Biology subjects

Sereno, M. I.

Publications and source records attributed to Sereno, M. I..

15 recordsLinked to original sources

bioRxiv2026

Tonotopic mapping in children shows an overrepresentation of high frequencies in autism

Altered sensitivity to sounds despite normal peripheral hearing is common in neurodevelopmental disorders but the underlying mechanisms remain poorly understood. Here we investigate tonotopic organization in 86 children (6-11 years) with autism spectrum and related neurodevelopmental disorders as well as typically developing (TD) peers, using a child-friendly, passive listening, functional magnetic resonance imaging design. In TD children, tonotopic maps in primary auditory cortex resembled the typical high-low-high frequency gradients previously reported in adults, while children with autism showed an overrepresentation of high frequencies consistent with what has been observed in animal models of autism. Higher frequency tuning further correlated with greater caregiver-reported sound but not touch sensitivities. Importantly, tonotopy is a core organizational feature of auditory cortex that develops early in life and remains relatively stable after the critical period of heightened plasticity ends. Thus, these results suggest that atypical auditory processing in autism may result from early disruption to tonotopic map formation. Longitudinal neuroimaging studies are needed to understand the genetic and environmental causes of altered auditory cortex topology and its long-term consequences for higher-level auditory, language, and social communication development.

neuroscience↗

bioRxiv2026

Time-resolved hemodynamic responses to sentence-level speech perception, production, and self-monitoring

Functional magnetic resonance imaging (fMRI) has been widely utilized to explore the neural mechanisms underlying speech processing. However, the intertwining of perception and production that exists in real-world scenarios remains underexplored due to challenges such as gradient noise and head motion artifacts from speaking. Previous research has often employed sparse-sampling designs, pausing image acquisition intermittently to present auditory stimuli or record overt speech. While this approach mitigates some challenges, it cannot capture continuous brain activity during speech processing and does not separate the mixed hemodynamic responses to external and self-generated speech occurring in succession. We overcame these limitations and continuously scanned thirty-one participants as they listened to and recited English sentences. Through independent component analysis (ICA), we decomposed each functional scan into spatially independent components (ICs), identifying task-related ICs in the superior temporal cortex, inferior frontal gyrus, and orofacial sensorimotor cortex. These ICs demonstrated time-resolved hemodynamic responses corresponding to distinct stages of speech perception, planning, and production. A linear subtraction between the IC time courses from the listening-reciting (perception-to-production) and listening (perception-only) tasks further revealed a secondary hemodynamic response to self-generated speech in the superior temporal cortex. Furthermore, we established precise temporal relationships between overt speech output and the peak, rise, and fall of hemodynamic responses for each independent component. Together, we present a methodological framework that can inform future fMRI studies on naturalistic tasks involving the perception of external auditory stimuli and monitoring of self-generated sounds.

neuroscience↗

bioRxiv2026

Tracking bilingual brain processing at high spatiotemporal resolution reveals where and when second language slows down

A central question in bilingualism research is whether challenges in a second language (L2) reflect a fundamentally different processing route from the first language (L1), or slower processing at particular stages. Although functional magnetic resonance imaging (fMRI) revealed substantial cortical overlap between L1 and L2, different processing mechanisms may interleave within the overlap. Conventional fMRI methods lack the combined spatial and temporal resolution needed to determine precisely where and when L1 and L2 dissociations occur. Here, we used rapid phase-encoded fMRI to track L1 and L2 processing within overlapping cortical regions. Thirty-one Chinese-English bilinguals completed sentence-level reading, listening, reading-aloud, and shadowing tasks in both Chinese (L1) and English (L2). By analyzing hemodynamic traveling waves along sample paths through the visual, auditory, and motor systems, we identified temporal dissociations between L1 and L2 processing. Compared with L1, L2 exhibited significant and consistent delays along dorsal and ventral visual streams during reading and reading aloud. Along auditory streams, L2 delays differed between externally presented speech (listening) and self-generated speech (reading aloud). In the frontal cortex, reading aloud and shadowing exhibited similar progression patterns, but with different temporal offsets between L1 and L2 in the dorsal and ventral motor streams. These findings reveal task- and modality-dependent differences between L1 and L2 processing, and pinpoint the exact locations for delayed L2 processing across multimodal streams. This study suggests that L2 disadvantage is often a matter of timing and efficiency within largely shared brain networks, rather than due to the use of different brain regions. Significant StatementRapid phase-encoded fMRI introduces a temporal dimension for comparing L1 and L2 processing, tracking the precise timing of neural information flow across the brain. Moving beyond functional localization, we directly visualize and quantify the propagation of hemodynamic traveling waves along selected paths in visual, auditory, and motor systems. Our ability to characterize temporal delays along specific functional streams represents an advancement in understanding dynamic cognitive processes beyond language. The findings can influence theories of language acquisition and cognitive processing in bilingual individuals. The methods to pinpoint locations where delays occur can be applied to other areas of cognitive neuroscience, allowing the exploration of complex neural interaction in real time across sensory, motor, and cognitive domains.

neuroscience↗

bioRxiv2025

Neural ensembles for music production recruit more language instruments as rhythmic complexity increases

Language and music, two core forms of human communication, both rely on rhythmic control. To date, the neural ensembles supporting their real-time production are not fully characterized. Using rapid phase-encoded fMRI, we mapped the spatiotemporal brain dynamics of overt language and music production under varying rhythm control demands. We observed overlapping hemodynamic traveling waves across domains, with auditory-motor regions activated earlier, followed by visual, posterior parietal, and Sylvian parietal-temporal (Spt) regions, supporting sensorimotor transformation and online monitoring of production. Increasing rhythmic complexity elicited slower and stronger activations in both domains: compared with baseline, regular rhythm control elicited delayed and amplified responses, while irregular rhythm control produced the slowest and strongest responses. During music production, rhythm-related activity expanded into frontal and temporal language regions, suggesting that higher rhythmic demands engage language resources. These findings reveal dynamic neural ensembles that can flexibly reconfigure shared resources to support temporal precision in sequence production.

neuroscience↗

bioRxiv2025

Phasor diagrams clock oscillatory hemodynamic switching between overt speech production and micro resting states

This study investigates the intricate interplay between the task-positive network and the default mode network (DMN) during transitions between overt language tasks and brief resting periods. While previous research suggests that these networks are not invariably anticorrelated, the precise timing of transitions has remained elusive. We employed rapid phase-encoded fMRI to decode brain dynamics with ultimate precision, capturing these transitions in real time. By utilizing phasor diagrams to represent the oscillatory activities, we examined the amplitudes and phases of hemodynamic fluctuations within the language network and DMN. Our findings align with existing empirical and theoretical perspectives on DMN functions and cognitive task performance, affirming the validity of our approach. We identified heterogeneous micro resting states interwoven with periods of overt speech production. Notably, various core regions of the DMN exhibited task-dependent amplitude and phase modulations, with activation strength and delay rising in line with increasing task complexity, ranging from comprehension to immediate and delayed speech production. This study sheds light on the dynamic engagement of the DMN during overt speech production, providing precise timing data of transitions between the DMN and language network. It demonstrates that rapid phase-encoded fMRI and phasor diagrams are powerful tools for measuring the switching between active tasks and micro resting states with subsecond accuracy, while also elucidating task load-dependent changes in the DMN. By accurately measuring the timing of these transitions, we gain insights into cognitive flexibility, attention, and the efficiency of information processing.

neuroscience↗

bioRxiv2025

Spatial specificity of the functional gradient echo and spin echo BOLD signal across cortical depth at 7 T

Functional magnetic resonance imaging (fMRI) at high magnetic field strengths ([≥] 7 T) is a promising technique to study the functioning of the human brain at the spatial scale of cortical columns and layers. However, measurements most often rely on the blood oxygenation level dependent (BOLD) response sampled with a gradient echo (GE) sequence, which is known to be most sensitive to macrovascular contributions that limit their effective spatial resolution. Alternatively, a spin echo (SE) sequence can be used to increase the weighting toward the microvasculature and, therefore, the location of neural activation. In addition, due to the heterogeneous structure of the cortical cerebrovascular system, the effective spatial resolution can change across cortical depth. For high-resolution fMRI applications, it is hence important to know how much the effective spatial resolution varies across cortical depth. In this study, we used flickering rotating wedge stimuli to induce traveling waves with varying spatial frequencies in the retinotopically organized primary visual cortex (V1), which allowed us to infer the modulation transfer function (MTF) of the BOLD response that characterizes the spatial specificity of the measured signal. We acquired GE- and SE-BOLD data at 7 T and compared the MTF between acquisition techniques at different cortical depths. Our results show a small but consistent increase in spatial specificity when using SE-BOLD. But across cortical depth, both acquisition techniques generally show a similar decrease of specificity toward the pial surface demonstrating the dependence on macrovascular contributions, which needs to be carefully considered when interpreting the results of high-resolution fMRI studies.

neuroscience↗

bioRxiv2023

Phase-encoded fMRI tracks down brainstorms of natural language processing with sub-second precision

The human language system interacts with cognitive and sensorimotor regions during natural language processing. However, where, when, and how these processes occur remain unclear. Existing noninvasive subtraction-based neuroimaging techniques cannot simultaneously achieve the spatial and temporal resolutions required to visualize ongoing information flows across the whole brain. Here we have developed phase-encoded designs to fully exploit the temporal information latent in functional magnetic resonance imaging (fMRI) data, as well as overcoming scanner noise and head-motion challenges during overt language tasks. We captured neural information flows as coherent waves traveling over the cortical surface during listening, reciting, and oral cross-language interpreting. The timing, location, direction, and surge of traveling waves, visualized as brainstorms on brain weather maps, reveal the functional and effective connectivity of the brain in action. These maps uncover the functional neuroanatomy of language perception and production and motivate the construction of finer-grained models of human information processing.

neuroscience↗

bioRxiv2022

High resolution quantitative and functional MRI indicate lower myelination of thin and thick stripes in human secondary visual cortex

The characterization of cortical myelination is essential for the study of structure-function relationships in the human brain. However, knowledge about cortical myelination is largely based on post mortem histology, which generally renders direct comparison to function impossible. The repeating pattern of pale-thin-pale-thick stripes of cytochrome oxidase (CO) activity in the primate secondary visual cortex (V2) is a prominent columnar system, in which histology also indicates different myelination of thin/thick versus pale stripes. We used quantitative magnetic resonance imaging (qMRI) in conjunction with functional magnetic resonance imaging (fMRI) at ultra-high field strength (7 T) to localize and study myelination of stripes in four human participants at sub-millimeter resolution in vivo. Thin and thick stripes were functionally localized by exploiting their sensitivity to color and binocular disparity, respectively. Resulting functional activation maps showed robust stripe patterns in V2 which enabled further comparison of quantitative relaxation parameters between stripe types. Thereby, we found lower longitudinal relaxation rates (R1) of thin and thick stripes compared to surrounding gray matter in the order of 1-2%, indicating higher myelination of pale stripes. No consistent differences were found for effective transverse relaxation rates [Formula]. The study demonstrates the feasibility to investigate structure-function relationships in living humans within one cortical area at the level of columnar systems using qMRI.

neuroscience↗

bioRxiv2019

Altered visual population receptive fields in human albinism

1Albinism is a congenital disorder where misrouting of the optic nerves at the chiasm gives rise to abnormal visual field representations in occipital cortex. In typical human development, the left occipital cortex receives retinal input predominantly from the right visual field, and vice-versa. In albinism, there is a more complete decussation of optic nerve fibers at the chiasm, resulting in partial representation of the temporal hemiretina (ipsilateral visual field) in the contralateral hemisphere. In this study, we characterize the receptive field properties for these abnormal representations by conducting detailed fMRI population receptive field mapping in a rare subset of participants with albinism and no ocular nystagmus. We find a nasal bias for receptive field positions in the abnormal temporal hemiretina representation. In addition, by modelling responses to bilateral visual field stimulation in the overlap zone, we found evidence in favor of discrete unilateral receptive fields, suggesting a conservative pattern of spatial selectivity in the presence of abnormal retinal input. HighlightsO_LIWe characterized population receptive fields in albinotic participants with no ocular nystagmus C_LIO_LIConfirmed overlapping representations of left and right visual fields in cortex C_LIO_LIDetected nasal bias in receptive field location for temporal hemiretina representation C_LIO_LIEvidence in favor of discrete unilateral receptive fields and against double coding C_LI

neuroscience↗

bioRxiv2019

Reconstructing neural representations of tactile space

Psychophysical experiments have demonstrated large and highly systematic perceptual distortions of tactile space. We investigated the neural basis of tactile space by analyzing activity patterns induced by tactile stimulation of nine points on a 3 x 3 square grid on the hand dorsum using functional magnetic resonance (fMRI). We used a searchlight approach within pre-defined regions of interests (ROIs) to compute the pairwise Euclidean distances between the activity patterns elicited by tactile stimulation. Then, we used multidimensional scaling (MDS) to reconstruct tactile space at the neural level and compare it with skin space at the perceptual level. Our reconstructions of the shape of skin space in contralateral primary somatosensory (SI) and motor (M1) cortices reveal that it is distorted in a way that matches the perceptual shape of skin space. This suggests that early sensorimotor areas are critical to processing tactile space perception.\n\nSignificant StatementHere, we show that the primary somatosensory (SI) and motor (M1) cortices, rather than higher-level brain areas, are critical to estimating distances between tactile stimuli on the hand dorsum. By combining functional magnetic resonance (fMRI), Procrustes alignment, and multidimensional scaling, we reconstructed the shape of skin space in the brain. Strikingly, the shape of the skin that we reconstructed from neural data matches the distortions we found at the behavioral level, providing strong evidence that early sensorimotor areas are critical for the construction of tactile space. Our work therefore supports the view that tactile distance perception is computed at lower level in the somatosensory system than is usually supposed.

neuroscience↗

bioRxiv2019

Within-finger maps of tactile and nociceptive input in the human parietal cortex

The spatial representation of nociceptive input in the human parietal cortex is not fully understood. For instance, it is known that the primary somatosensory cortex (S1) contains a representation of nociceptive-selective input to different fingers, but it is unclear whether S1 subdivisions contain finer-grained, within-finger maps of nociceptive input. It is also unknown whether within-finger maps of somatosensory input exist in intraparietal regions. Therefore, we used high-field 7T functional MRI to reveal within-finger maps of nociceptive and tactile inputs in the human parietal cortex. Although we replicated the previous findings of between-finger maps of nociceptive input spanning S1 subdivisions, we found weak and inconsistent evidence for within-finger maps of nociceptive input in S1 subdivisions. In the same subjects, we found mirrored, within-finger maps of tactile input in areas 3a, 3b, and 1. Importantly, we discovered a within-finger map of nociceptive input, but not of tactile input, in the human intraparietal area 1 (hIP1). In conclusion, our study indicates that the spatial representation of nociceptive input in the parietal cortex partly differs from that of tactile input and reports the discovery of a within-finger map of nociceptive input in hIP1.\n\nNew & NoteworthyWe report the discovery of a fine-grained map of nociceptive input to finger segments in the human intraparietal area 1.

neuroscience↗

bioRxiv2018

Preserved cortical maps of the body in Complex Regional Pain Syndrome

Chronic pain can be associated with functional and morphological changes in the brain. It has long been thought that some severe chronic pain conditions, such as Complex Regional Pain Syndrome (CRPS), are not only associated with, but even maintained by a reorganisation of the somatotopic representation of the affected limb in the primary somatosensory cortex (S1). This notion has driven treatments that aim to restore S1 representations, such as sensory discrimination training and mirror therapy. However, this notion is based on both indirect and incomplete evidence obtained with imaging methods with low spatial resolution. Here, we used functional MRI to characterize the S1 representation of the affected and unaffected hand in patients with unilateral CRPS of one hand. Our study demonstrates that the cortical area, location, and geometry of the S1 representation of the CRPS hand are comparable to those of the healthy hand, as well as to those of controls. Given that S1 representations are largely preserved in CPRS patients, it is compelling to reconsider not only the cortical mechanisms that underlie the disorder, but also the rationale for interventions that aim to \"restore\" somatotopic representations.

neuroscience↗

bioRxiv2018

Estimating the cortex-wide overlap between wordless narrative scene comprehension, reading comprehension, and topological visual, auditory, and somatomotor maps

Previous imaging research in scene comprehension has mostly focussed on isolated scenes and objects. Here we use narrative picture stimuli and a novel controlled presentation technique to identify the full extent of activation during naturalistic narrative scene comprehension. We then situate it with respect to topologically-mapped sensory and motor regions as well as cortical regions activated during naturalistic narrative reading comprehension. The data for all experiments was obtained from the same set of subjects, and analyzed using cortical surface based methods from start to finish. The results suggest that scene and reading activations are spread across occipital, parietal, temporal, and frontal cortex, and largely aligned with each other. Within these regions, there were also sites uniquely activated when subjects were engaged in either narrative scene comprehension or in reading comprehension. Finally, the cortical activations for both scene and reading comprehension contrasts substantially overlap topological cortical maps, specifically retinotopic and tonotopic maps in occipital, parietal, temporal, and frontal cortex.

neuroscience↗

bioRxiv2017

Population receptive field tuning properties of visual cortex during childhood

Improvements in visuospatial perception such as contrast sensitivity and Vernier acuity continue until late in childhood, but the neural mechanisms driving these age-related changes are currently unclear. One contributing factor could be the protracted development of spatial tuning of neuronal populations across the visual cortex. Here we tested this possibility using population receptive field (pRF) mapping (Dumoulin and Wandell, 2008) in 6-to 12-year-old children and adults. We fitted pRF models to BOLD signals measured in areas V1-V4 and V3a during fMRI whilst participants watched wedge and ring stimuli traversing the visual field. Cortical magnification and the width of pRF tuning functions changed with viewing eccentricity in all participants. However, there were no age-related changes in pRF size, shape, cortical magnification, or map consistency across any of the visual areas measured. These results suggest that visuospatial perception in late childhood beyond age 6 years is not substantially limited by low-level spatial tuning properties of neuronal populations in visual cortex. Instead, performance improvements in this period may reflect more efficient use of the spatial information available in the visual system when forming perceptual judgments. These findings are an important step towards disentangling which neural mechanisms contribute to the eventual emergence of mature spatial vision, and for understanding the processes that determine the scope for visual plasticity at different stages of life.

neuroscience↗

bioRxiv2017

Extensive Tonotopic Mapping Across Auditory Cortex Is Recapitulated By Spectrally-Directed Attention, And Systematically Related To Cortical Myeloarchitecture

Auditory selective attention is vital in natural soundscapes. But, it is unclear how attentional focus on the primary dimension of auditory representation - acoustic frequency - might modulate basic auditory functional topography during active listening. In contrast to visual selective attention, which is supported by motor-mediated optimization of input across saccades and pupil dilation, the primate auditory system has fewer means of differentially sampling the world. This makes spectrally-directed endogenous attention a particularly crucial aspect of auditory attention. Using a novel functional paradigm combined with quantitative MRI, we establish that human frequency-band-selective attention drives activation in both myeloarchitectonically-estimated auditory core, and across the majority of tonotopically-mapped non-primary auditory cortex. The attentionally-driven best-frequency maps show strong concordance with sensory-driven maps in the same subjects across much of the temporal plane, with poor concordance in non-auditory areas. There is significantly greater activation across most of auditory cortex when best frequency is attended, versus ignored. Moreover, the single frequency bands that evoke the least activation and the frequency bands that elicit the least activation when attention is directed to them also correspond closely. Finally, the results demonstrate that there is spatial correspondence between the degree of myelination and the strength of the tonotopic signal across a number of regions in auditory cortex. Strong frequency preferences across tonotopically-mapped auditory cortex spatially correlate with R1-estimated myeloarchitecture, indicating shared functional and anatomical organization that may underlie intrinsic auditory regionalization.\n\nSignificancePerception is an active process especially sensitive to attentional state. Listeners direct auditory attention to track a violins melody within an ensemble performance, or to follow a voice in a crowded cafe. Although diverse pathologies reduce quality of life by impacting such spectrally-directed auditory attention, its neurobiological bases are unclear. We demonstrate that human primary and non-primary auditory cortical activation is modulated by spectrally-directed attention in a manner that recapitulates its tonotopic sensory organization. Further, the graded activation profiles evoked by single frequency bands are correlated with attentionally-driven activation when these bands are presented in complex soundscapes. Finally, we observe a strong concordance in the degree of cortical myelination and the strength of tonotopic activation across several auditory cortical regions.

neuroscience↗