision

hMT+/V5 is a region in the middle occipito-temporal cortex that responds preferentially to visual motion in sighted people. In case of early visual deprivation, hMT+/V5 enhances its response to moving sounds. Whether hMT+/V5 contains information about motion directions and whether the functional enhancement observed in the blind is motion specific, or also involves sound source location, remains unsolved. Moreover, the impact of this crossmodal reorganization of hMT+/V5 on the regions typically supporting auditory motion processing, like the human Planum Temporale (hPT), remains equivocal. We used a combined functional and diffusion MRI approach and individual in-ear recordings to study the impact of early blindness on the brain networks supporting spatial hearing, in male and female humans. Whole-brain univariate analysis revealed that the anterior portion of hMT+/V5 responded to moving sounds in sighted and blind people, while the posterior portion was selective to moving sounds only in blind participants. Multivariate decoding analysis revealed that the presence of motion directions and sound positions information was higher in hMT+/V5 and lower in hPT in the blind group. While both groups showed axis-of-motion organization in hMT+/V5 and hPT, this organization was reduced in the hPT of blind people. Diffusion MRI revealed that the strength of hMT+/V5 - hPT connectivity did not differ between groups, whereas the microstructure of the connections was altered by blindness. Our results suggest that the axis-of-motion organization of hMT+/V5 does not depend on visual experience, but that blindness alters the response properties of occipito-temporal networks supporting spatial hearing in the sighted. Significance StatementSpatial hearing helps living organisms navigate their environment. This is certainly even more true in people born blind. How does blindness affect the brain network supporting auditory motion and sound source location? Our results show that the presence of motion directions and sound positions information was higher in hMT+/V5 and lower in hPT in blind relative to sighted people; and that this functional reorganization is accompanied by microstructural (but not macrostructural) alterations in their connections. These findings suggest that blindness alters crossmodal responses between connected areas that share the same computational goals.

neuroscience↗

bioRxiv2020

Brain Network Reconfiguration for Narrative and Argumentative Thought

Our brain constructs reality through narrative and argumentative thought. Some hypotheses argue that these two modes of cognitive functioning are irreducible, reflecting distinct mental operations underlain by separate neural bases; Others ascribe both to a unitary neural system dedicated to long-timescale information. We addressed this question by employing inter-subject measures to investigate the stimulus-induced neural responses when participants were listening to narrative and argumentative texts during fMRI. We found that following both kinds of texts enhanced functional couplings within the frontoparietal control system. However, while a narrative specifically implicated the default mode system, an argument specifically induced synchronization between the intraparietal sulcus in the frontoparietal control system and multiple perisylvian areas in the language system. Our findings reconcile the two hypotheses by revealing commonalities and differences between the narrative and the argumentative brain networks, showing how diverse mental activities arise from the segregation and integration of the existing brain systems.

neuroscience↗

bioRxiv2020

Timecourse and convergence of abstract and concrete knowledge in the anterior temporal lobe.

How is conceptual knowledge organized and retrieved by the brain? Recent evidence points to the anterior temporal lobe (ATL) as a crucial semantic hub integrating both abstract and concrete conceptual features according to a dorsal-to-medial gradient. It is however unclear when this conceptual gradient emerges and how semantic information reaches the ATL during conceptual retrieval. Here we used a multiple regression approach to magnetoencephalography signals of spoken words, combined with dimensionality reduction in concrete and abstract semantic feature spaces. Results showed that the dorsal-to-medial abstract-to-concrete ATL gradient emerges only in late stages of word processing: Abstract and concrete semantic information are initially encoded in posterior temporal regions and travel along separate cortical pathways eventually converging in the ATL. The present finding sheds light on the neural dynamics of conceptual processing that shape the organization of knowledge in the anterior temporal lobe.

neuroscience↗

bioRxiv2019

Similar categorical representation from sound and sight in the occipito-temporal cortex of sighted and blind

Is vision necessary for the development of the categorical organization of the Ventral Occipito-Temporal Cortex (VOTC)? We used fMRI to characterize VOTC responses to eight categories presented acoustically in sighted and early blind individuals, and visually in a separate sighted group. We observed that VOTC reliably encodes sound categories in sighted and blind people using a representational structure and connectivity partially similar to the one found in vision. Sound categories were, however, more reliably encoded in the blind than the sighted group, using a representational format closer to the one found in vision. Crucially, VOTC in blind represents the categorical membership of sounds rather than their acoustic features. Our results suggest that sounds trigger categorical responses in the VOTC of congenitally blind and sighted people that partially match the topography and functional profile of the visual response, despite qualitative nuances in the categorical organization of VOTC between modalities and groups.

neuroscience↗

bioRxiv2018

Different neural networks for conceptual retrieval in sighted and blind reveal the experiential bases of knowledge.

We investigated the experiential bases of knowledge by asking whether people that perceive the world in a different way also show a different neurobiology of concepts. We characterized the brain activity of early-blind and sighted individuals during a conceptual retrieval task in which participants rated the perceptual similarity between color and action concepts evoked by spoken words. Adaptation analysis showed that word-pairs referring to perceptually similar colors (e.g., red-orange) or actions (e.g., run-jump) led to repetition-suppression in occipital visual regions in the sighted, regions that are known to encode visual features of objects and events, independently of their category. Early blind showed instead adaptation for similar concepts in language-related regions, but not in occipital cortices. Further analysis contrasting the two categories (color and action), independently of item similarity, activated category-sensitive regions in the pMTG (for actions) and the precuneus (for color) in both sighted and blind. These two regions, however, showed a different connectivity profile as a function of visual deprivation, increasing task-dependent connectivity with reorganized occipital regions in the early blind. Overall, our results show that visual deprivation changes the neural bases of conceptual retrieval, which is partially grounded in sensorimotor experience.\n\nSignificance StatementDo people with different sensory experience conceive the world differently? We tested whether conceptual knowledge builds on sensory experience by looking at the neurobiology of concepts in early blind individuals. Participants in fMRI heard pairs of words referring to colors (e.g., green-blue) or actions (e.g., jump-run) and rated their perceptual similarity. Perceptual similarity of colors and actions was represented in occipital visual regions in the sighted, but in language-related regions in the blind. Occipital regions in the blind, albeit not encoding perceptual similarity, were however recruited during conceptual retrieval, working in concert with classic semantic hubs such as the Precuneus and the lpMTG. Overall, visual deprivation changes the neural bases of conceptual processing, which is partially grounded in sensorimotor experience.

neuroscience↗