Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Hum Brain Mapp ; 45(1): e26569, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38224540

RESUMEN

Successful visual word recognition requires the integration of phonological and semantic information, which is supported by the dorsal and ventral pathways in the brain. However, the functional specialization or interaction of these pathways during phonological and semantic processing remains unclear. Previous research has been limited by its dependence on correlational functional magnetic resonance imaging (fMRI) results or causal validation using patient populations, which are susceptible to confounds such as plasticity and lesion characteristics. To address this, the present study employed continuous theta-burst stimulation combined with fMRI in a within-subject design to assess rapid adaptation in regional activity and functional connectivity of the dorsal and ventral pathways during phonological and semantic tasks. This assessment followed the precise inhibition of the left inferior parietal lobule and anterior temporal lobe in the dorsal and ventral pathways, respectively. Our results reveal that both the dorsal and ventral pathways were activated during phonological and semantic processing, while the adaptation activation and interactive network were modulated by the task type and inhibited region. The two pathways exhibited interconnectivity in phonological processing, and disruption of either pathway led to rapid adaptation across both pathways. In contrast, only the ventral pathway exhibited connectivity in semantic processing, and disruption of this pathway alone resulted in adaptive effects primarily in the ventral pathway. These findings provide essential evidence supporting the interactive theory, phonological information processing in particular, potentially providing meaningful implications for clinical populations.


Asunto(s)
Imagen por Resonancia Magnética , Semántica , Humanos , Imagen por Resonancia Magnética/métodos , Mapeo Encefálico/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Lóbulo Temporal/fisiología
2.
Cereb Cortex ; 33(24): 11526-11540, 2023 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-37851850

RESUMEN

The occipital cortex is the visual processing center in the mammalian brain. An unanswered scientific question pertains to the impact of congenital visual deprivation on the development of various profiles within the occipital network. To address this issue, we recruited 30 congenitally blind participants (8 children and 22 adults) as well as 31 sighted participants (10 children and 21 adults). Our investigation focused on identifying the gray matter regions and white matter connections within the occipital cortex, alongside behavioral measures, that demonstrated different developmental patterns between blind and sighted individuals. We discovered significant developmental changes in the gray matter regions and white matter connections of the occipital cortex among blind individuals from childhood to adulthood, in comparison with sighted individuals. Moreover, some of these structures exhibited cognitive functional reorganization. Specifically, in blind adults, the posterior occipital regions (left calcarine fissure and right middle occipital gyrus) showed reorganization of tactile perception, and the forceps major tracts were reorganized for braille reading. These plastic changes in blind individuals may be attributed to experience-dependent neuronal apoptosis, pruning, and myelination. These findings provide valuable insights into the longitudinal neuroanatomical and cognitive functional plasticity of the occipital network following long-term visual deprivation.


Asunto(s)
Imagen por Resonancia Magnética , Lóbulo Occipital , Adulto , Niño , Humanos , Adolescente , Adulto Joven , Lóbulo Occipital/diagnóstico por imagen , Encéfalo , Ceguera , Corteza Cerebral , Plasticidad Neuronal/fisiología
3.
Drug Des Devel Ther ; 17: 771-790, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36925998

RESUMEN

Astragali Radix is a significant traditional Chinese medication, and has a long history of clinical application in the treatment of diabetes mellitus (DM) and its complications. AS-IV is an active saponin isolated from it. Modern pharmacological study shows that AS-IV has anti-inflammatory, anti-oxidant and immunomodulatory activities. The popular inflammatory etiology of diabetes suggests that DM is a natural immune and low-grade inflammatory disease. Pharmacological intervention of the inflammatory response may provide promising and alternative approaches for the prevention and treatment of DM and its complications. Therefore, this article focuses on the potential of AS-IV in the treatment of DM from the perspective of an anti-inflammatory molecular basis. AS-IV plays a role by regulating a variety of anti-inflammatory pathways in multiple organs, tissues and target cells throughout the body. The blockade of the NF-κB inflammatory signaling pathway may be the central link of AS-IV's anti-inflammatory effect, resulting in a reduction in the tissue structure and function damage stimulated by inflammatory factors. In addition, AS-IV can delay the onset of DM and its complications by inhibiting inflammation-related oxidative stress, fibrosis and apoptosis signals. In conclusion, AS-IV has therapeutic prospects from the perspective of reducing the inflammation of DM and its complications. An in-depth study on the anti-inflammatory mechanism of AS-IV is of great significance for the effective use of Chinese herbal medicine and the promotion of its status and influence on the world.


Asunto(s)
Diabetes Mellitus , Saponinas , Humanos , Diabetes Mellitus/tratamiento farmacológico , Saponinas/farmacología , Saponinas/uso terapéutico , Saponinas/química , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Inflamación/tratamiento farmacológico , Antioxidantes
4.
Neuroimage ; 264: 119722, 2022 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-36323383

RESUMEN

The thalamus is heavily involved in relaying sensory signals to the cerebral cortex. A relevant issue is how the deprivation of congenital visual sensory information modulates the development of the thalamocortical network. The answer is unclear because previous studies on this topic did not investigate network development, structure-function combinations, and cognition-related behaviors in the same study. To overcome these limitations, we recruited 30 congenitally blind subjects (8 children, 22 adults) and 31 sighted subjects (10 children, 21 adults), and conducted multiple analyses [i.e., gray matter volume (GMV) analysis using the voxel-based morphometry (VBM) method, resting-state functional connectivity (FC), and brain-behavior correlation]. We found that congenital blindness elicited significant changes in the development of GMV in visual and somatosensory thalamic regions. Blindness also resulted in significant changes in the development of FC between somatosensory thalamic regions and visual cortical regions as well as advanced information processing regions. Moreover, the somatosensory thalamic regions and their FCs with visual cortical regions were reorganized to process high-level tactile language information in blind individuals. These findings provide a refined understanding of the neuroanatomical and functional plasticity of the thalamocortical network.


Asunto(s)
Imagen por Resonancia Magnética , Corteza Visual , Adulto , Niño , Humanos , Imagen por Resonancia Magnética/métodos , Corteza Visual/diagnóstico por imagen , Ceguera , Tálamo/diagnóstico por imagen , Sustancia Gris/diagnóstico por imagen
5.
J Affect Disord ; 311: 595-603, 2022 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-35662573

RESUMEN

BACKGROUND: While previous neuroimaging studies are mainly focused on dichotomous classification of obsessive-compulsive disorder (OCD) from controls, predicting continuous severity of specific symptom is also pivotal to clinical diagnosis and treatment. METHODS: We applied a machine-learning approach, connectome-based predictive modeling, on functional and structural brain networks constructed from resting-state functional magnetic resonance imaging and diffusion tensor imaging data to decode compulsions and obsessions of fifty-four patients with OCD. RESULTS: We successfully predicted individualized compulsions with a positive model of structural brain network and with a negative model of functional brain network. The structural predictive brain network comprises the motor cortex, cerebellum and limbic lobe, which are involved in basic motor control, motor execution and emotion processing, respectively. The functional predictive brain network is composed by the prefrontal and limbic systems which are related to cognitive and affective control. Computational lesion analysis shows that functional connectivity among the salience network (SN), the frontal parietal network and the default mode network, as well as structural connectivity within the SN are vital in the individualized prediction of compulsions in OCD. LIMITATIONS: There was no external validation of large samples to test the robustness of our predictive model. CONCLUSIONS: These findings provide the first evidence for the predictive role of the triple network model in individualized compulsions and have important implications in diagnosis, prognosis and treatment of patients with OCD.


Asunto(s)
Conectoma , Trastorno Obsesivo Compulsivo , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Conectoma/métodos , Imagen de Difusión Tensora , Humanos , Imagen por Resonancia Magnética , Trastorno Obsesivo Compulsivo/diagnóstico por imagen
6.
Hum Brain Mapp ; 42(12): 3833-3844, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-34050701

RESUMEN

A large proportion of patients with obsessive-compulsive disorder (OCD) respond unsatisfactorily to pharmacological and psychological treatments. An alternative novel treatment for these patients is repetitive transcranial magnetic stimulation (rTMS). This study aimed to investigate the underlying neural mechanism of rTMS treatment in OCD patients. A total of 37 patients with OCD were randomized to receive real or sham 1-Hz rTMS (14 days, 30 min/day) over the right pre-supplementary motor area (preSMA). Resting-state functional magnetic resonance imaging data were collected before and after rTMS treatment. The individualized target was defined by a personalized functional connectivity map of the subthalamic nucleus. After treatment, patients in the real group showed a better improvement in the Yale-Brown Obsessive Compulsive Scale than the sham group (F1,35  = 6.0, p = .019). To show the neural mechanism involved, we identified an "ideal target connectivity" before treatment. Leave-one-out cross-validation indicated that this connectivity pattern can significantly predict patients' symptom improvements (r = .60, p = .009). After real treatment, the average connectivity strength of the target network significantly decreased in the real but not in the sham group. This network-level change was cross-validated in three independent datasets. Altogether, these findings suggest that personalized magnetic stimulation on preSMA may alleviate obsessive-compulsive symptoms by decreasing the connectivity strength of the target network.


Asunto(s)
Conectoma , Corteza Motora/fisiopatología , Red Nerviosa/fisiopatología , Trastorno Obsesivo Compulsivo/fisiopatología , Trastorno Obsesivo Compulsivo/terapia , Núcleo Subtalámico/fisiopatología , Estimulación Magnética Transcraneal , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Corteza Motora/diagnóstico por imagen , Red Nerviosa/diagnóstico por imagen , Trastorno Obsesivo Compulsivo/diagnóstico por imagen , Núcleo Subtalámico/diagnóstico por imagen , Resultado del Tratamiento
7.
Front Hum Neurosci ; 14: 585086, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33192420

RESUMEN

Impaired decision-making is well documented in obsessive-compulsive disorder (OCD) and a range of electrophysiological and functional neuroimaging measures have begun to reveal the pathological mechanisms that underlie the decision-making process. Obsessive-compulsive personality disorder (OCPD) has core symptoms that often overlap with OCD, but similarities between these disorders at the behavioral and neurological levels are often unclear, including whether OCPD exhibits similar decision-making deficits and shared neurological dysfunction. To address these issues, we examined 24 cases of OCD, 19 cases of OCPD, and 26 matched normal control (NC) subjects during the revised Iowa Gambling Task (IGT) using event-related potentials (ERPs). The net IGT scores were lower for OCD subjects than for OCPD or NC subjects, thus indicating that OCD subjects chose more disadvantageous options and were "short-sighted" with regards to information. The feedback-related negativity (FRN) waveform (lose-win) was larger in both OCD and OCPD subjects, which suggested that obstacles exist in the feedback process. Consequently, these subjects might share similar neural mechanisms under ambiguous decision-making circumstances. Furthermore, IGT net scores were significantly and negatively correlated with Hamilton Anxiety Rating Scale (HAMA) and Hamilton Depression Rating Scale (HAMD) scales. This implies that more severe obsessive-compulsive symptoms inspired more negative emotions that led to worse decision-making ability. Therefore, although similar neural mechanisms might exist, this led to different behaviors in which OCPD is associated with better behavioral performance compared to OCD patients.

8.
Proc Natl Acad Sci U S A ; 116(9): 3799-3804, 2019 02 26.
Artículo en Inglés | MEDLINE | ID: mdl-30808765

RESUMEN

Obsessive-compulsive disorder (OCD) affects ∼1 to 3% of the world's population. However, the neural mechanisms underlying the excessive checking symptoms in OCD are not fully understood. Using viral neuronal tracing in mice, we found that glutamatergic neurons from the basolateral amygdala (BLAGlu) project onto both medial prefrontal cortex glutamate (mPFCGlu) and GABA (mPFCGABA) neurons that locally innervate mPFCGlu neurons. Next, we developed an OCD checking mouse model with quinpirole-induced repetitive checking behaviors. This model demonstrated decreased glutamatergic mPFC microcircuit activity regulated by enhanced BLAGlu inputs. Optical or chemogenetic manipulations of this maladaptive circuitry restored the behavioral response. These findings were verified in a mouse functional magnetic resonance imaging (fMRI) study, in which the BLA-mPFC functional connectivity was increased in OCD mice. Together, these findings define a unique BLAGlu→mPFCGABA→Glu circuit that controls the checking symptoms of OCD.


Asunto(s)
Amígdala del Cerebelo/metabolismo , Complejo Nuclear Basolateral/metabolismo , Neuronas/metabolismo , Trastorno Obsesivo Compulsivo/metabolismo , Amígdala del Cerebelo/diagnóstico por imagen , Amígdala del Cerebelo/fisiopatología , Animales , Complejo Nuclear Basolateral/diagnóstico por imagen , Complejo Nuclear Basolateral/fisiopatología , Modelos Animales de Enfermedad , Ácido Glutámico/metabolismo , Humanos , Imagen por Resonancia Magnética , Ratones , Vías Nerviosas/metabolismo , Vías Nerviosas/fisiopatología , Neuronas/patología , Trastorno Obsesivo Compulsivo/diagnóstico por imagen , Trastorno Obsesivo Compulsivo/fisiopatología , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/metabolismo , Corteza Prefrontal/fisiopatología
9.
Nanomicro Lett ; 8(4): 347-357, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-30460293

RESUMEN

ABSTRACT: A solvent-assisted methodology has been developed to synthesize CH3NH3PbI3 perovskite absorber layers. It involved the use of a mixed solvent of CH3NH3I, PbI2, γ-butyrolactone, and dimethyl sulfoxide (DMSO) followed by the addition of chlorobenzene (CB). The method produced ultra-flat and dense perovskite capping layers atop mesoporous TiO2 films, enabling a remarkable improvement in the performance of free hole transport material (HTM) carbon electrode-based perovskite solar cells (PSCs). Toluene (TO) was also studied as an additional solvent for comparison. At the annealing temperature of 100 °C, the fabricated HTM-free PSCs based on drop-casting CB demonstrated power conversion efficiency (PCE) of 9.73 %, which is 36 and 71 % higher than those fabricated from the perovskite films using TO or without adding an extra solvent, respectively. The interaction between the PbI2-DMSO-CH3NH3I intermediate phase and the additional solvent was discussed. Furthermore, the influence of the annealing temperature on the absorber film formation, morphology, and crystalline structure was investigated and correlated with the photovoltaic performance. Highly efficient, simple, and stable HTM-free solar cells with a PCE of 11.44 % were prepared utilizing the optimum perovskite absorbers annealed at 120 °C.

10.
ACS Appl Mater Interfaces ; 6(20): 17454-62, 2014 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-25269703

RESUMEN

We present for the first time the synthesis of Eu(3+)-doped ß-phase sodium gadolinium fluoride (NaGdF4:Eu) nanocrystals (NCs) using a hydrothermal method and the application of down conversion (DC) NaGdF4:Eu NCs to efficient dye-sensitized solar cells (DSSCs). The as-prepared NaGdF4:Eu(3+) NCs were characterized by X-ray diffraction, photoluminescence spectrometry, and scanning and transmission electron microscopy. DC layers consisting of poly(methyl methacrylate) (PMMA) doped with luminescent NaGdF4:Eu(3+) were prepared and attached onto the back of a prefabricated TiO2 anode to form a more efficient DSSC, compared with a device based on a pure TiO2 electrode. The influences of both doped and undoped NaGdF4 NC layers on the photovoltaic devices were compared and evaluated by the measurement of the device's incident-photon-to-current efficiency (IPCE). An obvious increase in IPCE was observed when the DC layer was added in the device. As the down-converted photons can be reabsorbed within DSSCs to generate photocurrent, the DSSC with a 100 nm thick NaGdF4:Eu(3+) DC-PMMA layer improved photoelectric conversion efficiency by 4.5% relative to the uncoated solar cell. The experiments conclude that NaGdF4:Eu(3+) nanocrystals mainly act as luminescent DC centers and light scatterers in the ultraviolet and visible domains, respectively, for enhancing the spectral response of the device in the measured spectral regime.

11.
Food Chem ; 135(3): 985-92, 2012 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-22953814

RESUMEN

The effects of electrolysed water (EW) and EW in combination with 1-methylcyclopropene (EW/MCP) on flesh discolouration of Nanhui peaches (Prunus persica (L.) Batsch, cv. Nanhui) were examined during storage at 2°C. Changes in flesh colour, ethylene production, membrane permeability, malondialdehyde (MDA), total phenolic contents and the activities of polyphenol oxidase (PPO) and peroxidase (POD) were assayed periodically after harvest and during 44days of storage. The internal morphological characteristics of Nanhui peaches were monitored using magnetic resonance imaging (MRI) at the beginning and end of storage. These data revealed that the EW/MCP treatment is more effective than the EW treatment for decreasing ethylene production and maintaining fruit cell membrane integrity, delaying increases in MDA and total phenolic contents, and lessening changes in PPO and POD activities and the internal morphology of peaches. Each of these effects contributes to suppressing flesh discolouration and maintaining the quality of Nanhui peaches during storage.


Asunto(s)
Ciclopropanos/farmacología , Conservación de Alimentos/métodos , Conservantes de Alimentos/farmacología , Frutas/química , Prunus/química , Agua/farmacología , Color , Electrólisis , Almacenamiento de Alimentos , Frutas/efectos de los fármacos , Prunus/efectos de los fármacos , Agua/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...