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1.
Behav Brain Sci ; 46: e258, 2023 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-37779271

RESUMO

The Chinese writing system is unique in its implementation of graphemic, phonological, morphological, and semantic features. We add nuances to its portrait in the target article and highlight research on radically different timelines of phonological and semantic activation during reading of Chinese and alphabetic script, paving the way for the identification of universal and culture-specific cognitive processing.


Assuntos
Cognição , Leitura , Humanos , Linguística , Semântica , Idioma
2.
Behav Res Methods ; 55(5): 2467-2484, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36002625

RESUMO

The a priori calculation of statistical power has become common practice in behavioral and social sciences to calculate the necessary sample size for detecting an expected effect size with a certain probability (i.e., power). In multi-factorial repeated measures ANOVA, these calculations can sometimes be cumbersome, especially for higher-order interactions. For designs that only involve factors with two levels each, the paired t test can be used for power calculations, but some pitfalls need to be avoided. In this tutorial, we provide practical advice on how to express main and interaction effects in repeated measures ANOVA as single difference variables. In particular, we demonstrate how to calculate the effect size Cohen's d of this difference variable either based on means, variances, and covariances of conditions or by transforming [Formula: see text] or [Formula: see text] from the ANOVA framework into d. With the effect size correctly specified, we then show how to use the t test for sample size considerations by means of an empirical example. The relevant R code is provided in an online repository for all example calculations covered in this article.


Assuntos
Projetos de Pesquisa , Humanos , Tamanho da Amostra , Probabilidade , Análise de Variância
3.
Behav Res Methods ; 54(4): 1989-2000, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-34816386

RESUMO

This report introduces the Beijing Sentence Corpus (BSC). This is a Chinese sentence corpus of eye-tracking data with relatively clear word boundaries. In addition, we report predictability norms for each word in the corpus. Eye movement corpora are available in alphabetic scripts such as English, German, and French. However, there is no publicly available corpus for Chinese. Thus, to study predictive processes during reading in Chinese, it is necessary to establish such a corpus. Also, given the clear word boundaries in the sentences, BSC is especially useful to provide evidence relevant to the theoretical debate of saccade target selection in Chinese. With the large-scale predictability norms, we conducted new analyses based on 60 BSC readers, testing the influences of launch word and target word properties while controlling for visual and oculomotor constraints, as well as sentence and subject-level individual differences. We discuss implications for guidance of eye movements in Chinese reading.


Assuntos
Movimentos Oculares , Leitura , Pequim , Humanos , Idioma , Movimentos Sacádicos
4.
Bull Math Biol ; 83(1): 1, 2020 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-33289877

RESUMO

Newly emerging pandemics like COVID-19 call for predictive models to implement precisely tuned responses to limit their deep impact on society. Standard epidemic models provide a theoretically well-founded dynamical description of disease incidence. For COVID-19 with infectiousness peaking before and at symptom onset, the SEIR model explains the hidden build-up of exposed individuals which creates challenges for containment strategies. However, spatial heterogeneity raises questions about the adequacy of modeling epidemic outbreaks on the level of a whole country. Here, we show that by applying sequential data assimilation to the stochastic SEIR epidemic model, we can capture the dynamic behavior of outbreaks on a regional level. Regional modeling, with relatively low numbers of infected and demographic noise, accounts for both spatial heterogeneity and stochasticity. Based on adapted models, short-term predictions can be achieved. Thus, with the help of these sequential data assimilation methods, more realistic epidemic models are within reach.


Assuntos
COVID-19/epidemiologia , Pandemias , SARS-CoV-2 , Infecções Assintomáticas/epidemiologia , Número Básico de Reprodução/estatística & dados numéricos , COVID-19/transmissão , Simulação por Computador , Interpretação Estatística de Dados , Alemanha/epidemiologia , Humanos , Funções Verossimilhança , Conceitos Matemáticos , Modelos Biológicos , Modelos Estatísticos , Pandemias/estatística & dados numéricos , Processos Estocásticos , Fatores de Tempo
5.
Gerontology ; 65(4): 332-339, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30336478

RESUMO

BACKGROUND: Dynamic balance keeps the vertical projection of the center of mass within the base of support while walking. Dynamic balance tests are used to predict the risks of falls and eventual falls. The psychometric properties of most dynamic balance tests are unsatisfactory and do not comprise an actual loss of balance while walking. OBJECTIVES: Using beam walking distance as a measure of dynamic balance, the BEAM consortium will determine the psychometric properties, lifespan and patient reference values, the relationship with selected "dynamic balance tests," and the accuracy of beam walking distance to predict falls. METHODS: This cross-sectional observational study will examine healthy adults in 7 decades (n = 432) at 4 centers. Center 5 will examine patients (n = 100) diagnosed with Parkinson's disease, multiple sclerosis, stroke, and balance disorders. In test 1, all participants will be measured for demographics, medical history, muscle strength, gait, static balance, dynamic balance using beam walking under single (beam walking only) and dual task conditions (beam walking while concurrently performing an arithmetic task), and several cognitive functions. Patients and healthy participants age 50 years or older will be additionally measured for fear of falling, history of falls, miniBESTest, functional reach on a force platform, timed up and go, and reactive balance. All participants age 50 years or older will be recalled to report fear of falling and fall history 6 and 12 months after test 1. In test 2, seven to ten days after test 1, healthy young adults and age 50 years or older (n = 40) will be retested for reliability of beam walking performance. CONCLUSION: We expect to find that beam walking performance vis-à-vis the traditionally used balance outcomes predicts more accurately fall risks and falls. CLINICAL TRIAL REGISTRATION NUMBER: NCT03532984.


Assuntos
Acidentes por Quedas/estatística & dados numéricos , Esclerose Múltipla/fisiopatologia , Doença de Parkinson/fisiopatologia , Equilíbrio Postural/fisiologia , Transtornos de Sensação/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Caminhada , Adulto , Idoso , Estudos de Casos e Controles , Estudos Transversais , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Adulto Jovem
6.
Behav Res Methods ; 51(3): 1161-1178, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-29907908

RESUMO

This article introduces a new corpus of eye movements in silent reading-the Russian Sentence Corpus (RSC). Russian uses the Cyrillic script, which has not yet been investigated in cross-linguistic eye movement research. As in every language studied so far, we confirmed the expected effects of low-level parameters, such as word length, frequency, and predictability, on the eye movements of skilled Russian readers. These findings allow us to add Slavic languages using Cyrillic script (exemplified by Russian) to the growing number of languages with different orthographies, ranging from the Roman-based European languages to logographic Asian ones, whose basic eye movement benchmarks conform to the universal comparative science of reading (Share, 2008). We additionally report basic descriptive corpus statistics and three exploratory investigations of the effects of Russian morphology on the basic eye movement measures, which illustrate the kinds of questions that researchers can answer using the RSC. The annotated corpus is freely available from its project page at the Open Science Framework: https://osf.io/x5q2r/ .


Assuntos
Movimentos Oculares , Leitura , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Atenção , Benchmarking , Olho Artificial , Feminino , Humanos , Linguística , Masculino , Pessoa de Meia-Idade , Federação Russa , Adulto Jovem
7.
Mem Cognit ; 46(5): 729-740, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29435825

RESUMO

During sentence reading, low spatial frequency information afforded by spaces between words is the primary factor for eye guidance in spaced writing systems, whereas saccade generation for unspaced writing systems is less clear and under debate. In the present study, we investigated whether word-boundary information, provided by alternating colors (consistent or inconsistent with word-boundary information) influences saccade-target selection in Chinese. In Experiment 1, as compared to a baseline (i.e., uniform color) condition, word segmentation with alternating color shifted fixation location towards the center of words. In contrast, incorrect word segmentation shifted fixation location towards the beginning of words. In Experiment 2, we used a gaze-contingent paradigm to restrict the color manipulation only to the upcoming parafoveal words and replicated the results, including fixation location effects, as observed in Experiment 1. These results indicate that Chinese readers are capable of making use of parafoveal word-boundary knowledge for saccade generation, even if such information is unfamiliar to them. The present study provides novel support for the hypothesis that word segmentation is involved in the decision about where to fixate next during Chinese reading.


Assuntos
Percepção de Cores/fisiologia , Movimentos Oculares/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Psicolinguística , Leitura , Adulto , China , Humanos , Adulto Jovem
8.
Behav Res Methods ; 50(5): 1882-1894, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-28917056

RESUMO

The analysis of large experimental datasets frequently reveals significant interactions that are difficult to interpret within the theoretical framework guiding the research. Some of these interactions actually arise from the presence of unspecified nonlinear main effects and statistically dependent covariates in the statistical model. Importantly, such nonlinear main effects may be compatible (or, at least, not incompatible) with the current theoretical framework. In the present literature, this issue has only been studied in terms of correlated (linearly dependent) covariates. Here we generalize to nonlinear main effects (i.e., main effects of arbitrary shape) and dependent covariates. We propose a novel nonparametric method to test for ambiguous interactions where present parametric methods fail. We illustrate the method with a set of simulations and with reanalyses (a) of effects of parental education on their children's educational expectations and (b) of effects of word properties on fixation locations during reading of natural sentences, specifically of effects of length and morphological complexity of the word to be fixated next. The resolution of such ambiguities facilitates theoretical progress.


Assuntos
Análise de Variância , Psicologia Educacional/estatística & dados numéricos , Leitura , Pesquisa Comportamental/métodos , Pesquisa Comportamental/estatística & dados numéricos , Análise Fatorial , Humanos , Análise de Regressão
9.
J Neurosci ; 36(4): 1237-41, 2016 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-26818511

RESUMO

During visual fixation, the eye generates microsaccades and slower components of fixational eye movements that are part of the visual processing strategy in humans. Here, we show that ongoing heartbeat is coupled to temporal rate variations in the generation of microsaccades. Using coregistration of eye recording and ECG in humans, we tested the hypothesis that microsaccade onsets are coupled to the relative phase of the R-R intervals in heartbeats. We observed significantly more microsaccades during the early phase after the R peak in the ECG. This form of coupling between heartbeat and eye movements was substantiated by the additional finding of a coupling between heart phase and motion activity in slow fixational eye movements; i.e., retinal image slip caused by physiological drift. Our findings therefore demonstrate a coupling of the oculomotor system and ongoing heartbeat, which provides further evidence for bodily influences on visuomotor functioning. SIGNIFICANCE STATEMENT: In the present study, we show that microsaccades are coupled to heartbeat. Moreover, we revealed a strong modulation of slow eye movements around the R peak in the ECG. These results suggest that heartbeat as a basic physiological signal is related to statistical modulations of fixational eye movements, in particular, the generation of microsaccades. Therefore, our findings add a new perspective on the principles underlying the generation of fixational eye movements. Importantly, our study highlights the need to record eye movements when studying the influence of heartbeat in neuroscience to avoid misinterpretation of eye-movement-related artifacts as heart-evoked modulations of neural processing.


Assuntos
Frequência Cardíaca/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Eletrocardiografia , Feminino , Fixação Ocular , Humanos , Masculino , Estimulação Luminosa , Adulto Jovem
10.
Mem Cognit ; 45(3): 480-492, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27787683

RESUMO

Masson and Kliegl (Journal of Experimental Psychology: Learning, Memory, and Cognition, 39, 898-914, 2013) reported evidence that the nature of the target stimulus on the previous trial of a lexical decision task modulates the effects of independent variables on the current trial, including additive versus interactive effects of word frequency and stimulus quality. In contrast, recent reanalyses of previously published data from experiments that, unlike the Masson and Kliegl experiments, did not include semantic priming as a factor, found no evidence for modulation of additive effects of frequency and stimulus quality by trial history (Balota, Aschenbrenner, & Yap, Journal of Experimental Psychology: Learning, Memory, and Cognition, 39, 1563-1571, 2013; O'Malley & Besner, Journal of Experimental Psychology: Learning, Memory, and Cognition, 34, 1400-1411, 2013). We report two experiments that included semantic priming as a factor and that attempted to replicate the modulatory effects found by Masson and Kliegl. In neither experiment was additivity of frequency and stimulus quality modulated by trial history, converging with the findings reported by Balota et al. and O'Malley and Besner. Other modulatory influences of trial history, however, were replicated in the new experiments and reflect potential trial-by-trial alterations in decision processes.


Assuntos
Psicolinguística , Priming de Repetição/fisiologia , Semântica , Adulto , Humanos , Adulto Jovem
11.
Behav Res Methods ; 47(4): 1085-1094, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25319039

RESUMO

This article introduces childLex, an online database of German read by children. childLex is based on a corpus of children's books and comprises 10 million words that were syntactically annotated and lemmatized. childLex reports linguistic norms for lexical, superlexical, and sublexical variables in three different age groups: 6-8 (grades 1-2), 9-10 (grades 3-4), and 11-12 years (grades 5-6). Here, we describe how childLex was collected and analyzed. In addition, we provide information about the distributions of word frequency, word length, and orthographic neighborhood size, as well as their intercorrelations. Finally, we explain how childLex can be accessed using a Web interface.


Assuntos
Linguagem Infantil , Bases de Dados Factuais , Idioma , Leitura , Criança , Feminino , Humanos , Linguística , Masculino
12.
Neuroimage ; 94: 193-202, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24642288

RESUMO

Humans typically read at incredibly fast rates, because they predict likely occurring words from a given context. Here, we used functional near-infrared spectroscopy (fNIRS) to track the ultra-rapid hemodynamic responses of words presented every 280 ms in a naturally paced sentence context. We found a lower occipital deoxygenation to unpredictable than to predictable words. The greater hemodynamic responses to unexpected words suggest that the visual features of expected words have been pre-activated previous to stimulus presentation. Second, we tested opposing theoretical proposals about the role of the medial orbitofrontal cortex (OFC): Either OFC may respond to the breach of expectation; or OFC is activated when the present stimulus matches the prediction. A significant interaction between word frequency and predictability indicated OFC responses to breaches of expectation for low- but not for high-frequency words: OFC is sensitive to both, bottom-up processing as mediated by word frequency, as well as top-down predictions. Particularly, when a rare word is unpredictable, OFC becomes active. Finally, we discuss how a high temporal resolution can help future studies to disentangle the hemodynamic responses of single trials in such an ultra-rapid event succession as naturally paced reading.


Assuntos
Mapeamento Encefálico/métodos , Circulação Cerebrovascular/fisiologia , Lobo Occipital/fisiologia , Consumo de Oxigênio/fisiologia , Córtex Pré-Frontal/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Percepção Visual/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Compreensão/fisiologia , Feminino , Humanos , Masculino , Oximetria/métodos , Leitura , Análise e Desempenho de Tarefas
13.
Memory ; 22(4): 374-89, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-23663040

RESUMO

The effect of repeating features in a short-term memory task was tested in three experiments. Experiments 1 and 2 used a recognition paradigm. Participants encoded four serially presented objects and then decided whether a probe matched one of them with regard to all three features. In the control condition no feature was repeated; in the experimental condition features were repeated in two memory objects. Experiment 3 used a cued recall paradigm with the same list design. After list presentation one feature was used as a cue uniquely indicating one of the memory objects. Participants recalled the remaining two features of the probed object. Feature overwriting as one component of the interference model of Oberauer and Kliegl (2006) predicts worse performance in the experimental compared to the control condition. Results of all three experiments did not support this hypothesis. Recognition performances in Experiments 1 and 2 were not impaired by repeating features. Recall performance in Experiment 3 was better for repeated features, contrary to the predictions of feature overwriting. Predictions from feature overwriting for the shape of serial position curves were also not confirmed.


Assuntos
Memória de Curto Prazo , Percepção Visual , Adolescente , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino , Rememoração Mental , Reconhecimento Psicológico , Adulto Jovem
14.
Sci Rep ; 14(1): 11500, 2024 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-38769417

RESUMO

The dissociation of effects of age, time of assessment and cohort is a well-known challenge in developmental science. We examined effects of time of assessment in the school year on children's physical fitness using data from 75,362 German third-graders from seven cohorts. Children were tested once either in the first or second school term of third grade. Tests examined cardiorespiratory endurance (6-min run), coordination (star-run), speed (20-m sprint), lower (standing long jump) and upper (ball-push test) limbs muscle power, and flexibility (stand-and-reach test). We estimated the effect of time of assessment using a regression discontinuity design specified in a linear mixed model with random factors child and school and adjusted for age, sex, and cohort effects. Coordination, speed, and upper limbs muscle power were better in second compared to first school term, with boys exhibiting a larger increase of upper limbs muscle power than girls. There was no evidence for changes in cardiorespiratory endurance, lower limbs muscle power, and flexibility between assessments. Previously reported age and sex effects as well as secular fitness trends were replicated. There is thus evidence for improvement of some physical fitness components beyond age and cohort effects that presumably reflects the benefit of physical activity in physical education and other settings. Effects of assessment time should be taken into consideration in performance-based grading or norm-based selection of children.


Assuntos
Aptidão Física , Instituições Acadêmicas , Humanos , Masculino , Feminino , Criança , Aptidão Física/fisiologia , Aptidão Cardiorrespiratória/fisiologia , Exercício Físico/fisiologia , Alemanha , Força Muscular/fisiologia , Fatores de Tempo , Resistência Física/fisiologia
15.
Artigo em Inglês | MEDLINE | ID: mdl-38573721

RESUMO

Perceptual span in reading, the spatial extent for effective information extraction during a single fixation, provides a critical foundation to all studies for sentence reading. However, it is not understood fully how the perceptual span is influenced by direction-specific reading experience. Traditional Chinese sentences can be written horizontally from left to right or vertically downward, offering the best opportunity to explore readers' perceptual span in different text directions, free of possible confounding with language proficiency and cross-participant differences. Using a within-item and within-subject design, eye movements of traditional Chinese readers were recorded during their reading of horizontally and vertically presented sentences. Additionally, regardless of text direction, a gaze-contingent moving-window technique was adopted to restrict visible texts within a virtual window that moved in synchrony with the reader's eye gaze, while characters outside the window were masked. Among several critical results, most importantly, asymptotic reading performance was observed in a smaller window condition for vertical reading than for horizontal reading, suggesting an overall smaller perceptual span in the former case. In addition, the size of the vertical perceptual span increased as a function of the readers' familiarity with vertical text. We conclude that factors beyond orthographic complexity and readers' language proficiency can influence the way in which humans read. Readers' direction-specific perceptual experiences can influence their perceptual span. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

16.
Sci Rep ; 14(1): 11817, 2024 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-38783047

RESUMO

We assessed lifespan development of multitasking in a sample of 187 individuals aged 8-82 years. Participants performed a visuo-spatial working memory (VSWM) task together with either postural control or reaction time (RT) tasks. Using criterion-referenced testing we individually adjusted difficulty levels for the VSWM task to control for single-task differences. Age-differences in single-task performances followed U-shaped patterns with young adults outperforming children and older adults. Multitasking manipulations yielded robust performance decrements in VSWM, postural control and RT tasks. Presumably due to our adjustment of VSWM challenges, costs in this task were small and similar across age groups suggesting that age-differential costs found in earlier studies largely reflected differences already present during single-task performance. Age-differences in multitasking costs for concurrent tasks depended on specific combinations. For VSWM and RT task combinations increases in RT were the smallest for children but pronounced in adults highlighting the role of cognitive control processes. Stabilogram diffusion analysis of postural control demonstrated that long-term control mechanisms were affected by concurrent VSWM demands. This interference was pronounced in older adults supporting concepts of compensation or increased cognitive involvement in sensorimotor processes at older age. Our study demonstrates how a lifespan approach can delineate the explanatory scope of models of human multitasking.


Assuntos
Memória de Curto Prazo , Tempo de Reação , Humanos , Idoso , Adulto , Adolescente , Criança , Feminino , Masculino , Idoso de 80 Anos ou mais , Tempo de Reação/fisiologia , Pessoa de Meia-Idade , Adulto Jovem , Memória de Curto Prazo/fisiologia , Equilíbrio Postural/fisiologia , Desempenho Psicomotor/fisiologia , Comportamento Multitarefa/fisiologia , Análise e Desempenho de Tarefas , Envelhecimento/fisiologia , Longevidade/fisiologia , Cognição/fisiologia
17.
Dev Sci ; 16(6): 967-79, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24118721

RESUMO

We measured Chinese dyslexic and control children's eye movements during rapid automatized naming (RAN) with alphanumeric (digits) and symbolic (dice surfaces) stimuli. Both types of stimuli required identical oral responses, controlling for effects associated with speech production. Results showed that naming dice was much slower than naming digits for both groups, but group differences in eye-movement measures and in the eye-voice span (i.e. the distance between the currently fixated item and the voiced item) were generally larger in digit-RAN than in dice-RAN. In addition, dyslexics were less efficient in parafoveal processing in these RAN tasks. Since the two RAN tasks required the same phonological output and on the assumption that naming dice is less practiced than naming digits in general, the results suggest that the translation of alphanumeric visual symbols into phonological codes is less efficient in dyslexic children. The dissociation of the print-to-sound conversion and phonological representation suggests that the degree of automaticity in translation from visual symbols to phonological codes in addition to phonological processing per se is also critical to understanding dyslexia.


Assuntos
Dislexia , Movimentos Oculares/fisiologia , Fonética , Leitura , Criança , China , Feminino , Humanos , Idioma , Desenvolvimento da Linguagem , Masculino , Tempo de Reação , Fala
18.
J Exp Child Psychol ; 115(3): 579-89, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23499320

RESUMO

Dyslexic children are known to be slower than normal readers in rapid automatized naming (RAN). This suggests that dyslexics encounter local processing difficulties, which presumably induce a narrower perceptual span. Consequently, dyslexics should suffer less than normal readers from removing parafoveal preview. Here we used a gaze-contingent moving window paradigm in a RAN task to experimentally test this prediction. Results indicate that dyslexics extract less parafoveal information than control children. We propose that more attentional resources are recruited to the foveal processing because of dyslexics' less automatized translation of visual symbols into phonological output, thereby causing a reduction of the perceptual span. This in turn leads to less efficient preactivation of parafoveal information and, hence, more difficulty in processing the next foveal item.


Assuntos
Dislexia/fisiopatologia , Movimentos Oculares , Estudos de Casos e Controles , Criança , China , Dislexia/psicologia , Movimentos Oculares/fisiologia , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Tempo de Reação/fisiologia , Leitura , Percepção Visual
19.
J Vis ; 13(5)2013 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-23584632

RESUMO

Primary saccades are often followed by small secondary saccades, which are generally thought to reduce the distance between the saccade endpoint and target location. Accumulated evidence demonstrates that secondary saccades are subject to various influences, among which retinal feedback during postsaccadic fixation constitutes only one important signal. Recently, we reported that target eccentricity and an orientation bias influence the generation of secondary saccades. In the present study, we examine secondary saccades in the absence of postsaccadic visual feedback. Although extraretinal signals (e.g., efference copy) have received widespread attention in eye-movement studies, it is still unclear whether an extraretinal error signal contributes to the programming of secondary saccades. We have observed that secondary saccade latency and amplitude depend on primary saccade error despite the absence of postsaccadic visual feedback. Strong evidence for an extraretinal error signal influencing secondary saccade programming is given by the observation that secondary saccades are more likely to be oriented in a direction opposite to the primary saccade as primary saccade error shifts from target undershoot to overshoot. We further show how the functional relationship between primary saccade landing position and secondary saccade characteristics varies as a function of target eccentricity. We propose that initial target eccentricity and an extraretinal error signal codetermine the postsaccadic activity distribution in the saccadic motor map when no visual feedback is available.


Assuntos
Retroalimentação Sensorial/fisiologia , Movimentos Sacádicos/fisiologia , Adulto , Análise de Variância , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos , Tempo de Reação , Adulto Jovem
20.
Sci Rep ; 13(1): 541, 2023 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-36631521

RESUMO

Lifespan development of postural control shows as an inverted U-shaped function with optimal performance in young adults and similar levels of underperformance in children and older adults. However, similarities in children and older adults might conceal differences in underlying control processes. We mapped out age-related differences in postural control using center-of-pressure trajectories of 299 participants ranging from 7 to 81 years old in three tasks: stable stance, compromised vision, and narrowed base of support. Summary statistics (path length, ellipse area) replicated the well-known U-shape function also showing that compromising vision and narrowing the base of support affected older adults more than children. Stabilogram diffusion analysis (SDA) allows to assess postural control performance in terms of diffusion at short (< 1 s) and longer timescales. SDA parameters showed the strongest short-term drift in older adults, especially under compromised vision or narrowed base of support conditions. However, older adults accommodated their poor short-term control by corrective adjustments as reflected in long-term diffusion under eyes closed conditions and initiating anti-persistent behavior earlier compared with children and young adults in tandem stance. We argue that these results highlight the adaptability of the postural control system and warrant a reinterpretation of previous postural control frameworks.


Assuntos
Longevidade , Postura , Adulto Jovem , Criança , Humanos , Idoso , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Equilíbrio Postural , Olho
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