RESUMEN
BACKGROUND: Air pollution, a reversible environmental factor, was significantly associated with the cognitive domains that are impaired in major depressive disorder (MDD), notably processing speed. Limited evidence explores the interactive effect of air pollution and the genetic risk of depression on cognition. This cross-sectional study aims to extend the research by specifically examining how this interaction influences depression-related cognitive impairment and resting-state brain function. METHODS: Eligible participants were 497 healthy adult volunteers (48.7% males, mean age 24.5) living in Beijing for at least 1 year and exposed to relatively high air pollution from the local community controlling for socioeconomic and genomic. Six months' ambient air pollution exposures were assessed based on residential addresses using monthly averages of fine particulate matter with a diameter of less than or equal to 2.5 µm (PM2.5). A cross-sectional analysis was conducted using functional magnetic resonance imaging (fMRI) and cognitive performance assessments. The polygenic risk score (PRS) of MDD was used to estimate genetic susceptibility. RESULTS: Using a general linear model and partial least square regression, we observed a negative association between resting-state local connectivity in precuneus and PRS-by-PM2.5 interactive effect (PFWE = 0.028), indicating that PM2.5 exposure reduced the spontaneous activity in precuneus in individuals at high genetic risk for MDD. DNA methylation and gene expression of the SLC30A3 gene, responsible for maintaining zinc-glutamate homeostasis, was suggestively associated with this local connectivity. For the global functional connectivity, the polygenic risk for MDD augmented the neural impact of PM2.5 exposure, especially in the frontal-parietal and frontal-limbic regions of the default mode network (PFDR < 0.05). In those genetically predisposed to MDD, increased PM2.5 exposure positively correlated with resting-state functional connectivity between the left angular gyrus and left cuneus gyrus. This connectivity was negatively associated with processing speed. CONCLUSIONS: Our cross-sectional study suggests that air pollution may be associated with an increased likelihood of cognitive impairment in individuals genetically predisposed to depression, potentially through alterations in the resting-state function of the occipitoparietal and default mode network.
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Contaminación del Aire , Imagen por Resonancia Magnética , Humanos , Masculino , Femenino , Estudios Transversales , Contaminación del Aire/efectos adversos , Adulto , Adulto Joven , Predisposición Genética a la Enfermedad , Material Particulado/efectos adversos , Trastorno Depresivo Mayor/genética , Trastorno Depresivo Mayor/fisiopatología , Lóbulo Parietal/fisiopatología , Lóbulo Parietal/diagnóstico por imagen , Beijing , Lóbulo Occipital/diagnóstico por imagen , Lóbulo Occipital/fisiopatología , Velocidad de ProcesamientoRESUMEN
The visual word form area in the occipitotemporal sulcus (here OTS-words) is crucial for reading and shows a preference for text stimuli. We hypothesized that this text preference may be driven by lexical processing. Hence, we performed three fMRI experiments (n = 15), systematically varying participants' task and stimulus, and separately evaluated middle mOTS-words and posterior pOTS-words. Experiment 1 contrasted text with other visual stimuli to identify both OTS-words subregions. Experiment 2 utilized an fMRI adaptation paradigm, presenting compound words as texts or emojis. In experiment 3, participants performed a lexical or color judgment task on compound words in text or emoji format. In experiment 2, pOTS-words, but not mOTS-words, showed fMRI adaptation for compound words in both formats. In experiment 3, both subregions showed higher responses to compound words in emoji format. Moreover, mOTS-words showed higher responses during the lexical judgment task and a task-stimulus interaction. Multivariate analyses revealed that distributed responses in pOTS-words encode stimulus and distributed responses in mOTS-words encode stimulus and task. Together, our findings suggest that the function of the OTS-words subregions goes beyond the specific visual processing of text and that these regions are flexibly recruited whenever semantic meaning needs to be assigned to visual input.
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Juicio , Imagen por Resonancia Magnética , Lectura , Humanos , Masculino , Femenino , Juicio/fisiología , Adulto Joven , Adulto , Estimulación Luminosa/métodos , Mapeo Encefálico , Reconocimiento Visual de Modelos/fisiología , Semántica , Lóbulo Temporal/fisiología , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Occipital/fisiología , Lóbulo Occipital/diagnóstico por imagenRESUMEN
AIMS: To examine whether functional connectivity (FC) of the occipital gyrus differs between patients with Parkinson's disease (PD) motor subtypes and healthy controls (HCs). METHODS: We enrolled 30 PD patients exhibiting tremor dominance (TD), 43 PD patients with postural instability and gait disturbance (PIGD), and 42 HCs. The occipital gyrus was partitioned into six areas of interest, as seed points, via the Anatomical Automatic Labeling template to compare the FC of the three groups and analyze the relationship of FC with clinical scales. RESULTS: Compared with the PIGD group, the TD group showed increased FC between the left superior occipital gyrus (SOG.L) and right median cingulate and paracingulate gyri (DCG.R)/right paracentral lobule/bilateral inferior parietal, but supramarginal and angular gyri; the left middle occipital gyrus (MOG.L) and left posterior cingulate gyrus (PCG.L); the MOG.R and SOG.L/right calcarine fissure and surrounding cortex/DCG.R/PCG.L/right cuneus; the left inferior occipital gyrus (IOG.L) and right caudate nucleus; and the IOG.R and PCG.L. CONCLUSION: Differentiated FC between the occipital gyrus and other brain areas within the PD motor subtypes, which may serve as neural markers to distinguish between patients with TD and PIGD PD.
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Vías Nerviosas , Lóbulo Occipital , Enfermedad de Parkinson , Lóbulo Occipital/diagnóstico por imagen , Lóbulo Occipital/patología , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/patología , Vías Nerviosas/patología , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Estudios RetrospectivosRESUMEN
The study of the neural substrates that serve conscious vision is one of the unsolved questions of cognitive neuroscience. So far, consciousness literature has endeavoured to disentangle which brain areas and in what order are involved in giving rise to visual awareness, but the problem of consciousness still remains unsolved. Availing of two different but complementary sources of data (i.e., Fast Optical Imaging and EEG), we sought to unravel the neural dynamics responsible for the emergence of a conscious visual experience. Our results revealed that conscious vision is characterized by a significant increase of activation in extra-striate visual areas, specifically in the Lateral Occipital Complex (LOC), and that, more interestingly, such activity occurred in the temporal window of the ERP component commonly thought to represent the electrophysiological signature of visual awareness, i.e., the Visual Awareness Negativity (VAN). Furthermore, Granger causality analysis, performed to further investigate the flow of activity occurring in the investigated areas, unveiled that neural processes relating to conscious perception mainly originated in LOC and subsequently spread towards visual and motor areas. In general, the results of the present study seem to advocate for an early contribution of LOC in conscious vision, thus suggesting that it could represent a reliable neural correlate of visual awareness. Conversely, striate visual areas, showing awareness-related activity only in later stages of stimulus processing, could be part of the cascade of neural events following awareness emergence.
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Estado de Conciencia , Electroencefalografía , Lóbulo Occipital , Percepción Visual , Humanos , Estado de Conciencia/fisiología , Percepción Visual/fisiología , Masculino , Femenino , Adulto , Adulto Joven , Lóbulo Occipital/fisiología , Lóbulo Occipital/diagnóstico por imagen , Corteza Visual Primaria/fisiología , Corteza Visual Primaria/diagnóstico por imagen , Mapeo Encefálico , Potenciales Evocados Visuales/fisiología , Corteza Visual/fisiología , Corteza Visual/diagnóstico por imagen , Concienciación/fisiologíaRESUMEN
Blindness is associated with heightened sensory abilities, such as improved hearing and tactile acuity. Moreover, recent evidence suggests that blind individuals are better than sighted individuals at perceiving their own heartbeat, suggesting enhanced interoceptive accuracy. Structural changes in the occipital cortex have been hypothesized as the basis of these behavioral enhancements. Indeed, several studies have shown that congenitally blind individuals have increased cortical thickness within occipital areas compared to sighted individuals, but how these structural differences relate to behavioral enhancements is unclear. This study investigated the relationship between cardiac interoceptive accuracy and cortical thickness in 23 congenitally blind individuals and 23 matched sighted controls. Our results show a significant positive correlation between performance in a heartbeat counting task and cortical thickness only in the blind group, indicating a connection between structural changes in occipital areas and blind individuals' enhanced ability to perceive heartbeats.
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Ceguera , Frecuencia Cardíaca , Lóbulo Occipital , Humanos , Masculino , Femenino , Lóbulo Occipital/diagnóstico por imagen , Lóbulo Occipital/fisiología , Adulto , Frecuencia Cardíaca/fisiología , Ceguera/fisiopatología , Persona de Mediana Edad , Imagen por Resonancia Magnética , Adulto Joven , Interocepción/fisiologíaRESUMEN
The occipital place area (OPA) is a scene-selective region on the lateral surface of human occipitotemporal cortex that spatially overlaps multiple visual field maps, as well as portions of cortex that are not currently defined as retinotopic. Here we combined population receptive field modeling and responses to scenes in a representational similarity analysis (RSA) framework to test the prediction that the OPA's visual field map divisions contribute uniquely to the overall pattern of scene selectivity within the OPA. Consistent with this prediction, the patterns of response to a set of complex scenes were heterogeneous between maps. To explain this heterogeneity, we tested the explanatory power of seven candidate models using RSA. These models spanned different scene dimensions (Content, Expanse, Distance), low- and high-level visual features, and navigational affordances. None of the tested models could account for the variation in scene response observed between the OPA's visual field maps. However, the heterogeneity in scene response was correlated with the differences in retinotopic profiles across maps. These data highlight the need to carefully examine the relationship between regions defined as category-selective and the underlying retinotopy, and they suggest that, in the case of the OPA, it may not be appropriate to conceptualize it as a single scene-selective region.
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Lóbulo Occipital , Estimulación Luminosa , Campos Visuales , Humanos , Campos Visuales/fisiología , Lóbulo Occipital/fisiología , Masculino , Adulto , Estimulación Luminosa/métodos , Femenino , Mapeo Encefálico/métodos , Retina/fisiología , Adulto Joven , Vías Visuales/fisiología , Reconocimiento Visual de Modelos/fisiología , Modelos NeurológicosRESUMEN
Occipital lobe epilepsy (OLE) is an uncommon type of extratemporal epilepsy constituting roughly 2-13% of symptomatic partial epilepsies and epilepsy surgery cases. Over two-thirds of patients with OLE present with two characteristics: (1) ictal semiology compatible with an occipital seizure focus (e.g., ictal blindness, visual perceptual disturbance, eye blinking, nystagmus), and (2) lateralizing features referable to the posterior cortex (e.g., visual field defects, contralateral head deviation). The remaining one-third of patients present with ≥ 2 seizure types, indicative of spread to other lobes. A common representation of this cortical spread is the altered mental status and generalized tonic-clonic activity seen in patient with OLE. While the key clinical symptoms include visual hallucinations, it may be difficult to elicit on history, especially from children, and are not always present.
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Epilepsias Parciales , Procedimientos Neuroquirúrgicos , Lóbulo Occipital , Humanos , Epilepsias Parciales/cirugía , Lóbulo Occipital/cirugía , Procedimientos Neuroquirúrgicos/métodos , Convulsiones/cirugía , ElectroencefalografíaRESUMEN
BACKGROUND: The neurobiological underpinnings of Autism Spectrum Disorder (ASD) are diverse and likely multifactorial. One possible mechanism is increased oxidative stress leading to altered neurodevelopment and brain function. However, this hypothesis has mostly been tested in post-mortem studies. So far, available in vivo studies in autistic individuals have reported no differences in glutathione (GSH) levels in frontal, occipital, and subcortical regions. However, these studies were limited by the technically challenging quantification of GSH, the main brain antioxidant molecule. This study aimed to overcome previous studies' limitations by using a GSH-tailored spectroscopy sequence and optimised quantification methodology to provide clarity on GSH levels in autistic adults. METHODS: We used spectral editing proton-magnetic resonance spectroscopy (1H-MRS) combined with linear combination model fitting to quantify GSH in the dorsomedial prefrontal cortex (DMPFC) and medial occipital cortex (mOCC) of autistic and non-autistic adults (male and female). We compared GSH levels between groups. We also examined correlations between GSH and current autism symptoms, measured using the Autism Quotient (AQ). RESULTS: Data were available from 31 adult autistic participants (24 males, 7 females) and 40 non-autistic participants (21 males, 16 females); the largest sample to date. The GSH levels did not differ between groups in either region. No correlations with AQ were observed. CONCLUSION: GSH levels as measured using 1H-MRS are unaltered in the DMPFC and mOCC regions of autistic adults, suggesting that oxidative stress in these cortical regions is not a marked neurobiological signature of ASD.
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Trastorno del Espectro Autista , Trastorno Autístico , Glutatión , Lóbulo Occipital , Humanos , Masculino , Femenino , Glutatión/metabolismo , Glutatión/análisis , Adulto , Lóbulo Occipital/metabolismo , Lóbulo Occipital/diagnóstico por imagen , Trastorno del Espectro Autista/metabolismo , Trastorno Autístico/metabolismo , Adulto Joven , Espectroscopía de Protones por Resonancia Magnética , Lóbulo Frontal/metabolismo , Estrés Oxidativo , Persona de Mediana Edad , Corteza Prefrontal/metabolismo , Corteza Prefrontal/diagnóstico por imagenRESUMEN
The patient was an 85-year-old man with a one-year history of difficulty reading kana. Neuropsychological evaluation revealed kana (phonogram)-selective reading impairment and kanji (ideogram)-dominant writing impairment. MRI revealed significant cerebral atrophy in the left occipital cortex, leading to the clinical diagnosis of posterior cortical atrophy (PCA). Cerebrospinal fluid amyloid ß1-42 levels were reduced, and amyloid PET showed accumulation in the posterior cingulate cortex, precuneus, and frontal lobe. In contrast, tau PET showed no accumulation in the atrophied brain areas. Episodes of REM sleep behavior disorder and decreased uptake on meta-iodobenzylguanidine (MIBG) myocardial scintigraphy suggested the involvement of Lewy body pathology. PCA with distinct laterality has been rarely reported, and |this is the first case to present Kana-selective reading impairment and Kanji-dominant writing impairment with neurodegenerative background.
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Atrofia , Imagen por Resonancia Magnética , Humanos , Masculino , Anciano de 80 o más Años , Tomografía de Emisión de Positrones , Dislexia/etiología , Corteza Cerebral/patología , Corteza Cerebral/diagnóstico por imagen , Biomarcadores/líquido cefalorraquídeo , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/líquido cefalorraquídeo , Lóbulo Occipital/patología , Lóbulo Occipital/diagnóstico por imagen , Cuerpos de Lewy/patología , Trastorno de la Conducta del Sueño REM/etiología , Trastorno de la Conducta del Sueño REM/diagnóstico por imagen , Trastorno de la Conducta del Sueño REM/diagnósticoRESUMEN
To interpret our surroundings, the brain uses a visual categorization process. Current theories and models suggest that this process comprises a hierarchy of different computations that transforms complex, high-dimensional inputs into lower-dimensional representations (i.e., manifolds) in support of multiple categorization behaviors. Here, we tested this hypothesis by analyzing these transformations reflected in dynamic MEG source activity while individual participants actively categorized the same stimuli according to different tasks: face expression, face gender, pedestrian gender, and vehicle type. Results reveal three transformation stages guided by the pre-frontal cortex. At stage 1 (high-dimensional, 50-120 ms), occipital sources represent both task-relevant and task-irrelevant stimulus features; task-relevant features advance into higher ventral/dorsal regions, whereas task-irrelevant features halt at the occipital-temporal junction. At stage 2 (121-150 ms), stimulus feature representations reduce to lower-dimensional manifolds, which then transform into the task-relevant features underlying categorization behavior over stage 3 (161-350 ms). Our findings shed light on how the brain's network mechanisms transform high-dimensional inputs into specific feature manifolds that support multiple categorization behaviors.
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Lóbulo Occipital , Humanos , Masculino , Femenino , Adulto , Lóbulo Occipital/fisiología , Adulto Joven , Corteza Prefrontal/fisiología , MagnetoencefalografíaRESUMEN
Vision in humans and other primates enlists parallel processing streams in the dorsal and ventral visual cortex, known to support spatial and object processing, respectively. These streams are bridged, however, by a prominent white matter tract, the vertical occipital fasciculus (VOF), identified in both classical neuroanatomy and recent diffusion-weighted magnetic resonance imaging (dMRI) studies. Understanding the evolution of the VOF may shed light on its origin, function, and role in visually guided behaviors. To this end, we acquired high-resolution dMRI data from the brains of select mammalian species, including anthropoid and strepsirrhine primates, a tree shrew, rodents, and carnivores. In each species, we attempted to delineate the VOF after first locating the optic radiations in the occipital white matter. In all primate species examined, the optic radiation was flanked laterally by a prominent and coherent white matter fasciculus recognizable as the VOF. By contrast, the equivalent analysis applied to four non-primate species from the same superorder as primates (tree shrew, ground squirrel, paca, and rat) failed to reveal white matter tracts in the equivalent location. Clear evidence for a VOF was also absent in two larger carnivore species (ferret and fox). Although we cannot rule out the existence of minor or differently organized homologous fiber pathways in the non-primate species, the results suggest that the VOF has greatly expanded, or possibly emerged, in the primate lineage. This adaptation likely facilitated the evolution of unique visually guided behaviors in primates, with direct impacts on manual object manipulation, social interactions, and arboreal locomotion.
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Primates , Corteza Visual , Sustancia Blanca , Animales , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/anatomía & histología , Primates/anatomía & histología , Primates/fisiología , Corteza Visual/fisiología , Corteza Visual/diagnóstico por imagen , Corteza Visual/anatomía & histología , Vías Visuales/anatomía & histología , Vías Visuales/fisiología , Vías Visuales/diagnóstico por imagen , Lóbulo Occipital/anatomía & histología , Lóbulo Occipital/fisiología , Lóbulo Occipital/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética , Carnívoros/anatomía & histología , Carnívoros/fisiología , Especificidad de la Especie , Evolución Biológica , Roedores/anatomía & histología , Roedores/fisiologíaRESUMEN
BACKGROUND: Prior work has shown that transcranial alternating current stimulation (tACS) of parietooccipital alpha oscillations (8-14 Hz) can modulate working memory (WM) performance as a function of the phase lag to endogenous oscillations. However, leveraging this effect using real-time phase-tuned tACS has not been feasible so far due to stimulation artifacts preventing continuous phase tracking. OBJECTIVES AND HYPOTHESIS: We aimed to develop a system that tracks and adapts the phase lag between tACS and ongoing parietooccipital alpha oscillations in real-time. We hypothesized that such real-time phase-tuned tACS enhances working memory performance, depending on the phase lag. METHODS: We developed real-time phase-tuned closed-loop amplitude-modulated tACS (CLAM-tACS) targeting parietooccipital alpha oscillations. CLAM-tACS was applied at six different phase lags relative to ongoing alpha oscillations while participants (N = 21) performed a working memory task. To exclude that behavioral effects of CLAM-tACS were mediated by other factors such as sensory co-stimulation, a second group of participants (N = 25) received equivalent stimulation of the forehead. RESULTS: WM accuracy improved in a phase lag dependent manner (p = 0.0350) in the group receiving parietooccipital stimulation, with the strongest enhancement observed at 330° phase lag between tACS and ongoing alpha oscillations (p = 0.00273, d = 0.976). Moreover, across participants, modulation of frontoparietal alpha oscillations correlated both in amplitude (p = 0.0248) and phase (p = 0.0270) with the modulation of WM accuracy. No such effects were observed in the control group receiving frontal stimulation. CONCLUSIONS: Our results demonstrate the feasibility and efficacy of real-time phase-tuned CLAM-tACS in modulating both brain activity and behavior, thereby paving the way for further investigation into brain-behavior relationships and the exploration of innovative therapeutic applications.
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Ritmo alfa , Memoria a Corto Plazo , Estimulación Transcraneal de Corriente Directa , Humanos , Memoria a Corto Plazo/fisiología , Estimulación Transcraneal de Corriente Directa/métodos , Masculino , Femenino , Adulto , Ritmo alfa/fisiología , Adulto Joven , Lóbulo Parietal/fisiología , Lóbulo Occipital/fisiologíaRESUMEN
In everyday life, people need to respond appropriately to many types of emotional stimuli. Here, we investigate whether human occipital-temporal cortex (OTC) shows co-representation of the semantic category and affective content of visual stimuli. We also explore whether OTC transformation of semantic and affective features extracts information of value for guiding behavior. Participants viewed 1620 emotional natural images while functional magnetic resonance imaging data were acquired. Using voxel-wise modeling we show widespread tuning to semantic and affective image features across OTC. The top three principal components underlying OTC voxel-wise responses to image features encoded stimulus animacy, stimulus arousal and interactions of animacy with stimulus valence and arousal. At low to moderate dimensionality, OTC tuning patterns predicted behavioral responses linked to each image better than regressors directly based on image features. This is consistent with OTC representing stimulus semantic category and affective content in a manner suited to guiding behavior.
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Emociones , Imagen por Resonancia Magnética , Lóbulo Occipital , Semántica , Lóbulo Temporal , Humanos , Femenino , Masculino , Imagen por Resonancia Magnética/métodos , Lóbulo Temporal/fisiología , Lóbulo Temporal/diagnóstico por imagen , Adulto , Lóbulo Occipital/fisiología , Lóbulo Occipital/diagnóstico por imagen , Adulto Joven , Emociones/fisiología , Mapeo Encefálico , Estimulación Luminosa , Afecto/fisiología , Nivel de Alerta/fisiologíaRESUMEN
Contextual features are integral to episodic memories; yet, we know little about context effects on pattern separation, a hippocampal function promoting orthogonalization of overlapping memory representations. Recent studies suggested that various extrahippocampal brain regions support pattern separation; however, the specific role of the parahippocampal cortex-a region involved in context representation-in pattern separation has not yet been studied. Here, we investigated the contribution of the parahippocampal cortex (specifically, the parahippocampal place area) to context reinstatement effects on mnemonic discrimination, using functional magnetic resonance imaging. During scanning, participants saw object images on unique context scenes, followed by a recognition task involving the repetitions of encoded objects or visually similar lures on either their original context or a lure context. Context reinstatement at retrieval improved item recognition but hindered mnemonic discrimination. Crucially, our region of interest analyses of the parahippocampal place area and an object-selective visual area, the lateral occipital cortex indicated that while during successful mnemonic decisions parahippocampal place area activity decreased for old contexts compared to lure contexts irrespective of object novelty, lateral occipital cortex activity differentiated between old and lure objects exclusively. These results imply that pattern separation of contextual and item-specific memory features may be differentially aided by scene and object-selective cortical areas.
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Imagen por Resonancia Magnética , Lóbulo Occipital , Giro Parahipocampal , Reconocimiento Visual de Modelos , Reconocimiento en Psicología , Humanos , Femenino , Masculino , Giro Parahipocampal/fisiología , Giro Parahipocampal/diagnóstico por imagen , Adulto Joven , Adulto , Lóbulo Occipital/fisiología , Lóbulo Occipital/diagnóstico por imagen , Reconocimiento Visual de Modelos/fisiología , Reconocimiento en Psicología/fisiología , Mapeo Encefálico/métodos , Estimulación Luminosa/métodos , Memoria EpisódicaRESUMEN
Although three-dimensional visual training (3DVT) has been used for myopia intervention, its neural mechanisms remain largely unknown. In this study, visual function was examined before and after 3DVT, while resting-state EEG-fNIRS signals were recorded from 38 myopic participants. A graph theoretical analysis was applied to compute the neurovascular properties, including static brain networks (SBNs), dynamic brain networks (DBNs), and dynamic neurovascular coupling (DNC). Correlations between the changes in neurovascular properties and the changes in visual functions were calculated. After 3DVT, the local efficiency and node efficiency in the frontal lobes increased in the SBNs constructed from EEG δ -band; the global efficiency and node efficiency in the frontal-parietal lobes decreased in the DBNs variability constructed from EEG δ -band. For the DNC constructed with EEG α -band and oxyhemoglobin (HbO), the local efficiency decreased, for EEG α -band and deoxyhemoglobin (HbR), the node efficiency in the frontal-occipital lobes decreased. For the SBNs constructed from HbO, the functional connectivity (FC) between the frontal-occipital lobes increased. The DNC constructed between the FC of the frontal-parietal lobes from EEG ß -band and the FC of the frontal-occipital lobes from HbO increased, and between the FC of the frontal-occipital lobes from EEG ß -band and the FC of the inter-frontal lobes from HbR increased. The neurovascular properties were significantly correlated with the amplitude of accommodation and accommodative facility. The result indicated the positive effects of 3DVT on myopic participants, including improved efficiency of brain networks, increased FC of SBNs and DNC, and enhanced binocular accommodation functions.
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Acomodación Ocular , Electroencefalografía , Miopía , Espectroscopía Infrarroja Corta , Visión Binocular , Humanos , Masculino , Femenino , Miopía/fisiopatología , Miopía/rehabilitación , Visión Binocular/fisiología , Acomodación Ocular/fisiología , Adulto Joven , Adulto , Lóbulo Parietal/fisiopatología , Lóbulo Parietal/diagnóstico por imagen , Lóbulo Frontal/fisiopatología , Acoplamiento Neurovascular/fisiología , Oxihemoglobinas/metabolismo , Red Nerviosa/fisiopatología , Hemoglobinas/metabolismo , Hemoglobinas/análisis , Adaptación Fisiológica , Encéfalo/fisiopatología , Encéfalo/diagnóstico por imagen , Lóbulo Occipital/fisiopatologíaRESUMEN
High-definition transcranial direct current stimulation (HD-tDCS) is a non-invasive brain stimulation technique that has been shown to be safe and effective in modulating neuronal activity. The present study investigates the effect of anodal HD-tDCS on haptic object perception and memory through stimulation of the lateral occipital complex (LOC), a structure that has been shown to be involved in both visual and haptic object recognition. In this single-blind, sham-controlled, between-subjects study, blindfolded healthy, sighted participants used their right (dominant) hand to perform haptic discrimination and recognition tasks with 3D-printed, novel objects called "Greebles" while receiving 20 min of 2 milliamp (mA) anodal stimulation (or sham) to the left or right LOC. Compared to sham, those who received left LOC stimulation (contralateral to the hand used) showed an improvement in haptic object recognition but not discrimination-a finding that was evident from the start of the behavioral tasks. A second experiment showed that this effect was not observed with right LOC stimulation (ipsilateral to the hand used). These results suggest that HD-tDCS to the left LOC can improve recognition of objects perceived via touch. Overall, this work sheds light on the LOC as a multimodal structure that plays a key role in object recognition in both the visual and haptic modalities.
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Lóbulo Occipital , Reconocimiento en Psicología , Estimulación Transcraneal de Corriente Directa , Humanos , Masculino , Femenino , Lóbulo Occipital/fisiología , Adulto Joven , Adulto , Estimulación Transcraneal de Corriente Directa/métodos , Reconocimiento en Psicología/fisiología , Método Simple Ciego , Percepción del Tacto/fisiología , Discriminación en Psicología/fisiología , Lateralidad Funcional/fisiologíaRESUMEN
Sensory development is a complex process that can influence physiological and pathological factors. In laterally-eyed mammals, monocular enucleation (ME) during development and the subsequent lack of external sensory stimuli can result in permanent morphological and physiological changes. Malnutrition, especially in early life, also can cause permanent morphofunctional changes due to inadequate nutrient intake in both hemispheres. This study investigated the effects of early (postnatal day 7) ME and malnutrition during the suckling period on cortical excitability in adulthood (110-140 days of life). For this, we compared the speed propagation of cortical spreading depression in the occipital and parietal cortex of malnourished and well-nourished adult rats, previously suckled small-sized litters with three pups (L3/dam) medium-sized litters with six pups (L6/dam), and large-sized litters with twelve pups (L12/dam). The CSD velocity was augmented by the ME in the contralateral side of the removed eye in the parietal and occipital cortex. These findings suggest that visual sensory input deprivation is associated with permanent functional changes in the visual pathways, which can alter cortical excitability and lead to modifications in CSD propagation.
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Depresión de Propagación Cortical , Enucleación del Ojo , Desnutrición , Ratas Wistar , Animales , Depresión de Propagación Cortical/fisiología , Desnutrición/fisiopatología , Desnutrición/complicaciones , Ratas , Masculino , Femenino , Animales Recién Nacidos , Lóbulo Occipital/fisiopatología , Lóbulo Parietal/fisiopatologíaRESUMEN
BACKGROUND/OBJECTIVES: Stroke damage to the primary visual cortex induces large, homonymous visual field defects that impair daily living. Here, we asked if vision-related quality of life (VR-QoL) is impacted by time since stroke. SUBJECTS/METHODS: We conducted a retrospective meta-analysis of 95 occipital stroke patients (female/male = 26/69, 27-78 years old, 0.5-373.5 months poststroke) in whom VR-QoL was estimated using the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ) and its 10-item neuro-ophthalmic supplement (Neuro10). Visual deficit severity was represented by the perimetric mean deviation (PMD) calculated from 24-2 Humphrey visual fields. Data were compared with published cohorts of visually intact controls. The relationship between VR-QoL and time poststroke was assessed across participants, adjusting for deficit severity and age with a multiple linear regression analysis. RESULTS: Occipital stroke patients had significantly lower NEI-VFQ and Neuro10 composite scores than controls. All subscale scores describing specific aspects of visual ability and functioning were impaired except for ocular pain and general health, which did not differ significantly from controls. Surprisingly, visual deficit severity was not correlated with either composite score, both of which increased with time poststroke, even when adjusting for PMD and age. CONCLUSIONS: VR-QoL appears to improve with time postoccipital stroke, irrespective of visual deficit size or patient age at insult. This may reflect the natural development of compensatory strategies and lifestyle adjustments. Thus, future studies examining the impact of rehabilitation on daily living in this patient population should consider the possibility that their VR-QoL may change gradually over time, even without therapeutic intervention.
Asunto(s)
Calidad de Vida , Accidente Cerebrovascular , Humanos , Femenino , Persona de Mediana Edad , Masculino , Accidente Cerebrovascular/fisiopatología , Accidente Cerebrovascular/complicaciones , Anciano , Adulto , Estudios Retrospectivos , Trastornos de la Visión/fisiopatología , Trastornos de la Visión/etiología , Lóbulo Occipital/fisiopatología , Campos Visuales/fisiologíaRESUMEN
Approximately one third of the population is prone to motion sickness (MS), which is associated with the dysfunction in the integration of sensory inputs. Transcranial alternating current stimulation (tACS) has been widely used to modulate neurological functions by affecting neural oscillation. However, it has not been applied in the treatment of motion sickness. This study aims to investigate changes in brain oscillations during exposure to MS stimuli and to further explore the potential impact of tACS with the corresponding frequency and site on MS symptoms. A total of 19 subjects were recruited to be exposed to Coriolis stimuli to complete an inducing session. After that, they were randomly assigned to tACS stimulation group or sham stimulation group to complete a stimulation session. Electroencephalography (EEG), electrocardiogram, and galvanic skin response were recorded during the experiment. All the subjects suffering from obvious MS symptoms after inducing session were observed that alpha power of four channels of parieto-occipital lobe significantly decreased (P7: t =3.589, p <0.001; P8: t =2.667, p <0.05; O1: t =3.556, p <0.001; O2: t =2.667, p <0.05). Based on this, tACS group received the tACS stimulation at 10Hz from Oz to CPz. Compared to sham group, tACS stimulation significantly improved behavioral performance and entrained the alpha oscillation in individuals whose alpha power decrease during the inducing session. The findings show that parieto-occipital alpha oscillation plays a critical role in the integration of sensory inputs, and alpha tACS on parieto-occipital can become a potential method to mitigate MS symptoms.
Asunto(s)
Ritmo alfa , Electroencefalografía , Respuesta Galvánica de la Piel , Mareo por Movimiento , Lóbulo Occipital , Lóbulo Parietal , Estimulación Transcraneal de Corriente Directa , Humanos , Mareo por Movimiento/prevención & control , Mareo por Movimiento/fisiopatología , Masculino , Lóbulo Occipital/fisiología , Femenino , Lóbulo Parietal/fisiología , Adulto , Estimulación Transcraneal de Corriente Directa/métodos , Adulto Joven , Respuesta Galvánica de la Piel/fisiología , ElectrocardiografíaRESUMEN
Optic Aphasia (OA) and Associative Visual Agnosia (AVA) are neuropsychological disorders characterized by impaired naming on visual presentation. From a cognitive point of view, while stimulus identification is largely unimpaired in OA (where access to semantic knowledge is still possible), in AVA it is not. OA has been linked with right hemianopia and disconnection of the occipital right-hemisphere (RH) visual processing from the left hemisphere (LH) language areas.In this paper, we describe the case of AA, an 81-year-old housewife suffering from a deficit in naming visually presented stimuli after left occipital lesion and damage to the interhemispheric splenial pathway. AA has been tested through a set of tasks assessing different levels of visual object processing. We discuss behavioral performance as well as the pattern of lesion and disconnection in relation to a neurocognitive model adapted from Luzzatti and colleagues (1998). Despite the complexity of the neuropsychological picture, behavioral data suggest that semantic access from visual input is possible, while a lesion-based structural disconnectome investigation demonstrated the splenial involvement.Altogether, neuropsychological and neuroanatomical findings support the assumption of visuo-verbal callosal disconnection compatible with a diagnosis of OA.