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PURPOSE: We investigated the connectivity of neural signals from movement-related cortical areas to the primary motor area (M1) in the hemisphere contralateral to the movement side during the period of movement-related magnetic fields before movement. MATERIALS AND METHODS: Participants were 13 healthy adults, and nerual signals were recorded using magnetoencephalography. Spontaneous extension of the right wrist was performed at the participant's own pace and following a visual cue in internal (IC) and external (EC) cue tasks. The connectivity of neural signals to M1 from each movement-related motor area was assessed by Granger causality analysis (GCA). The GCA was performed on the neural activity elicited in a frequency band between 7.8 and 46.9 Hz during the pre-movement periods, which occurred durng the readiness field (RF) and the negative slope prime (NSp). F-values, as connectivity values obtained by GCA, were compared between the EC and IC cue tasks. RESULTS: For NSp periods, the connectivity of neural signals from the left superior frontal area (SF-L) to M1 was dominant in the IC task, whereas that from the left superior parietal area (SP-L) to M1 was dominant in the EC task. The F value in the GCA from SP-L to M1 was greater in the EC task during RF than in the IC task during equivalent periods. CONSLUSIONS: In the present study, there were differences in the connectivity of neural signals to M1 between IC and EC tasks. The present results suggested that the pattern of pre-movement neural activity that resulted in a movement was not uniform but differed between movement tasks just before the movement.
Movement-related cortical magnetic fields were assessed with Granger causality analysisConnectivity of neural signals to M1 was different between internal and external cue tasks.Connectivity of neural signals from the frontal area was dominant to M1 in the internal cue task.Connectivity of neural signals to M1 from the parietal area was observed in the external cue task.
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Accumulating evidence from anatomical and neuroimaging studies suggests that the cerebellum is engaged in a variety of motor and cognitive tasks. Given its various functions, a key question is whether the cerebellum also plays an important role in the brain's integrative functions. Here, we hypothesize the existence of connector regions, also known as connector hubs, where multiple resting state networks converged in the cerebellum. To verify this, we employed a recently developed voxel-level network measure called functional connectivity overlap ratio (FCOR), which could be used to quantify the spatial extent of a region's connection to several large-scale cortical networks. Using resting state functional MRI data from 101 healthy participants, cerebellar FCOR maps were constructed and used to identify the locations of connector hubs in the cerebellum. Results showed that a number of cerebellar regions exhibited strong connectivity with multiple functional networks, verifying our hypothesis. These highly connected regions were located in the posterior cerebellum, especially in lobules VI, VII, and IX, and mainly connected to the core neurocognitive networks such as default mode and executive control networks. Regions associated with the sensorimotor network were also localized in lobule V, VI, and VIII, albeit in small clusters. These cerebellar connector hubs may play an essential role in the processing of information across the core neurocognitive networks.
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Cerebelo , Imagen por Resonancia Magnética , Cerebelo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética/métodos , Vías Nerviosas , NeuroimagenRESUMEN
Conscious perception of a near-threshold (NT) stimulus is characterized by the pre- and post-stimulus brain state. However, the power of pre-stimulus neural oscillations and strength of post-stimulus cortical activity that lead to conscious perception have rarely been examined in individual cortical areas. This is because most previous electro- and magnetoencephalography (EEG and MEG, respectively) studies involved scalp- and sensor-level analyses. Therefore, we recorded MEG during a continuous NT somatosensory stimulus detection task and applied the reconstructed source data in order to identify cortical areas where the post-stimulus cortical activity and pre-stimulus alpha oscillation predict the conscious perception of NT somatosensory stimuli. We found that the somatosensory hierarchical processing areas, prefrontal areas and cortical areas belonging to the default mode network showed stronger cortical activity for consciously perceived trials in the post-stimulus period, but the cortical activity in primary somatosensory area (SI) is independent of conscious perception during the early stage of NT stimulus processing. In addition, we revealed that the pre-stimulus alpha oscillation only in SI is predictive of conscious perception. These findings suggest that the bottom-up stream of somatosensory information flow following SI and pre-stimulus alpha activity fluctuation in SI as a top-down modulation are crucial constituents of conscious perception.
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Electroencefalografía , Corteza Somatosensorial , Mapeo Encefálico , Estado de Conciencia , MagnetoencefalografíaRESUMEN
Neuroimaging studies have shown that the brain is functionally organized into several large-scale brain networks. Within these networks are regions that are widely connected to several other regions within and/or outside the network. Regions that connect to several other networks, known as connector hubs, are believed to be crucial for information transfer and between-network communication within the brain. To identify regions with high between-network connectivity at the voxel level, we introduced a novel metric called functional connectivity overlap ratio (FCOR), which quantifies the spatial extent of a region's connection to a given network. Using resting state functional magnetic resonance imaging data, FCOR maps were generated for several well-known large-scale resting state networks (RSNs) and used to examine the relevant associations among different RSNs, identify connector hub regions in the cerebral cortex, and elucidate the hierarchical functional organization of the brain. Constructed FCOR maps revealed a strong association among the core neurocognitive networks (default mode, salience, and executive control) as well as among primary processing networks (sensorimotor, auditory, and visual). Prominent connector hubs were identified in the bilateral middle frontal gyrus, posterior cingulate, lateral parietal, middle temporal, dorsal anterior cingulate, and anterior insula, among others, regions mostly associated with the core neurocognitive networks. Finally, clustering the whole brain using FCOR features yielded a topological organization that arranges brain regions into a hierarchy of information processing systems with the primary processing systems at one end and the heteromodal systems comprising connector hubs at the other end.
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Encéfalo/fisiología , Red Nerviosa/fisiología , Vías Nerviosas/fisiología , Adulto , Corteza Cerebral/fisiología , Función Ejecutiva , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Adulto JovenRESUMEN
White matter (WM) fiber bundles change dynamically with age. These changes could be driven by alterations in axonal diameter, axonal density, and myelin content. In this study, we applied a novel fixel-based analysis (FBA) framework to examine these changes throughout the adult lifespan. Using diffusion-weighted images from a cohort of 293 healthy volunteers (89 males/204 females) from ages 21 to 86 years old, we performed FBA to analyze age-related changes in microscopic fiber density (FD) and macroscopic fiber morphology (fiber cross section [FC]). Our results showed significant and widespread age-related alterations in FD and FC across the whole brain. Interestingly, some fiber bundles such as the anterior thalamic radiation, corpus callosum, and superior longitudinal fasciculus only showed significant negative relationship with age in FD values, but not in FC. On the other hand, some segments of the cerebello-thalamo-cortical pathway only showed significant negative relationship with age in FC, but not in FD. Analysis at the tract-level also showed that major fiber tract groups predominantly distributed in the frontal lobe (cingulum, forceps minor) exhibited greater vulnerability to the aging process than the others. Differences in FC and the combined measure of FD and cross section values observed between sexes were mostly driven by differences in brain sizes although male participants tended to exhibit steeper negative linear relationship with age in FD as compared to female participants. Overall, these findings provide further insights into the structural changes the brain's WM undergoes due to the aging process.
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Envejecimiento/fisiología , Imagen de Difusión por Resonancia Magnética , Desarrollo Humano/fisiología , Fibras Nerviosas Mielínicas/fisiología , Sustancia Blanca/anatomía & histología , Sustancia Blanca/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Imagen de Difusión por Resonancia Magnética/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Vías Nerviosas/anatomía & histología , Vías Nerviosas/diagnóstico por imagen , Factores Sexuales , Sustancia Blanca/diagnóstico por imagen , Adulto JovenRESUMEN
This study aims to elucidate age-related intrinsic brain volume changes over the adult lifespan using an unbiased data-driven structural brain parcellation. Anatomical brain images from a cohort of 293 healthy volunteers ranging in age from 21 to 86 years were analyzed using independent component analysis (ICA). ICA-based parcellation identified 192 component images, of which 174 (90.6%) showed a significant negative correlation with age and with some components being more vulnerable to aging effects than others. Seven components demonstrated a convex slope with aging; 3 components had an inverted U-shaped trajectory, and 4 had a U-shaped trajectory. Linear combination of 86 components provided reliable prediction of chronological age with a mean absolute prediction error of approximately 7.2 years. Structural co-variation analysis showed strong interhemispheric, short-distance positive correlations and long-distance, inter-lobar negative correlations. Estimated network measures either exhibited a U- or an inverted U-shaped relationship with age, with the vertex occurring at approximately 45-50 years. Overall, these findings could contribute to our knowledge about healthy brain aging and could help provide a framework to distinguish the normal aging processes from that associated with age-related neurodegenerative diseases.
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Envejecimiento/fisiología , Encéfalo/anatomía & histología , Sustancia Gris/anatomía & histología , Desarrollo Humano/fisiología , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Encéfalo/diagnóstico por imagen , Femenino , Sustancia Gris/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Neural connectivity was measured during motor imagery (MI) and motor execution (ME) using magnetoencephalography in nine healthy subjects, MI, and at rest. Lower coherence values during ME and MI between sensorimotor areas than at rest, and lower values during MI between the left supplementary motor area and inferior frontal gyrus than ME suggested the sensorimotor network of MI functioned with similar connectivity to ME and that the inhibitory activity functioned continuously during MI, respectively.
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Imaginación , Magnetoencefalografía , Actividad Motora/fisiología , Red Nerviosa/fisiología , Corteza Sensoriomotora/fisiología , Adulto , Mapeo Encefálico , Dedos/fisiología , Humanos , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/diagnóstico por imagen , Adulto JovenRESUMEN
Visual dysfunction can be caused by several abnormalities, including dysfunctions in the visual cortex and retina. Our aim was to investigate changes in visual evoked brain responses in the primary visual cortex associated with Parkinson's disease (PD). Sixteen healthy control subjects and ten patients with PD participated in this study. We assessed the visual evoked magnetic field (VEF) using magnetoencephalography (MEG). Checkerboard pattern reversal (CPR) and monotonous grating pattern (MGP) stimulations were used. Magnetic resonance imaging (MRI) was performed to analyze brain volume and generate a tractogram. Cognitive and olfactory function, and Unified Parkinson's Disease Rating Scale (UPDRS) scores were evaluated in patients with PD. Four components of the VEF (1M, 2M, 3M, 4M) were observed following stimulation. For both stimuli, results from the 1M and 2M components were significantly greater and the latency of the 1M component was increased markedly in the PD group compared with the healthy control group. In the PD group, 1M latency correlated with the UPDRS score of 1 for both stimuli, and a correlation was observed between olfactory function and the UPDRS score of 3 for the CPR stimulation alone. We suggest that the conduction delay observed following visual stimulation occurs peripherally rather than in the primary visual cortex. Degeneration of selective elements of the visual system in the retina, possibly midget cells, may be involved.
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Potenciales Evocados Visuales/fisiología , Enfermedad de Parkinson/fisiopatología , Retina/fisiopatología , Anciano , Encéfalo/metabolismo , Encéfalo/fisiología , Cognición/efectos de la radiación , Femenino , Humanos , Magnetoencefalografía , Masculino , Persona de Mediana EdadRESUMEN
INTRODUCTION: Observing another person's action influences the execution of one's own action via the mirror neuron system. However, the ability to control the effect of such action observation on one's voluntary action has not been investigated. The aim of this study was to elucidate the influence of observing another's action on own voluntary movement in patients with schizophrenia. METHODS: Fifteen patients with schizophrenia and 15 healthy age-matched controls participated in this study. Subjects were asked to perform a gripping task at 50% of their maximal voluntary force (MVF), whereas simultaneously watching others performed the same task with a different grip force (0%, 50% and 100% MVF). RESULTS: The healthy controls applied a constant grip force under each condition. In patients with schizophrenia, the grip force was significantly reduced during viewing the gripping of others at 50% MVF compared to during viewing other's gripping at 0% and 100% MVF. The score of the Brief Psychiatric Rating Scale (BPRS) and the Scale for the Assessment of Positive Symptoms were correlated with the fluctuation in grip force among the action observation conditions. CONCLUSION: Patients with schizophrenia might have difficulty controlling the influence of action observation on self-generated performance.
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Neuronas Espejo/fisiología , Desempeño Psicomotor/fisiología , Esquizofrenia/fisiopatología , Adulto , Femenino , Fuerza de la Mano/fisiología , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Objectives: To elucidate the functional characteristics of the brain in the presence of chronic pain using electroencephalography (EEG), with a focus on the dynamics of neural excitation and inhibition. Methods: Resting-state EEG was performed in: 17 patients with complex regional pain syndrome (CRPS) who exhibited chronic pain higher than 20 on the visual analogue scale (VAS), 6 patients with reduced CRPS symptoms and chronic pain less than 20 on VAS, and healthy age-matched controls. For the analysis, 50 s of electroencephalogram (EEG) signals were extracted from EEG recordings during wakefulness and rest with eyes closed. The envelope of the alpha frequency band was calculated by examining the positive and negative accelerations of the envelope oscillation, ratio of positive (Ap) to negative (An) accelerations (Ap-An ratio), and mean amplitude of the envelope. Comparisons were made between patients and controls, and correlations between these EEG measures and the subjective pain VAS were evaluated.Significant differences in the value of Ap, An and Ap-An ratio were observed at temporal and central electrodes between patients with pain symptoms and controls. Those with reduced CRPS symptoms exhibited a distinct Ap-An ratio at the majority of electrodes when compared with those exhibiting chronic pain. Conclusions: Distinct patterns in alpha wave envelope dynamics, reflecting excitatory and inhibitory activities, were associated with chronic pain in patients with CRPS. The pain-relieved state of CRPS suggested that a new balance of activities was established. This relationship indicated a potential association between altered alpha oscillation characteristics and the subjective experience of pain. Significance: This study introduces a novel method for analyzing alpha oscillation envelopes, providing new insights into the neural pathophysiology of chronic pain in CRPS patients. This approach has the potential to enhance our understanding of the alterations in brain function that occur under chronic pain conditions.
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Alpha waves, one of the major components of resting and awake cortical activity in human electroencephalography (EEG), are known to show waxing and waning, but this phenomenon has rarely been analyzed. In the present study, we analyzed this phenomenon from the viewpoint of excitation and inhibition. The alpha wave envelope was subjected to secondary differentiation. This gave the positive (acceleration positive, Ap) and negative (acceleration negative, An) values of acceleration and their ratio (Ap-An ratio) at each sampling point of the envelope signals for 60 seconds. This analysis was performed on 36 participants with Alzheimer's disease (AD), 23 with frontotemporal dementia (FTD) and 29 age-matched healthy participants (NC) whose data were provided as open datasets. The mean values of the Ap-An ratio for 60 seconds at each EEG electrode were compared between the NC and AD/FTD groups. The AD (1.41 ±0.01 (SD)) and FTD (1.40 ±0.02) groups showed a larger Ap-An ratio than the NC group (1.38 ±0.02, p<0.05). A significant correlation between the envelope amplitude of alpha activity and the Ap-An ratio was observed at most electrodes in the NC group (Pearson's correlation coefficient, r = -0.92 ±0.15, mean for all electrodes), whereas the correlation was disrupted in AD (-0.09 ±0.21, p<0.05) and disrupted in the frontal region in the FTD group. The present method analyzed the envelope of alpha waves from a new perspective, that of excitation and inhibition, and it could detect properties of the EEG, Ap-An ratio, that have not been revealed by existing methods. The present study proposed a new method to analyze the alpha activity envelope in electroencephalography, which could be related to excitatory and inhibitory neural activity.
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Ritmo alfa , Enfermedad de Alzheimer , Electroencefalografía , Demencia Frontotemporal , Humanos , Masculino , Femenino , Electroencefalografía/métodos , Anciano , Enfermedad de Alzheimer/fisiopatología , Ritmo alfa/fisiología , Demencia Frontotemporal/fisiopatología , Persona de Mediana Edad , Estudios de Casos y ControlesRESUMEN
INTRODUCTION: Connector hubs are specialized brain regions that connect multiple brain networks and therefore have the potential to affect the functions of multiple systems. This study aims to examine the involvement of connector hub regions in essential tremor. METHODS: We examined whole-brain functional connectivity alterations across multiple brain networks in 27 patients with essential tremor and 27 age- and sex-matched healthy controls to identify affected hub regions using a network metric called functional connectivity overlap ratio estimated from resting-state functional MRI. We also evaluated the relationships of affected hubs with cognitive and tremor scores in all patients and with motor function improvement scores in 15 patients who underwent postoperative follow-up evaluations after focused ultrasound thalamotomy. RESULTS: We have identified affected connector hubs in the cerebellum and thalamus. Specifically, the dentate nucleus in the cerebellum and the dorsomedial thalamus exhibited more extensive connections with the sensorimotor network in patients. Moreover, the connections of the thalamic pulvinar with the visual network were also significantly widespread in the patient group. The connections of these connector hub regions with cognitive networks were negatively associated (FDR q < 0.05) with cognitive, tremor, and motor function improvement scores. CONCLUSION: In patients with essential tremor, connector hub regions within the cerebellum and thalamus exhibited widespread functional connections with sensorimotor and visual networks, leading to alternative pathways outside the classical tremor axis. Their connections with cognitive networks also affect patients' cognitive function.
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Temblor Esencial , Humanos , Temblor Esencial/cirugía , Temblor , Imagen por Resonancia Magnética , Tálamo/diagnóstico por imagen , Tálamo/cirugía , Cerebelo/diagnóstico por imagen , CogniciónRESUMEN
This work aimed to investigate the involvement of the thalamic nuclei in mesial temporal lobe epilepsy (MTLE) and identify the influence of interictal epileptic discharges on the neural basis of memory processing by evaluating the functional connectivity (FC) between the thalamic nuclei and default mode network-related area (DMNRA) using magnetoencephalography. Preoperative datasets of nine patients with MTLE with seizure-free status after surgery and those of nine healthy controls were analyzed. The FC between the thalamic nuclei (anterior nucleus [ANT], mediodorsal nucleus [MD], intralaminar nuclei [IL]), hippocampus, and DMNRA was examined for each of the resting, pre-spike, spike, and post-spike periods in the delta to ripple bands using magnetoencephalography. The FC between the ANT, MD, hippocampus, and medial prefrontal cortex increased in the gamma to ripple bands, whereas the FC between the ANT, IL, and DMNRA decreased in the delta to beta bands, compared with that of the healthy controls at rest. Compared with the rest period, the pre-spike period had significantly decreased FC between the ANT, MD, and DMNRA in the ripple band. Different FC changes between the thalamic nuclei, hippocampus, and DMNRA of specific connections in a particular band may reflect impairment or compensation in the memory processes.
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Epilepsia del Lóbulo Temporal , Humanos , Epilepsia del Lóbulo Temporal/diagnóstico por imagen , Magnetoencefalografía , Red en Modo Predeterminado , Núcleos Talámicos , MemoriaRESUMEN
This prospective study investigated psychological factors affecting wound healing in patients with peripheral arterial disease (PAD). Fifty patients with PAD in a local hospital were enrolled. The Geriatric Depression Scale short version, Type-D scale 14, Medical Outcome Study 36-Item Short-Form Health Survey (SF-36), Functional Independence Measure, Self-efficacy for Managing Chronic Disease Scale, Barriers Self-Efficacy Scale, and Mini Nutritional Assessment were applied to assess physical and psychological factors. Wound occurrence and healing were evaluated at 6 months after discharge, and 34 and 30 patients could be followed, respectively. The patient group with wound occurrence showed poorer mental component score (MCS) and better role/social component score (RCS) category scores of SF-36, and a higher stage in the Fontaine classification, than those without wound occurrence. On comparing Fontaine classification-matched subgroups, patients with wound occurrence showed poorer general health factor and MCS and better RCS of SF-36 than those without wound occurrence. Logistic analysis showed that MCS and RCS predicted wound occurrence and needs for local medical treatment, respectively. Among the psychological factors tested, MCS was a major factor associated with wound occurrence in the present study, with wide variation in clinical conditions and factors associated with PAD. Psychological factors were important as biological, physical, and social factors for patients with PAD during the long-term follow-up period, and an appropriate battery to evaluate psychological factors focused on patients with PAD should be developed.
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Pierna , Enfermedad Arterial Periférica , Anciano , Encuestas Epidemiológicas , Humanos , Evaluación de Resultado en la Atención de Salud , Enfermedad Arterial Periférica/diagnóstico , Enfermedad Arterial Periférica/epidemiología , Estudios ProspectivosRESUMEN
The aging brain undergoes structural changes even in very healthy individuals. Quantifying these changes could help disentangle pathologic changes from those associated with the normal human aging process. Using longitudinal magnetic resonance imaging (MRI) data from 227 carefully selected healthy human cohort with age ranging from 50 to 80 years old at baseline scan, we quantified age-related volumetric changes in the brain of healthy human older adults. Longitudinally, the rates of tissue loss in total gray matter (GM) and white matter (WM) were 2497.5 and 2579.8 mm3 per year, respectively. Across the whole brain, the rates of GM decline varied with regions in the frontal and parietal lobes having faster rates of decline, whereas some regions in the occipital and temporal lobes appeared relatively preserved. In contrast, cross-sectional changes were mainly observed in the temporal-occipital regions. Similar longitudinal atrophic changes were also observed in subcortical regions including thalamus, hippocampus, putamen, and caudate, whereas the pallidum showed an increasing volume with age. Overall, regions maturing late in development (frontal, parietal) are more vulnerable to longitudinal decline, whereas those that fully mature in the early stage (temporal, occipital) are mainly affected by cross-sectional changes in healthy older cohort. This may suggest that, for a successful healthy aging, the former needs to be maximally developed at an earlier age to compensate for the longitudinal decline later in life and the latter to remain relatively preserved even in old age, consistent with both concepts of reserve and brain maintenance.
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Envejecimiento , Encéfalo , Anciano , Anciano de 80 o más Años , Envejecimiento/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Estudios Transversales , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética/métodos , Persona de Mediana EdadRESUMEN
To analyze complex scenes efficiently, the human visual system performs perceptual groupings based on various features (e.g., color and motion) of the visual elements in a scene. Although previous studies demonstrated that such groupings can be based on a single feature (e.g., either color or motion information), here we show that the visual system also performs scene analyses based on a combination of two features. We presented subjects with a mixture of red and green dots moving in various directions. Although the pairings between color and motion information were variable across the dots (e.g., one red dot moved upward while another moved rightward), subjects' perceptions of the color-motion pairings were significantly biased when the randomly paired dots were flanked by additional dots with consistent color-motion pairings. These results indicate that the visual system resolves local ambiguities in color-motion pairings using unambiguous pairings in surrounds, demonstrating a new type of scene analysis based on the combination of two featural cues.
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Percepción de Color/fisiología , Percepción de Movimiento/fisiología , Reconocimiento Visual de Modelos/fisiología , Adulto , Señales (Psicología) , Femenino , Humanos , Masculino , Estimulación Luminosa/métodos , Adulto JovenRESUMEN
We investigated differences in the cognitive/attention process following visual stimulation of the left and right hemi-visual fields. Visual P300 was recorded in 31 healthy right-handed subjects following target and non-target stimuli presented randomly in both visual fields. Counting and reaction time (RT) tasks using the left and right hands were performed. The P300 amplitude was significantly smaller in the RT session using the left hand. The amplitude was larger following target stimulation in the left hemi-visual field in the RT sessions using both the left and right hands. The P300 latency did not change in each stimulus condition and session, but the RT was longer for the target in the right hemi-visual field in the RT session using the left hand. We showed asymmetry of P300 response following each hemi-visual field in healthy subjects, and visual stimuli in the left hemi-visual field were dominantly processed.
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Potenciales Relacionados con Evento P300/fisiología , Estimulación Luminosa , Campos Visuales/fisiología , Adulto , Cognición/fisiología , Electroencefalografía , Femenino , Lateralidad Funcional/fisiología , Humanos , Masculino , Tiempo de Reacción/fisiologíaRESUMEN
Background: Neural connectivity in brain has been known as indicators for neural function and recovery of brain. Although previous studies reported that neural connectivity predicted the recovery of upper limb function after stroke, the relationship between neural connectivity and lower limb function has not been clear.Objectives: To clarify whether functional connectivity (FC) assessed by electroencephalographiy (EEG) with five electrodes placed on motor-related areas could be related to the functional motor recovery of the lower limbs in patients after stroke.Methods: Twenty-four patients with stroke during the recovery phase were recruited. Motor function of the lower limbs was assessed using Fugl-Meyer Assessment lower limb section (FMAL). EEG signals were recorded by five electrodes (C3, C4, FC3, FC4, and FCz) at rest and during ankle movement. Amplitude envelope correlations, as values for FC, were calculated in α (8-12 Hz), ß (13-30 Hz), low-ß (13-19 Hz), and high-ß (20-30 Hz) frequency bands. The predictive regression equation of the FMAL score in the eighth week after stroke (8 W) was created by FCs in the fourth week (4 W).Results: The higher intra-hemispheric FC in both hemispheres in the resting state and during the ankle movement at 4 W was related to a higher lower limb function at 8 W. Additionally, the higher inter-hemispheric FC between M1 on both sides during the ankle movement was related to a higher function recovery.Conclusions: The intra- and inter-hemispheric FC among motor-related areas at 4 W after stroke might be related to the functional recovery of the lower limbs at 8 W.
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Corteza Motora , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Electroencefalografía , Humanos , Extremidad Inferior , Recuperación de la FunciónRESUMEN
Quantitative objective measurement of chronic pain is important. We elucidated chronic pain-related cortical neural activity and neural connectivity among pain-related brain regions in complex regional pain syndrome (CRPS). Resting-state magnetoencephalography recordings were performed. Cortical current density and neural connectivity, revealed by amplitude envelope correlation (AEC), were estimated on standardized brain magnetic resonance imaging. Intra-experiment pain was assessed subjectively using a visual analogue scale (VAS). The correlation between current density and VAS scores was calculated for the occipital areas and pain-related cortices. Current density in the primary (SI) and secondary (SII) somatosensory cortex and precuneus in both hemispheres was negatively correlated with the pain VAS score. The AEC and VAS values were significantly correlated for the SII and the precuneus and for the SII and insular cortex in the alpha frequency band in the right hemisphere. In the theta frequency band, the AEC and VAS values correlated for the SII and posterior cingulate cortex in the right hemisphere. Our results suggested that disruption of pain processes and functions in the default mode network occurs in CRPS. Our method targeting the neural mechanism of pain has the potential to offer a clinically objective means of evaluating it.
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Purpose: Maintenance of cognitive performance is important for healthy aging. This study aims to elucidate the relationship between brain networks and cognitive function in subjects maintaining relatively good cognitive performance. Methods: A total of 120 subjects, with equal number of participants from each age group between 20 and 70 years, were included in this study. Only participants with Addenbrooke's Cognitive Examination - Revised (ACE-R) total score greater than 83 were included. Anatomical T1-weighted MR images and resting-state functional MR images (rsfMRIs) were taken from all participants using a 3-tesla MRI scanner. After preprocessing, several factors associated with age including the ACE-R total score, scores of five domains, sub-scores of ACE-R, and brain volumes were tested. Morphometric changes associated with age were analyzed using voxel based morphometry (VBM) and changes in resting state networks (RSNs) were examined using dual regression analysis. Results: Significant negative correlations with age were seen in the total gray matter volume (GMV, r = -0.58), and in the memory, attention, and visuospatial domains. Among the different sub-scores, the score of the delayed recall (DR) showed the highest negative correlation with age (r = -0.55, p < 0.001). In VBM analysis, widespread regions demonstrated negative correlation with age, but none with any of the cognitive scores. Quadratic approximations of cognitive scores as functions of age showed relatively delayed decline compared to total GMV loss. In dual regression analysis, some cognitive networks, including the dorsal default mode network, the lateral dorsal attention network, the right / left executive control network, the posterior salience network, and the language network, did not demonstrate negative correlation with age. Some regions in the sensorimotor networks showed positive correlation with the DR, memory, and fluency scores. Conclusion: Some domains of the cognitive test did not correlate with age, and even the highly correlated sub-scores such as the DR score, showed delayed decline compared to the loss of total GMV. Some RSNs, especially involving cognitive control regions, were relatively maintained with age. Furthermore, the scores of memory, fluency, and the DR were correlated with the within-network functional connectivity values of the sensorimotor network, which supported the importance of exercise for maintenance of cognition.