Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
1.
Int J Pediatr Otorhinolaryngol ; 181: 111927, 2024 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-38723425

RESUMO

PURPOSE: This work presents a new frame-by-frame video analysis method called Child-Caregiver Communication Assessment through Rebesco's Evaluation (CC-CARE), developed in the context of pediatric hearing loss as a rehabilitation tool for assessing children's early communication skills. CC-CARE stems from the commonly used Tait video analysis and extends it by including a new set of parameters aimed at disentangling between hearing-dependent and hearing-independent aspects of communication. METHOD: In this paper, we collected video samples of child-caregiver interactions in a group of 65 normal-hearing children and a group of 165 hearing-impaired children. For each group, we present the CC-CARE method and describe the parameters, their score distributions, correlations and we estimate the adherence of the CC-CARE scores with children's developmental trajectory. Moreover, we compare the results of CC-CARE scores between the two groups having had different development of the auditory system. Finally, a fully-data driven approach was employed to assess the consistency of the communicative efficacy index (CEI), a score aiming to capture a global result of the CC-CARE procedure. RESULTS: Correlations among parameter scores were found in each within-group analysis, revealing CC-CARE's internal consistency in measuring associated but nonoverlapping communication dimensions. For both groups, CC-CARE scores were associated with participants' age. Differences between scores emerged for a between-group analysis, indicating CC-CARE sensitivity to extract communication differences as a function of the hearing status. For both groups, the data analysis revealed that the CEI captures large variance portions across all parameter scores of the CC-CARE method. CONCLUSIONS: Results provide the first evidence that the CC-CARE video analysis method could be a reliable tool capable of highlighting the cascading effects of hearing impairment on children's preverbal communicative efficacy. The CC-CARE method aims to support early rehabilitation of hearing loss by describing a child's communicative efficacy.

2.
Sci Adv ; 10(10): eadk6840, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38457501

RESUMO

Emotion and perception are tightly intertwined, as affective experiences often arise from the appraisal of sensory information. Nonetheless, whether the brain encodes emotional instances using a sensory-specific code or in a more abstract manner is unclear. Here, we answer this question by measuring the association between emotion ratings collected during a unisensory or multisensory presentation of a full-length movie and brain activity recorded in typically developed, congenitally blind and congenitally deaf participants. Emotional instances are encoded in a vast network encompassing sensory, prefrontal, and temporal cortices. Within this network, the ventromedial prefrontal cortex stores a categorical representation of emotion independent of modality and previous sensory experience, and the posterior superior temporal cortex maps the valence dimension using an abstract code. Sensory experience more than modality affects how the brain organizes emotional information outside supramodal regions, suggesting the existence of a scaffold for the representation of emotional states where sensory inputs during development shape its functioning.


Assuntos
Encéfalo , Emoções , Humanos , Estimulação Luminosa , Córtex Pré-Frontal , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética
3.
Sleep Med ; 113: 357-369, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38113618

RESUMO

INTRODUCTION: Studies using scalp EEG have shown that slow waves (0.5-4 Hz), the most prominent hallmark of NREM sleep, undergo relevant changes from childhood to adulthood, mirroring brain structural modifications and the acquisition of cognitive skills. Here we used simultaneous EEG-fMRI to investigate the cortical and subcortical correlates of slow waves in school-age children and determine their relative developmental changes. METHODS: We analyzed data from 14 school-age children with self-limited focal epilepsy of childhood who fell asleep during EEG-fMRI recordings. Brain regions associated with slow-wave occurrence were identified using a voxel-wise regression that also modelled interictal epileptic discharges and sleep spindles. At the group level, a mixed-effects linear model was used. The results were qualitatively compared with those obtained from 2 adolescents with epilepsy and 17 healthy adults. RESULTS: Slow waves were associated with hemodynamic-signal decreases in bilateral somatomotor areas. Such changes extended more posteriorly relative to those in adults. Moreover, the involvement of areas belonging to the default mode network changes as a function of age. No significant hemodynamic responses were observed in subcortical structures. However, we identified a significant correlation between age and thalamic hemodynamic changes. CONCLUSIONS: Present findings indicate that the somatomotor cortex may have a key role in slow-wave expression throughout the lifespan. At the same time, they are consistent with a posterior-to-anterior shift in slow-wave distribution mirroring brain maturational changes. Finally, our results suggest that slow-wave changes may not reflect only neocortical modifications but also the maturation of subcortical structures, including the thalamus.


Assuntos
Epilepsia , Imageamento por Ressonância Magnética , Adulto , Criança , Adolescente , Humanos , Adulto Jovem , Imageamento por Ressonância Magnética/métodos , Sono/fisiologia , Eletroencefalografia/métodos , Tálamo , Encéfalo
4.
Affect Sci ; 4(4): 770-780, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38156253

RESUMO

A wealth of literature suggests the existence of sex differences in how emotions are experienced, recognized, expressed, and regulated. However, to what extent these differences result from the put in place of stereotypes and social rules is still a matter of debate. Literature is an essential cultural institution, a transposition of the social life of people but also of their intimate affective experiences, which can serve to address questions of psychological relevance. Here, we created a large corpus of literary fiction enriched by authors' metadata to measure the extent to which culture influences how men and women write about emotion. Our results show that even though before the twenty-first century and across 116 countries women more than men have written about affect, starting from 2000, this difference has diminished substantially. Also, in the past, women's narratives were more positively laden and less arousing. While the difference in arousal is ubiquitous and still present nowadays, sex differences in valence vary as a function of culture and have dissolved in recent years. Altogether, these findings suggest that historic evolution is associated with men and women writing similarly about emotions and reveal a sizable impact of culture on the affective characteristics of the lexicon. Supplementary Information: The online version contains supplementary material available at 10.1007/s42761-023-00219-9.

5.
Sci Rep ; 13(1): 8110, 2023 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-37208405

RESUMO

Narratives are paradigmatic examples of natural language, where nouns represent a proxy of information. Functional magnetic resonance imaging (fMRI) studies revealed the recruitment of temporal cortices during noun processing and the existence of a noun-specific network at rest. Yet, it is unclear whether, in narratives, changes in noun density influence the brain functional connectivity, so that the coupling between regions correlates with information load. We acquired fMRI activity in healthy individuals listening to a narrative with noun density changing over time and measured whole-network and node-specific degree and betweenness centrality. Network measures were correlated with information magnitude with a time-varying approach. Noun density correlated positively with the across-regions average number of connections and negatively with the average betweenness centrality, suggesting the pruning of peripheral connections as information decreased. Locally, the degree of the bilateral anterior superior temporal sulcus (aSTS) was positively associated with nouns. Importantly, aSTS connectivity cannot be explained by changes in other parts of speech (e.g., verbs) or syllable density. Our results indicate that the brain recalibrates its global connectivity as a function of the information conveyed by nouns in natural language. Also, using naturalistic stimulation and network metrics, we corroborate the role of aSTS in noun processing.


Assuntos
Mapeamento Encefálico , Encéfalo , Humanos , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Idioma , Lobo Temporal/fisiologia , Fala , Imageamento por Ressonância Magnética
6.
Nat Hum Behav ; 7(3): 397-410, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36646839

RESUMO

The processing of multisensory information is based upon the capacity of brain regions, such as the superior temporal cortex, to combine information across modalities. However, it is still unclear whether the representation of coherent auditory and visual events requires any prior audiovisual experience to develop and function. Here we measured brain synchronization during the presentation of an audiovisual, audio-only or video-only version of the same narrative in distinct groups of sensory-deprived (congenitally blind and deaf) and typically developed individuals. Intersubject correlation analysis revealed that the superior temporal cortex was synchronized across auditory and visual conditions, even in sensory-deprived individuals who lack any audiovisual experience. This synchronization was primarily mediated by low-level perceptual features, and relied on a similar modality-independent topographical organization of slow temporal dynamics. The human superior temporal cortex is naturally endowed with a functional scaffolding to yield a common representation across multisensory events.


Assuntos
Percepção Auditiva , Percepção Visual , Humanos , Estimulação Acústica , Lobo Temporal , Encéfalo
7.
Front Psychol ; 13: 798871, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35422741

RESUMO

Humans naturally perceive visual patterns in a global manner and are remarkably capable of extracting object shapes based on properties such as proximity, closure, symmetry, and good continuation. Notwithstanding the role of these properties in perceptual grouping, studies highlighted differences in disembedding performance across individuals, which are summarized by the field dependence dimension. Evidence suggests that age and educational attainment explain part of this variability, whereas the role of sex is still highly debated. Also, which stimulus features primarily influence inter-individual variations in perceptual grouping has still to be fully determined. Building upon these premises, we assessed the role of age, education level, and sex on performance at the Leuven Embedded Figure Test-a proxy of disembedding abilities-in 391 cisgender individuals. We also investigated to what extent shape symmetry, closure, complexity, and continuation relate to task accuracy. Overall, target asymmetry, closure, and good continuation with the embedding context increase task difficulty. Simpler shapes are more difficult to detect than those with more lines, yet context complexity impairs the recognition of complex targets (i.e., those with 6 lines or more) to a greater extent. Concerning demographic data, we confirm that age and educational attainment are significantly associated with disembedding abilities and reveal a perceptual advantage in males. In summary, our study further highlights the role of shape properties in disembedding performance and unveils sex differences not reported so far.

8.
Soc Cogn Affect Neurosci ; 17(5): 461-469, 2022 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-34673987

RESUMO

In everyday life, the stream of affect results from the interaction between past experiences, expectations and the unfolding of events. How the brain represents the relationship between time and affect has been hardly explored, as it requires modeling the complexity of everyday life in the laboratory setting. Movies condense into hours a multitude of emotional responses, synchronized across subjects and characterized by temporal dynamics alike real-world experiences. Here, we use time-varying intersubject brain synchronization and real-time behavioral reports to test whether connectivity dynamics track changes in affect during movie watching. The results show that polarity and intensity of experiences relate to the connectivity of the default mode and control networks and converge in the right temporoparietal cortex. We validate these results in two experiments including four independent samples, two movies and alternative analysis workflows. Finally, we reveal chronotopic connectivity maps within the temporoparietal and prefrontal cortex, where adjacent areas preferentially encode affect at specific timescales.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Córtex Cerebral/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Filmes Cinematográficos , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia
9.
Neuroimage ; 244: 118574, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34508897

RESUMO

Functional Quantitative Susceptibility Mapping (fQSM) allows for the quantitative measurement of time-varying magnetic susceptibility across cortical and subcortical brain structures with a potentially higher spatial specificity than conventional fMRI. While the usefulness of fQSM with General Linear Model and "On/Off" paradigms has been assessed, little is known about the potential applications and limitations of this technique in more sophisticated experimental paradigms and analyses, such as those currently used in modern neuroimaging. To thoroughly characterize fQSM activations, here we used 7T MRI, tonotopic mapping, as well as univariate (i.e., GLM and population Receptive Field) and multivariate (Representational Similarity Analysis; RSA) analyses. Although fQSM detected less tone-responsive voxels than fMRI, they were more consistently localized in gray matter. Also, the majority of active gray matter voxels exhibited negative fQSM response, signaling the expected oxyhemoglobin increase, whereas positive fQSM activations were mainly in white matter. Though fMRI- and fQSM-based tonotopic maps were overall comparable, the representation of frequency tunings in tone-sensitive regions was significantly more balanced for fQSM. Lastly, RSA revealed that frequency information from the auditory cortex could be successfully retrieved by using either methods. Overall, fQSM produces complementary results to conventional fMRI, as it captures small-scale variations in the activation pattern which inform multivariate measures. Although positive fQSM responses deserve further investigation, they do not impair the interpretation of contrasts of interest. The quantitative nature of fQSM, its spatial specificity and the possibility to simultaneously acquire canonical fMRI support the use of this technique for longitudinal and multicentric studies and pre-surgical mapping.


Assuntos
Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Adulto , Córtex Auditivo/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Meios de Contraste , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Modelos Lineares , Masculino , Substância Branca/diagnóstico por imagem
10.
Clocks Sleep ; 3(3): 495-514, 2021 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-34563057

RESUMO

The study of dreams represents a crucial intersection between philosophical, psychological, neuroscientific, and clinical interests. Importantly, one of the main sources of insight into dreaming activity are the (oral or written) reports provided by dreamers upon awakening from their sleep. Classically, two main types of information are commonly extracted from dream reports: structural and semantic, content-related information. Extracted structural information is typically limited to the simple count of words or sentences in a report. Instead, content analysis usually relies on quantitative scores assigned by two or more (blind) human operators through the use of predefined coding systems. Within this review, we will show that methods borrowed from the field of linguistic analysis, such as graph analysis, dictionary-based content analysis, and distributional semantics approaches, could be used to complement and, in many cases, replace classical measures and scales for the quantitative structural and semantic assessment of dream reports. Importantly, these methods allow the direct (operator-independent) extraction of quantitative information from language data, hence enabling a fully objective and reproducible analysis of conscious experiences occurring during human sleep. Most importantly, these approaches can be partially or fully automatized and may thus be easily applied to the analysis of large datasets.

11.
Gigascience ; 10(6)2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34143875

RESUMO

BACKGROUND: Shedding light on the neuroscientific mechanisms of human upper limb motor control, in both healthy and disease conditions (e.g., after a stroke), can help to devise effective tools for a quantitative evaluation of the impaired conditions, and to properly inform the rehabilitative process. Furthermore, the design and control of mechatronic devices can also benefit from such neuroscientific outcomes, with important implications for assistive and rehabilitation robotics and advanced human-machine interaction. To reach these goals, we believe that an exhaustive data collection on human behavior is a mandatory step. For this reason, we release U-Limb, a large, multi-modal, multi-center data collection on human upper limb movements, with the aim of fostering trans-disciplinary cross-fertilization. CONTRIBUTION: This collection of signals consists of data from 91 able-bodied and 65 post-stroke participants and is organized at 3 levels: (i) upper limb daily living activities, during which kinematic and physiological signals (electromyography, electro-encephalography, and electrocardiography) were recorded; (ii) force-kinematic behavior during precise manipulation tasks with a haptic device; and (iii) brain activity during hand control using functional magnetic resonance imaging.


Assuntos
Robótica , Reabilitação do Acidente Vascular Cerebral , Braço , Interface Háptica , Humanos , Extremidade Superior
12.
Neuroimage ; 236: 118117, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-33940148

RESUMO

EEG slow waves, the hallmarks of NREM sleep are thought to be crucial for the regulation of several important processes, including learning, sensory disconnection and the removal of brain metabolic wastes. Animal research indicates that slow waves may involve complex interactions within and between cortical and subcortical structures. Conventional EEG in humans, however, has a low spatial resolution and is unable to accurately describe changes in the activity of subcortical and deep cortical structures. To overcome these limitations, here we took advantage of simultaneous EEG-fMRI recordings to map cortical and subcortical hemodynamic (BOLD) fluctuations time-locked to slow waves of light sleep. Recordings were performed in twenty healthy adults during an afternoon nap. Slow waves were associated with BOLD-signal increases in the posterior brainstem and in portions of thalamus and cerebellum characterized by preferential functional connectivity with limbic and somatomotor areas, respectively. At the cortical level, significant BOLD-signal decreases were instead found in several areas, including insula and somatomotor cortex. Specifically, a slow signal increase preceded slow-wave onset and was followed by a delayed, stronger signal decrease. Similar hemodynamic changes were found to occur at different delays across most cortical brain areas, mirroring the propagation of electrophysiological slow waves, from centro-frontal to inferior temporo-occipital cortices. Finally, we found that the amplitude of electrophysiological slow waves was positively related to the magnitude and inversely related to the delay of cortical and subcortical BOLD-signal changes. These regional patterns of brain activity are consistent with theoretical accounts of the functions of sleep slow waves.


Assuntos
Tronco Encefálico/fisiologia , Ondas Encefálicas/fisiologia , Cerebelo/fisiologia , Acoplamento Neurovascular/fisiologia , Córtex Sensório-Motor/fisiologia , Sono de Ondas Lentas/fisiologia , Tálamo/fisiologia , Adulto , Tronco Encefálico/diagnóstico por imagem , Cerebelo/diagnóstico por imagem , Eletroencefalografia , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Sensório-Motor/diagnóstico por imagem , Tálamo/diagnóstico por imagem
13.
Eur J Neurosci ; 53(2): 357-361, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32852863

RESUMO

In neuroimaging studies, small sample sizes and the resultant reduced statistical power to detect effects that are not large, combined with inadequate analytic choices, concur to produce inflated or false-positive findings. To mitigate these issues, researchers often restrict analyses to specific brain areas, using the region of interest (ROI) approach. Crucially, ROI analysis assumes the a priori justified definition of the target region. Nonetheless, reports often lack details about where in the timeline, ranging from study conception to the data analysis and interpretation of findings, were ROIs selected. Frequently, the rationale for ROI selection is vague or inadequately founded on the existing literature. These shortcomings have important implications for ROI-based studies, augmenting the risk that observed effects are inflated or even false positives. Tools like preregistration and registered reports could address this problem, ensuring the validity of ROI-based studies. The benefits could be enhanced by additional practices such as selection of ROIs using quantitative methods (i.e., meta-analysis) and the sharing of whole-brain unthresholded maps of effect size, as well as of binary ROIs, in publicly accessible repositories.


Assuntos
Mapeamento Encefálico , Neuroimagem , Encéfalo/diagnóstico por imagem
14.
J Neurophysiol ; 124(6): 1560-1570, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33052726

RESUMO

Object recognition relies on different transformations of the retinal input, carried out by the visual system, that range from local contrast to object shape and category. While some of those transformations are thought to occur at specific stages of the visual hierarchy, the features they represent are correlated (e.g., object shape and identity) and selectivity for the same feature overlaps in many brain regions. This may be explained either by collinearity across representations or may instead reflect the coding of multiple dimensions by the same cortical population. Moreover, orthogonal and shared components may differently impact distinctive stages of the visual hierarchy. We recorded functional MRI activity while participants passively attended to object images and employed a statistical approach that partitioned orthogonal and shared object representations to reveal their relative impact on brain processing. Orthogonal shape representations (silhouette, curvature, and medial axis) independently explained distinct and overlapping clusters of selectivity in the occitotemporal and parietal cortex. Moreover, we show that the relevance of shared representations linearly increases moving from posterior to anterior regions. These results indicate that the visual cortex encodes shared relations between different features in a topographic fashion and that object shape is encoded along different dimensions, each representing orthogonal features.NEW & NOTEWORTHY There are several possible ways of characterizing the shape of an object. Which shape description better describes our brain responses while we passively perceive objects? Here, we employed three competing shape models to explain brain representations when viewing real objects. We found that object shape is encoded in a multidimensional fashion and thus defined by the interaction of multiple features.


Assuntos
Lobo Occipital/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Modelos Neurológicos , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Adulto Jovem
15.
J Neurosci ; 40(29): 5589-5603, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32541070

RESUMO

The slow waves of non-rapid eye movement (NREM) sleep reflect experience-dependent plasticity and play a direct role in the restorative functions of sleep. Importantly, slow waves behave as traveling waves, and their propagation is assumed to occur through cortico-cortical white matter connections. In this light, the corpus callosum (CC) may represent the main responsible for cross-hemispheric slow-wave propagation. To verify this hypothesis, we performed overnight high-density (hd)-EEG recordings in five patients who underwent total callosotomy due to drug-resistant epilepsy (CPs; two females), in three noncallosotomized neurologic patients (NPs; two females), and in a sample of 24 healthy adult subjects (HSs; 13 females). In all CPs slow waves displayed a significantly reduced probability of cross-hemispheric propagation and a stronger inter-hemispheric asymmetry. In both CPs and HSs, the incidence of large slow waves within individual NREM epochs tended to differ across hemispheres, with a relative overall predominance of the right over the left hemisphere. The absolute magnitude of this asymmetry was greater in CPs relative to HSs. However, the CC resection had no significant effects on the distribution of slow-wave origin probability across hemispheres. The present results indicate that CC integrity is essential for the cross-hemispheric traveling of slow waves in human sleep, which is in line with the assumption of a direct relationship between white matter integrity and slow-wave propagation. Our findings also revealed a residual cross-hemispheric slow-wave propagation that may rely on alternative pathways, including cortico-subcortico-cortical loops. Finally, these data indicate that the lack of the CC does not lead to differences in slow-wave generation across brain hemispheres.SIGNIFICANCE STATEMENT The slow waves of NREM sleep behave as traveling waves, and their propagation has been suggested to reflect the integrity of white matter cortico-cortical connections. To directly assess this hypothesis, here we investigated the role of the corpus callosum in the cortical spreading of NREM slow waves through the study of a rare population of totally callosotomized patients. Our results demonstrate a causal role of the corpus callosum in the cross-hemispheric traveling of sleep slow waves. Additionally, we found that callosotomy does not affect the relative tendency of each hemisphere at generating slow waves. Incidentally, we also found that slow waves tend to originate more often in the right than in the left hemisphere in both callosotomized and healthy adult individuals.


Assuntos
Ondas Encefálicas , Corpo Caloso/fisiologia , Sono de Ondas Lentas , Adulto , Idoso , Corpo Caloso/cirurgia , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Procedimento de Encéfalo Dividido
16.
Nat Commun ; 10(1): 5568, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31804504

RESUMO

Humans use emotions to decipher complex cascades of internal events. However, which mechanisms link descriptions of affective states to brain activity is unclear, with evidence supporting either local or distributed processing. A biologically favorable alternative is provided by the notion of gradient, which postulates the isomorphism between functional representations of stimulus features and cortical distance. Here, we use fMRI activity evoked by an emotionally charged movie and continuous ratings of the perceived emotion intensity to reveal the topographic organization of affective states. Results show that three orthogonal and spatially overlapping gradients encode the polarity, complexity and intensity of emotional experiences in right temporo-parietal territories. The spatial arrangement of these gradients allows the brain to map a variety of affective states within a single patch of cortex. As this organization resembles how sensory regions represent psychophysical properties (e.g., retinotopy), we propose emotionotopy as a principle of emotion coding.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Emoções , Lobo Parietal/fisiologia , Adulto , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Lobo Parietal/anatomia & histologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa/métodos , Adulto Jovem
17.
Neural Plast ; 2019: 6874805, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31281345

RESUMO

Vitamin B12, folate, and homocysteine are implicated in pivotal neurodegenerative mechanisms and partake in elders' mental decline. Findings on the association between vitamin-related biochemistry and cognitive abilities suggest that the structural and functional properties of the brain may represent an intermediate biomarker linking vitamin concentrations to cognition. Despite this, no previous study directly investigated whether vitamin B12, folate, and homocysteine levels are sufficient to explain individual neuropsychological profiles or, alternatively, whether the activity of brain regions modulated by these compounds better predicts cognition in elders. Here, we measured the relationship between vitamin blood concentrations, scores at seventeen neuropsychological tests, and brain activity of sixty-five elders spanning from normal to Mild Cognitive Impairment. We then evaluated whether task-related brain responses represent an intermediate phenotype, providing a better prediction of subjects' neuropsychological scores, as compared to the one obtained considering blood biochemistry only. We found that the hemodynamic activity of the right dorsal anterior cingulate cortex was positively associated (p value < 0.05 cluster corrected) with vitamin B12 concentrations, suggesting that elders with higher B12 levels had a more pronounced recruitment of this salience network region. Crucially, the activity of this area significantly predicted subjects' visual search and attention abilities (p value = 0.0023), whereas B12 levels per se failed to do so. Our results demonstrate that the relationship between blood biochemistry and elders' cognitive abilities is revealed when brain activity is included into the equation, thus highlighting the role of brain imaging as intermediate phenotype.


Assuntos
Encéfalo/diagnóstico por imagem , Cognição/fisiologia , Disfunção Cognitiva/sangue , Disfunção Cognitiva/diagnóstico por imagem , Hemodinâmica/fisiologia , Vitamina B 12/sangue , Idoso , Idoso de 80 Anos ou mais , Encéfalo/metabolismo , Disfunção Cognitiva/psicologia , Estudos de Coortes , Feminino , Humanos , Estudos Longitudinais , Masculino , Fenótipo
18.
Sci Rep ; 9(1): 7601, 2019 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-31110195

RESUMO

Biological vision relies on representations of the physical world at different levels of complexity. Relevant features span from simple low-level properties, as contrast and spatial frequencies, to object-based attributes, as shape and category. However, how these features are integrated into coherent percepts is still debated. Moreover, these dimensions often share common biases: for instance, stimuli from the same category (e.g., tools) may have similar shapes. Here, using magnetoencephalography, we revealed the temporal dynamics of feature processing in human subjects attending to objects from six semantic categories. By employing Relative Weights Analysis, we mitigated collinearity between model-based descriptions of stimuli and showed that low-level properties (contrast and spatial frequencies), shape (medial-axis) and category are represented within the same spatial locations early in time: 100-150 ms after stimulus onset. This fast and overlapping processing may result from independent parallel computations, with categorical representation emerging later than the onset of low-level feature processing, yet before shape coding. Categorical information is represented both before and after shape, suggesting a role for this feature in the refinement of categorical matching.

19.
Front Hum Neurosci ; 13: 32, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30837851

RESUMO

Classical studies have isolated a distributed network of temporal and frontal areas engaged in the neural representation of speech perception and production. With modern literature arguing against unique roles for these cortical regions, different theories have favored either neural code-sharing or cortical space-sharing, thus trying to explain the intertwined spatial and functional organization of motor and acoustic components across the fronto-temporal cortical network. In this context, the focus of attention has recently shifted toward specific model fitting, aimed at motor and/or acoustic space reconstruction in brain activity within the language network. Here, we tested a model based on acoustic properties (formants), and one based on motor properties (articulation parameters), where model-free decoding of evoked fMRI activity during perception, imagery, and production of vowels had been successful. Results revealed that phonological information organizes around formant structure during the perception of vowels; interestingly, such a model was reconstructed in a broad temporal region, outside of the primary auditory cortex, but also in the pars triangularis of the left inferior frontal gyrus. Conversely, articulatory features were not associated with brain activity in these regions. Overall, our results call for a degree of interdependence based on acoustic information, between the frontal and temporal ends of the language network.

20.
Front Behav Neurosci ; 12: 212, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30279649

RESUMO

"Autobiographical memory" (AM) refers to remote memories from one's own life. Previous neuroimaging studies have highlighted that voluntary retrieval processes from AM involve different forms of memory and cognitive functions. Thus, a complex and widespread brain functional network has been found to support AM. The present functional magnetic resonance imaging (fMRI) study used a multivariate approach to determine whether neural activity within the AM circuit would recognize memories of real autobiographical events, and to evaluate individual differences in the recruitment of this network. Fourteen right-handed females took part in the study. During scanning, subjects were presented with sentences representing a detail of a highly emotional real event (positive or negative) and were asked to indicate whether the sentence described something that had or had not really happened to them. Group analysis showed a set of cortical areas able to discriminate the truthfulness of the recalled events: medial prefrontal cortex, posterior cingulate/retrosplenial cortex, precuneus, bilateral angular, superior frontal gyri, and early visual cortical areas. Single-subject results showed that the decoding occurred at different time points. No differences were found between recalling a positive or a negative event. Our results show that the entire AM network is engaged in monitoring the veracity of AMs. This process is not affected by the emotional valence of the experience but rather by individual differences in cognitive strategies used to retrieve AMs.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA