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Previous research has shown that action effects of self-generated movements are internally predicted before outcome feedback becomes available. To test whether these sensorimotor predictions are used to facilitate visual information uptake for feedback processing, we measured eye movements during the execution of a goal-directed throwing task. Participants could fully observe the effects of their throwing actions (ball trajectory and either hitting or missing a target) in most of the trials. In a portion of the trials, the ball trajectory was not visible, and participants only received static information about the outcome. We observed a large proportion of predictive saccades, shifting gaze toward the goal region before the ball arrived and outcome feedback became available. Fixation locations after predictive saccades systematically covaried with future ball positions in trials with continuous ball flight information, but notably also in trials with static outcome feedback and only efferent and proprioceptive information about the movement that could be used for predictions. Fixation durations at the chosen positions after feedback onset were modulated by action outcome (longer durations for misses than for hits) and outcome uncertainty (longer durations for narrow vs. clear outcomes). Combining both effects, durations were longest for narrow errors and shortest for clear hits, indicating that the chosen locations offer informational value for feedback processing. Thus, humans are able to use sensorimotor predictions to direct their gaze toward task-relevant feedback locations. Outcome-dependent saccade latency differences (miss vs. hit) indicate that also predictive valuation processes are involved in planning predictive saccades.NEW & NOTEWORTHY We elucidate the potential benefits of sensorimotor predictions, focusing on how the system actually uses this information to optimize feedback processing in goal-directed actions. Sensorimotor information is used to predict spatial parameters of movement outcomes, guiding predictive saccades toward future action effects. Saccade latencies and fixation durations are modulated by outcome quality, indicating that predictive valuation processes are considered and that the locations chosen are of high informational value for feedback processing.
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Fixação Ocular , Objetivos , Desempenho Psicomotor , Movimentos Sacádicos , Humanos , Masculino , Feminino , Adulto , Desempenho Psicomotor/fisiologia , Movimentos Sacádicos/fisiologia , Fixação Ocular/fisiologia , Adulto Jovem , Retroalimentação Sensorial/fisiologiaRESUMO
When memorizing an integrated object such as a Kanizsa figure, the completion of parts into a coherent whole is attained by grouping processes which render a whole-object representation in visual working memory (VWM). The present study measured event-related potentials (ERPs) and oscillatory amplitudes to track these processes of encoding and representing multiple features of an object in VWM. To this end, a change detection task was performed, which required observers to memorize both the orientations and colors of six "pacman" items while inducing configurations of the pacmen that systematically varied in terms of their grouping strength. The results revealed an effect of object configuration in VWM despite physically constant visual input: change detection for both orientation and color features was more accurate with increased grouping strength. At the electrophysiological level, the lateralized ERPs and alpha activity mirrored this behavioral pattern. Perception of the orientation features gave rise to the encoding of a grouped object as reflected by the amplitudes of the Ppc. The grouped object structure, in turn, modulated attention to both orientation and color features as indicated by the enhanced N1pc and N2pc. Finally, during item retention, the representation of individual objects and the concurrent allocation of attention to these memorized objects were modulated by grouping, as reflected by variations in the CDA amplitude and a concurrent lateralized alpha suppression, respectively. These results indicate that memorizing multiple features of grouped, to-be-integrated objects involves multiple, sequential stages of processing, providing support for a hierarchical model of object representations in VWM.
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Ritmo alfa , Eletroencefalografia , Potenciais Evocados , Memória de Curto Prazo , Humanos , Memória de Curto Prazo/fisiologia , Masculino , Feminino , Adulto Jovem , Ritmo alfa/fisiologia , Potenciais Evocados/fisiologia , Adulto , Percepção Visual/fisiologia , Atenção/fisiologia , Estimulação Luminosa , Reconhecimento Visual de Modelos/fisiologiaRESUMO
PURPOSE: Patients with hypothalamic pathology often develop hypothalamic obesity, causing severe metabolic alterations resulting in increased morbidity and mortality. Treatments for hypothalamic obesity have not proven very effective, although the glucagon-like peptide-1 receptor agonist semaglutide has been shown to have positive effects. We examined semaglutide's effect on weight loss in a sample of patients with hypothalamic obesity. METHODS: Four female patients with hypothalamic obesity resulting from treatment of craniopharyngiomas were treated with semaglutide for six months. Whole Body Dual-energy x-ray absorptiometry scans were performed, and blood samples drawn at baseline and after six months. Semaglutide dosages were increased monthly along with tracking of body weight and eating behavior (Three Factor Eating Questionnaire, TFEQ-R18). RESULTS: BMI was reduced in all cases, with an average of 7.9 BMI (range: 6.7 to 10.1) corresponding to a weight loss of 17.0% (range: 11.3-22.4%) or 20.2 kg (range 16.2 kg to 23.4 kg). We found a comparable reduction in total fat mass (17.2%, p = 0.006) and lean mass (16.0%, p = 0.05), whereas bone mass was unchanged (2.6%, p = 0.12). All cases reported an increase in energy levels, improved mobility and physical activity. Unfavorable eating behaviors were reduced after 1 month of treatment (emotional eating - 41 points, p = 0.02, uncontrolled eating - 23 points, p = 0.11). HbA1c and total cholesterol were significantly reduced (p = 0.014 for both). CONCLUSION: Semaglutide is a promising and safe treatment option for HO, that improves eating behavior, reduces weight, and improves metabolic markers.
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Some studies have suggested that emotion-associated features might influence attentional capture. However, demonstrating valence-dependent distractor interference has proven challenging, possibly due to the neglect of individuals' color-valence preferences in standard, averaged reaction-time (RT) measures. To address this, we investigated valence-driven attentional-capture using an association phase in which emotionally neutral vs. positive-feedback photographs were paired with two alternative target colors, red vs. green. This was followed by a test phase requiring participants to search for a pop-out shape target in the presence or absence of an emotion-associated color. In Experiments 1 and 2, this color could only appear in a distractor, while in Experiment 3, it appeared in the target. Analyzing the standard, averaged RT measures, we found no significant valence association or valence-modulated attentional capture. However, correlational analyses revealed a positive relationship between individual participants' color-valence preference during the association phase and their valence-based effect during the test phase. Moreover, most individuals favored red over green in the association phase, leading to marked color-related asymmetries in the average measures. Crucially, the presence of the valence-preferred color anywhere in the test display facilitated RTs. This effect persisted even when the color appeared in one of the distractors (Experiments 1 and 2), at variance with this distractor capturing attention. These findings suggest that task-irrelevant valence-preferred color signals were registered pre-attentively and boosted performance, likely by raising the general (non-spatial) alertness level. However, these signals were likely kept out of attentional-priority computation to prevent inadvertent attentional capture.
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Atenção , Emoções , Humanos , Tempo de Reação , Percepção de CoresRESUMO
Redundant combination of target features from separable dimensions can expedite visual search. The dimension-weighting account explains these "redundancy gains" by assuming that the attention-guiding priority map integrates the feature-contrast signals generated by targets within the respective dimensions. The present study investigated whether this hierarchical architecture is sufficient to explain the gains accruing from redundant targets defined by features in different modalities, or whether an additional level of modality-specific priority coding is necessary, as postulated by the modality-weighting account (MWA). To address this, we had observers perform a visuo-tactile search task in which targets popped out by a visual feature (color or shape) or a tactile feature (vibro-tactile frequency) as well as any combination of these features. The RT gains turned out larger for visuo-tactile versus visual redundant targets, as predicted by the MWA. In addition, we analyzed two lateralized event-related EEG components: the posterior (PCN) and central (CCN) contralateral negativities, which are associated with visual and tactile attentional selection, respectively. The CCN proved to be a stable somatosensory component, unaffected by cross-modal redundancies. In contrast, the PCN was sensitive to cross-modal redundancies, evidenced by earlier onsets and higher amplitudes, which could not be explained by linear superposition of the earlier CCN onto the later PCN. Moreover, linear mixed-effect modeling of the PCN amplitude and timing parameters accounted for approximately 25% of the behavioral RT variance. Together, these behavioral and PCN effects support the hierarchy of priority-signal computation assumed by the MWA.
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Atenção , Tato , HumanosRESUMO
Visual working memory (VWM) is limited in capacity, though memorizing meaningful objects may refine this limitation. However, meaningful and meaningless stimuli typically differ perceptually, and objects' associations with meaning are usually already established outside the laboratory, potentially confounding experimental findings. Here, in two experiments with young adults (N = 45 and N = 20), we controlled for these influences by having observers actively learn associations of (for them) initially meaningless stimuli: Chinese characters, half of which were consistently paired with pictures of animals or everyday objects in a learning phase. This phase was preceded and followed by a (pre- and postlearning) change-detection task to assess VWM performance. The results revealed that short-term retention was enhanced after learning, particularly for meaning-associated characters, although participants did not quite reach the accuracy level attained by native Chinese observers (young adults, N = 20). These results thus provide direct experimental evidence that participants' VWM of objects is boosted by them having acquired a long-term-memory association with meaning.
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PURPOSE: Pediatric meningioma differs not only in its rare incidence from the adult meningioma, but also in its clinical characteristics. Many treatment approaches of pediatric meningioma are based on the study results of adult meningioma studies. The aim of this study was to explore the clinical and epidemiological characteristics of pediatric meningioma. METHODS: Data on pediatric patients diagnosed between 1982 and 2021 with NF2-associated or sporadic meningioma and recruited in the trials/registries HIT-ENDO, KRANIOPHARYNGEOM 2000/2007 and KRANIOPHARYNGEOM Registry 2019 were retrospectively analyzed for clinical characteristics, etiology, histology, therapy, and outcome. RESULTS: One hundred fifteen study participants were diagnosed with sporadic or NF2-associated meningioma at a median age of 10.6 years. There was a 1:1 sex ratio, with 14% of study participants suffering from NF2. 46% of the meningiomas were located hemispherically, 17% at the optic nerve/ intraorbital and 10% ventricularly. Multiple meningiomas were detected in 69% of NF2 patients and in 9% of sporadic meningiomas. 50% of the meningiomas were WHO grade I, 37% WHO grade II and 6% WHO grade III. Progressions or recurrences occurred after a median interval of 1.9 years. Eight patients (7%) died, 3 of them due to disease. The event-free survival was higher for WHO grade I than for WHO grade II meningioma patients (p = 0.008). CONCLUSIONS: The major difference to the preceding literature could be found in the distribution of different WHO grades and their influence on event-free survival. Prospective studies are warranted to assess the impact of different therapeutic regimens. CLINICAL TRIAL REGISTRATION NUMBERS: NCT00258453; NCT01272622; NCT04158284.
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Neoplasias Meníngeas , Meningioma , Neurofibromatose 2 , Adulto , Humanos , Criança , Adolescente , Meningioma/epidemiologia , Meningioma/terapia , Neurofibromatose 2/complicações , Neurofibromatose 2/epidemiologia , Neurofibromatose 2/terapia , Neoplasias Meníngeas/epidemiologia , Neoplasias Meníngeas/terapia , Estudos Retrospectivos , Progressão da DoençaRESUMO
Pediatric craniopharyngioma is a rare tumor with excellent survival but significant long-term morbidities due to the loco-regional tumor growth or secondary to its treatment. Visual impairment, panhypopituitarism, hypothalamic damage, and behavioral changes are among the main challenges. This tumor should be managed under the care of a multidisciplinary team to determine the optimum treatment within the available resources. This is particularly important for low middle-income countries where resources are variable. This report provides risk-stratified management guidelines for children diagnosed with craniopharyngioma in a resource-limited setting.
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Craniofaringioma , Hipopituitarismo , Neoplasias Hipofisárias , Criança , Humanos , Craniofaringioma/terapia , Renda , Gestão de Riscos , Neoplasias Hipofisárias/terapiaRESUMO
Despite having relatively accurate timing, subjective time can be influenced by various contexts, such as stimulus spacing and sample frequency. Several electroencephalographic (EEG) components have been associated with timing, including the contingent negative variation (CNV), offset P2, and late positive component of timing (LPCt). However, the specific role of these components in the contextual modulation of perceived time remains unclear. In this study, we conducted two temporal bisection experiments to investigate this issue. Participants had to judge whether a test duration was close to a short or long standard. Unbeknownst to them, we manipulated the stimulus spacing (Experiment 1) and sample frequency (Experiment 2) to create short and long contexts while maintaining consistent test ranges and standards across different sessions. The results revealed that the bisection threshold shifted towards the ensemble mean, and both CNV and LPCt were sensitive to context modulation. In the short context, the CNV exhibited an increased climbing rate compared to the long context, whereas the LPCt displayed reduced amplitude and latency. These findings suggest that the CNV represents an expectancy wave preceding a temporal decision process, while the LPCt reflects the decision-making process itself, with both components influenced by the temporal context.
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Percepção do Tempo , Humanos , Percepção do Tempo/fisiologia , Eletroencefalografia , Variação Contingente Negativa/fisiologia , Fatores de TempoRESUMO
Salient-but-irrelevant stimuli (distractors) co-occurring with search targets can capture attention against the observer's will. Recently, evidence has accumulated that preparatory control can prevent this misguidance of spatial attention in predictable situations. However, the underlying mechanisms have remained elusive. Most pertinent theories assume that attention is guided by specific features. This widespread theoretical claim provides several strong predictions with regard to distractor handling that are disconfirmed here: Employing electrophysiological markers of covert attentional dynamics, in three experiments, we show that distractors standing out by a feature that is categorically different from the target consistently captures attention. However, equally salient distractors standing out in a different feature dimension are effectively down-weighted, even if unpredictably swapping their defining feature with the target. This shows that preparing for a distractor's feature is neither necessary nor sufficient for successful avoidance of attentional capture. Rather, capture is prevented by preparing for the distractor's feature dimension.
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Atenção , Atenção/fisiologia , Tempo de ReaçãoRESUMO
Observers can learn locations where salient distractors appear frequently to reduce potential interference-an effect attributed to better suppression of distractors at frequent locations. But how distractor suppression is implemented in the visual cortex and within the frontoparietal attention networks remains unclear. We used fMRI and a regional distractor-location learning paradigm with two types of distractors defined in either the same (orientation) or a different (color) dimension to the target to investigate this issue. fMRI results showed that BOLD signals in early visual cortex were significantly reduced for distractors (as well as targets) occurring at the frequent versus rare locations, mirroring behavioral patterns. This reduction was more robust with same-dimension distractors. Crucially, behavioral interference was correlated with distractor-evoked visual activity only for same- (but not different-) dimension distractors. Moreover, with different- (but not same-) dimension distractors, a color-processing area within the fusiform gyrus was activated more when a distractor was present in the rare region versus being absent and more with a distractor in the rare versus frequent locations. These results support statistical learning of frequent distractor locations involving regional suppression in early visual cortex and point to differential neural mechanisms of distractor handling with different- versus same-dimension distractors.
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Aprendizagem , Córtex Visual , Imageamento por Ressonância Magnética , Tempo de Reação , Lobo Temporal , Córtex Visual/diagnóstico por imagem , Percepção VisualRESUMO
Process interference or sharing of attentional resources between cognitive tasks and balance control during upright standing has been well documented. Attentional costs increase with greater balancing demands of a balance activity, for example in standing compared to sitting. The traditional approach for analyzing balance control using posturography with a force plate integrates across relative long trial periods of up to several minutes, which blends any balance adjustments and cognitive operations within this period. In the present study, we pursued an event-related approach to assess if single cognitive operations resolving response selection conflict in the Simon task interfere with concurrent balance control in quiet standing. In addition to traditional outcome measures (response latency, error proportions) in the cognitive Simon task, we investigated the effect of spatial congruency on measures of sway control. We expected that conflict resolution in incongruent trials would alter short-term progression of sway control. Our results demonstrated the expected congruency effect on performance in the cognitive Simon task and the mediolateral variability of balance control within 150 ms before the onset of the manual response was reduced to a greater degree in incongruent compared to congruent trials. In addition, mediolateral variability before and after the manual response was generally reduced compared to variability following target presentation, where no effect of congruency was observed. Assuming that response conflict in incongruent conditions requires suppression of the incorrect response tendencies, our results may imply that mechanisms of cognitive conflict resolution may also carry over to intermittent balance control mechanisms in a direction-specific manner.
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Cognição , Conflito Psicológico , Humanos , Tempo de Reação/fisiologia , Cognição/fisiologia , Fatores de Tempo , Atenção/fisiologiaRESUMO
BACKGROUND: Cranioparyngiomas are rare low-grade embryonic malformational tumors of the sellar/parasellar region. The prognosis after diagnosis during childood and adolescence is influenced by (neuro)endocrine long-term sequelae. A legal status of the degree of disability (GdB), according to the German Social Code Book V that is worthy of support provides financial means for psychosocial integration and participation of craniopharyngioma survivors. PATIENTS AND METHODS: HIT-Endo is a German registry study on craniopharyngioma patients aged≤18 years at diagnosis . In a sample of 108 patients, the degree of disability and the association with endocrine, ophthalmological, neuropsychological (QLQ-C30; MFI-20; FMH-scale) and psychosocial parameters was analyzed after a mean follow-up period of 16 years. RESULTS: 47 patients (43%) did not receive a GdB or received a GdB of 30-40, 43 patients (40%) a GdB of 50-90 and 18 patients (17%) the maximal GdB of 100. Higher GdB were associated with lower education, higher body mass index standard deviation and a higher degree of visual impairment and hypothalamic involvement of the craniopharyngioma. Patients with a GdB of 100 reported loss in physical and cognitive function, dyspnea, and pain (QLQ-C30), as well as fatigue (MFI-20), and limitations in social and occupational contexts. They further had a lower functional capacity (German daily life ability scale (FMH)) compared to those with a smaller GdB. CONCLUSION: The GdB is associated with psychosocial and physical impairments and reflects the long-term consequences of craniopharyngioma. A low functional capacity may indicate a high GdB in later life of craniopharyngioma survivors.
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Craniofaringioma , Neoplasias Hipofisárias , Adolescente , Humanos , Craniofaringioma/complicações , Craniofaringioma/psicologia , Seguimentos , Neoplasias Hipofisárias/diagnóstico , Neoplasias Hipofisárias/complicações , Prognóstico , Sobreviventes , Qualidade de VidaRESUMO
Using a combination of behavioral and EEG measures in a tactile odd-one-out search task with collocated visual items, we investigated the mechanisms underlying facilitation of search by repeated (vs. nonrepeated) spatial distractor-target configurations ("contextual cueing") when either the tactile (same-modality) or the visual array (different-modality) context was predictive of the location of the tactile singleton target. Importantly, in both conditions, the stimulation was multisensory, consisting of tactile plus visual items, although the target was singled out in the tactile modality and so the visual items were task-irrelevant. We found that when the predictive context was tactile, facilitation of search RTs by repeated configurations was accompanied by, and correlated with, enhanced lateralized ERP markers of pre-attentive (N1, N2) and, respectively focal-attentional processing (contralateral delay activity) not only over central ("somatosensory"), but also posterior ("visual") electrode sites, although the ERP effects were less marked over visual cortex. A similar pattern-of facilitated RTs and enhanced lateralized (N2 and contralateral delay activity) ERP components-was found when the predictive context was visual, although the ERP effects were less marked over somatosensory cortex. These findings indicate that both somatosensory and visual cortical regions contribute to the more efficient processing of the tactile target in repeated stimulus arrays, although their involvement is differentially weighted depending on the sensory modality that contains the predictive information.
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Percepção do Tato , Tato , Atenção/fisiologia , Sinais (Psicologia) , Humanos , Córtex Somatossensorial/fisiologia , Tato/fisiologia , Percepção do Tato/fisiologiaRESUMO
Cognitive complaints of attention/concentration problems are highly frequent in older adults with subjective cognitive decline (SCD). Functional connectivity in the cingulo-opercular network (CON-FC) supports cognitive control, tonic alertness, and visual processing speed. Thus, those complaints in SCD may reflect a decrease in CON-FC. Frontal white-matter tracts such as the forceps minor exhibit age- and SCD-related alterations and, therefore, might influence the CON-FC decrease in SCD. Here, we aimed to determine whether SCD predicts an impairment in CON-FC and whether neurite density in the forceps minor modulates that effect. To do so, we integrated cross-sectional and longitudinal analyses of multimodal data in a latent growth curve modeling approach. Sixty-nine healthy older adults (13 males; 68.33 ± 7.95 years old) underwent resting-state functional and diffusion-weighted magnetic resonance imaging, and the degree of SCD was assessed at baseline with the memory functioning questionnaire (greater score indicating more SCD). Forty-nine of the participants were further enrolled in two follow-ups, each about 18 months apart. Baseline SCD did not predict CON-FC after three years or its rate of change (p-values > 0.092). Notably, however, the forceps minor neurite density did modulate the relation between SCD and CON-FC (intercept; b = 0.21, 95% confidence interval, CI, [0.03, 0.39], p = 0.021), so that SCD predicted a greater CON-FC decrease in older adults with relatively lower neurite density in the forceps minor. The neurite density of the forceps minor, in turn, negatively correlated with age. These results suggest that CON-FC alterations in SCD are dependent upon the forceps minor neurite density. Accordingly, these results imply modifiable age-related factors that could help delay or mitigate both age and SCD-related effects on brain connectivity.
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Disfunção Cognitiva , Neuritos , Masculino , Humanos , Idoso , Pessoa de Meia-Idade , Estudos Transversais , Encéfalo , Disfunção Cognitiva/diagnóstico por imagem , Instrumentos Cirúrgicos , Imageamento por Ressonância Magnética/métodosRESUMO
In visual search tasks, repeating features or the position of the target results in faster response times. Such inter-trial 'priming' effects occur not just for repetitions from the immediately preceding trial but also from trials further back. A paradigm known to produce particularly long-lasting inter-trial effects-of the target-defining feature, target position, and response (feature)-is the 'priming of pop-out' (PoP) paradigm, which typically uses sparse search displays and random swapping across trials of target- and distractor-defining features. However, the mechanisms underlying these inter-trial effects are still not well understood. To address this, we applied a modeling framework combining an evidence accumulation (EA) model with different computational updating rules of the model parameters (i.e., the drift rate and starting point of EA) for different aspects of stimulus history, to data from a (previously published) PoP study that had revealed significant inter-trial effects from several trials back for repetitions of the target color, the target position, and (response-critical) target feature. By performing a systematic model comparison, we aimed to determine which EA model parameter and which updating rule for that parameter best accounts for each inter-trial effect and the associated n-back temporal profile. We found that, in general, our modeling framework could accurately predict the n-back temporal profiles. Further, target color- and position-based inter-trial effects were best understood as arising from redistribution of a limited-capacity weight resource which determines the EA rate. In contrast, response-based inter-trial effects were best explained by a bias of the starting point towards the response associated with a previous target; this bias appeared largely tied to the position of the target. These findings elucidate how our cognitive system continually tracks, and updates an internal predictive model of, a number of separable stimulus and response parameters in order to optimize task performance.
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Simulação por Computador , Humanos , Tempo de Reação/fisiologia , Reprodutibilidade dos Testes , Análise e Desempenho de TarefasRESUMO
BACKGROUND AND PURPOSE: Fatigue and low sleep quality in multiple sclerosis (MS) are closely related symptoms. Here, the associations between the brain's functional connectivity (FC) and fatigue and low sleep quality were investigated to determine the degree of neural distinctiveness of these symptoms. METHOD: A hundred and four patients with relapsing-remitting MS (age 38.9 ± 10.2 years, 66 females) completed the Modified Fatigue Impact Scale and the Pittsburgh Sleep Quality Index and underwent resting-state functional magnetic resonance imaging. FC was analyzed using independent-component analysis in sensorimotor, default-mode, fronto-parietal and basal-ganglia networks. Multiple linear regression models allowed us to test the association between FC and fatigue and sleep quality whilst controlling for one another as well as for demographic, disease-related and imaging variables. RESULTS: Higher fatigue correlated with lower sleep quality (r = 0.54, p < 0.0001). Higher fatigue was associated with lower FC of the precentral gyrus in the sensorimotor network, the precuneus in the posterior default-mode network and the superior frontal gyrus in the left fronto-parietal network, independently of sleep quality. Lower sleep quality was associated with lower FC of the left intraparietal sulcus in the left fronto-parietal network, independently of fatigue. Specific associations were found between fatigue and the sensorimotor network's global FC and between low sleep quality and the left fronto-parietal network's global FC. CONCLUSION: Despite the high correlation between fatigue and low sleep quality in the clinical picture, our findings clearly indicate that, on the neural level, fatigue and low sleep quality in MS are associated with decreased FC in distinct functional brain networks.
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Esclerose Múltipla , Adulto , Encéfalo/patologia , Mapeamento Encefálico/métodos , Fadiga/complicações , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/patologia , Qualidade do SonoRESUMO
Visual information processing requires an efficient visual attention system. The neural theory of visual attention (TVA) proposes that visual processing speed depends on the coordinated activity between frontoparietal and occipital brain areas. Previous research has shown that the coordinated activity between (i.e., functional connectivity and "inter-FC") cingulo-opercular (COn) and right-frontoparietal (RFPn) networks is linked to visual processing speed. However, how inter-FC of COn and RFPn with visual networks links to visual processing speed has not been directly addressed yet. Forty-eight healthy adult participants (27 females) underwent resting-state (rs-)fMRI and performed a whole-report psychophysical task. To obtain inter-FC, we analyzed the entire frequency range available in our rs-fMRI data (i.e., 0.01-0.4 Hz) to avoid discarding neural information. Following previous approaches, we analyzed the data across frequency bins (Hz): Slow-5 (0.01-0.027), Slow-4 (0.027-0.073), Slow-3 (0.073-0.198), and Slow-2 (0.198-0.4). We used the mathematical TVA framework to estimate an individual, latent-level visual processing speed parameter. We found that visual processing speed was negatively associated with inter-FC between RFPn and visual networks in Slow-5 and Slow-2, with no corresponding significant association for inter-FC between COn and visual networks. These results provide the first empirical evidence that links inter-FC between RFPn and visual networks with the visual processing speed parameter. These findings suggest that direct connectivity between occipital and right frontoparietal, but not frontoinsular, regions support visual processing speed.
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Mapeamento Encefálico , Percepção Visual , Adulto , Encéfalo , Cognição , Feminino , Humanos , Imageamento por Ressonância Magnética , Vias Neurais/diagnóstico por imagemRESUMO
Illusory figures demonstrate the visual system's ability to integrate disparate parts into coherent wholes. We probed this object integration process by either presenting an integrated diamond shape or a comparable ungrouped configuration that did not render a complete object. Two tasks were used that either required localization of a target dot (relative to the presented configuration) or discrimination of the dot's luminance. The results showed that only when the configuration was task relevant (in the localization task), performance benefited from the presentation of an integrated object. Concurrent functional magnetic resonance imaging was performed and analyzed using dynamic causal modeling to investigate the (causal) relationship between regions that are associated with illusory figure completion. We found object-specific feedback connections between the lateral occipital cortex (LOC) and early visual cortex (V1/V2). These modulatory connections persisted across task demands and hemispheres. Our results thus provide direct evidence that interactions between mid-level and early visual processing regions engage in illusory figure perception. These data suggest that LOC first integrates inputs from multiple neurons in lower-level cortices, generating a global shape representation while more fine-graded object details are then determined via feedback to early visual areas, independently of the current task demands.
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Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Lobo Occipital/diagnóstico por imagem , Lobo Occipital/fisiologia , Percepção Visual/fisiologia , Adulto , Retroalimentação , Humanos , Ilusões/fisiologia , Modelos Teóricos , Córtex Visual/diagnóstico por imagem , Córtex Visual/fisiologiaRESUMO
In contrast to adults, meningiomas are uncommon tumors in childhood and adolescence. Whether adult and pediatric meningiomas differ on a molecular level is unclear. Here we report detailed genomic analyses of 37 pediatric meningiomas by sequencing and DNA methylation profiling. Histologically, the series was dominated by meningioma subtypes with aggressive behavior, with 70% of patients suffering from WHO grade II or III meningiomas. The most frequent cytogenetic aberrations were loss of chromosomes 22 (23/37 [62%]), 1 (9/37 [24%]), 18 (7/37 [19%]), and 14 (5/37 [14%]). Tumors with NF2 alterations exhibited overall increased chromosomal instability. Unsupervised clustering of DNA methylation profiles revealed separation into three groups: designated group 1 composed of clear cell and papillary meningiomas, whereas group 2A comprised predominantly atypical meningiomas and group 2B enriched for rare high-grade subtypes (rhabdoid, chordoid). Meningiomas from NF2 patients clustered exclusively within groups 1 and 2A. When compared with a dataset of 105 adult meningiomas, the pediatric meningiomas largely grouped separately. Targeted panel DNA sequencing of 34 tumors revealed frequent NF2 alterations, while other typical alterations found in adult non-NF2 tumors were absent. These data demonstrate that pediatric meningiomas are characterized by molecular features distinct from adult tumors.