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Purpose: To use finite element (FE) analysis to assess what morphologic and biomechanical factors of the iris and anterior chamber are more likely to influence angle narrowing during pupil dilation. Methods: The study consisted of 1344 FE models comprising the cornea, sclera, lens, and iris to simulate pupil dilation. For each model, we varied the following parameters: anterior chamber depth (ACD = 2-4 mm) and anterior chamber width (ACW = 10-12 mm), iris convexity (IC = 0-0.3 mm), iris thickness (IT = 0.3-0.5 mm), stiffness (E = 4-24 kPa), and Poisson's ratio (v = 0-0.3). We evaluated the change in (â³â ) and the final dilated angles (â f) from baseline to dilation for each parameter. Results: The final dilated angles decreased with a smaller ACD (â f = 53.4° ± 12.3° to 21.3° ± 14.9°), smaller ACW (â f = 48.2° ± 13.5° to 26.2° ± 18.2°), larger IT (â f = 52.6° ± 12.3° to 24.4° ± 15.1°), larger IC (â f = 45.0° ± 19.2° to 33.9° ± 16.5°), larger E (â f = 40.3° ± 17.3° to 37.4° ± 19.2°), and larger v (â f = 42.7° ± 17.7° to 34.2° ± 18.1°). The change in angles increased with larger ACD (â³â = 9.37° ± 11.1° to 15.4° ± 9.3°), smaller ACW (â³â = 7.4° ± 6.8° to 16.4° ± 11.5°), larger IT (â³â = 5.3° ± 7.1° to 19.3° ± 10.2°), smaller IC (â³â = 5.4° ± 8.2° to 19.5° ± 10.2°), larger E (â³â = 10.9° ± 12.2° to 13.1° ± 8.8°), and larger v (â³â = 8.1° ± 9.4° to 16.6° ± 10.4°). Conclusions: The morphology of the iris (IT and IC) and its innate biomechanical behavior (E and v) were crucial in influencing the way the iris deformed during dilation, and angle closure was further exacerbated by decreased anterior chamber biometry (ACD and ACW).
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Análisis de Elementos Finitos , Iris , Pupila , Humanos , Iris/anatomía & histología , Pupila/fisiología , Fenómenos Biomecánicos , Glaucoma de Ángulo Cerrado/fisiopatología , Presión Intraocular/fisiología , Cámara Anterior/diagnóstico por imagen , Cámara Anterior/anatomía & histología , Córnea/fisiología , Córnea/anatomía & histología , EscleróticaRESUMEN
We investigated the relations between self-reported math anxiety, task difficulty, and pupil dilation in adults and very young children during math tasks of varying difficulty levels. While task difficulty significantly influenced pupillary responses in both groups, the association between self-reported math anxiety and pupil dilation differed across age cohorts. The children exhibited resilience to the effects of math anxiety, hinting at additional influential factors such as formal math education experiences shaping their relations to mathematics and their impact on cognitive processes over time. Contrary to expectations, no significant association between self-reported math anxiety and pupil dilation during task anticipation was found in either group. In adults, math anxiety influenced pupil dilation exclusively during the initial phase of task processing indicating heightened cognitive load, but this influence diminished during sustained task processing. Theoretical implications emphasize the need for exploring individual differences, cognitive strategies, and the developmental trajectory of math anxiety in very young children.
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Ansiedad , Matemática , Pupila , Humanos , Femenino , Masculino , Ansiedad/psicología , Pupila/fisiología , Adulto , Niño , Adulto Joven , Cognición/fisiología , PreescolarRESUMEN
Intercepting moving targets is a fundamental skill in human behavior, influencing various domains such as sports, gaming, and other activities. In these contexts, precise visual processing and motor control are crucial for adapting and navigating effectively. Nevertheless, there are still some gaps in our understanding of how these elements interact while intercepting a moving target. This study explored the dynamic interplay among eye movements, pupil size, and interceptive hand movements, with visual and motion uncertainty factors. We developed a simple visuomotor task in which participants used a joystick to interact with a computer-controlled dot that moved along two-dimensional trajectories. This virtual system provided the flexibility to manipulate the target's speed and directional uncertainty during chase trials. We then conducted a geometric analysis based on optimal angles for each behavior, enabling us to distinguish between simple tracking and predictive trajectories that anticipate future positions of the moving target. Our results revealed the adoption of a strong interception strategy as participants approached the target. Notably, the onset and amount of optimal interception strategy depended on task parameters, such as the target's speed and frequency of directional changes. Furthermore, eye-tracking data showed that participants continually adjusted their gaze speed and position, continuously adapting to the target's movements. Finally, in successful trials, pupillary responses predicted the amount of optimal interception strategy while exhibiting an inverse relationship in trials without collisions. These findings reveal key interactions among visuomotor parameters that are crucial for solving complex interception tasks.
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Movimientos Oculares , Desempeño Psicomotor , Humanos , Masculino , Femenino , Desempeño Psicomotor/fisiología , Adulto , Movimientos Oculares/fisiología , Adulto Joven , Pupila/fisiología , Percepción de Movimiento/fisiología , Tecnología de Seguimiento Ocular , Mano/fisiología , Movimiento/fisiologíaRESUMEN
Pupillometry has gained attention as a valuable tool for assessing autonomic nervous system activity and studying phasic changes in pupil size to comprehend underlying neurocognitive mechanisms. However, knowledge regarding pupillary responses to social processing in autism is limited. We conducted a systematic review and meta-analysis, examining research studies on pupil size changes that compare social and non-social stimuli in autism. Electronic searches were performed for articles up to September 2023 and relevant studies were evaluated following PRISMA guidelines. Out of 284 articles screened, 14 studies were eligible for systematic review. The results indicated that non-autistic individuals showed larger pupil size for social compared to non-social stimuli (g = 0.54; 95â¯% CI [0.25, 0.82]), whereas autistic individuals seemed to exhibit no differences between the two conditions. However, high heterogeneity was observed between studies in autistic populations, compromising interpretability. Despite such limitations, pupillary responses may constitute an objective physiological marker of social processing in autism. This review emphasizes the need for further investigations into pupillary responses in autism across different life stages.
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Trastorno Autístico , Pupila , Humanos , Pupila/fisiología , Trastorno Autístico/fisiopatología , Trastorno Autístico/psicología , Percepción Social , Trastorno del Espectro Autista/fisiopatologíaRESUMEN
Caffeine is a widely used drug that broadly affects human cognition and brain function. Caffeine acts as an antagonist to the adenosine receptors in the brain. Previous anecdotal reports have also linked caffeine intake with changes in pupil diameter. By modifying the retinal irradiance, pupil diameter modulates all ocular light exposure relevant for visual (i.e., perception, detection and discrimination of visual stimuli) and non-visual (i.e., circadian) functions. To date, the extent of the influence of caffeine on pupillary outcomes, including pupil diameter, has not been examined in a systematic review. We implemented a systematic review laid out in a pre-registered protocol following PRISMA-P guidelines. We only included original research articles written in English reporting studies with human participants, in which caffeine was administered, and pupil diameter was measured using objective methods. Using broad search strategies, we consulted various databases (PsycINFO, Medline, Embase, Cochrane Library, bioRxiv and medRxiv) and used the Covidence platform to screen, review and extract data from studies. After importing studies identified through database search (n = 517 imported, n = 46 duplicates), we screened the title and abstracts (n = 471), finding 14 studies meeting our eligibility criteria. After full-text review, we excluded seven studies, leaving only a very modest number of included studies (n = 7). Extraction of information revealed that the existing literature on the effect of caffeine on pupil parameters is very heterogeneous, differing in pupil assessment methods, time of day of caffeine administration, dose, and protocol timing and design. The evidence available in the literature does not provide consistent results but studies rated as valid by quality assessment suggest a small effect of caffeine on pupil parameters. We summarize the numeric results as both differences in absolute pupil diameter and in terms of effect sizes. More studies are needed using modern pupil assessment methods, robust study design, and caffeine dose-response methodology.
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Cafeína , Pupila , Humanos , Cafeína/farmacología , Cafeína/administración & dosificación , Pupila/efectos de los fármacos , Pupila/fisiología , Estimulantes del Sistema Nervioso Central/farmacología , Estimulantes del Sistema Nervioso Central/administración & dosificaciónRESUMEN
Pupillary contagion occurs when one's pupil size unconsciously adapts to the pupil size of an observed individual and is presumed to reflect the transfer of arousal. Importantly, when estimating pupil contagion, low level stimuli properties need to be controlled for, to ensure that observations of pupillary changes are due to internal change in arousal rather than the external differences between stimuli. Here, naturalistic images of children's faces depicting either small or large pupils were presented to a group of children and adolescents with a wide range of autistic traits, a third of whom had been diagnosed with autism. We examined the extent to which pupillary contagion reflects autonomic nervous system reaction through pupil size change, heart rate and skin conductance response. Our second aim was to determine the association between arousal reaction to stimuli and degree of autistic traits. Results show that pupil contagion and concomitant heart rate change, but not skin conductance change, was evident when gaze was restricted to the eye region of face stimuli. A positive association was also observed between pupillary contagion and autistic traits when participants' gaze was constrained to the eye region. Findings add to a broader understanding of the mechanisms underlying pupillary contagion and its association with autism.
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Nivel de Alerta , Trastorno Autístico , Frecuencia Cardíaca , Pupila , Humanos , Pupila/fisiología , Masculino , Femenino , Nivel de Alerta/fisiología , Adolescente , Niño , Trastorno Autístico/fisiopatología , Frecuencia Cardíaca/fisiología , Fijación Ocular/fisiología , Respuesta Galvánica de la Piel/fisiología , Estimulación Luminosa , Sistema Nervioso Autónomo/fisiología , Sistema Nervioso Autónomo/fisiopatologíaRESUMEN
SIGNIFICANCE: This study explores the difference between cycloplegic and noncycloplegic refraction in young adult myopes. PURPOSE: From the available literature, it is unclear whether cycloplegia is necessary when refracting young adults. This study investigates the agreement between noncycloplegic autorefraction and cycloplegic autorefraction and investigates factors affecting the agreement between the two methods. METHODS: In total, 125 myopes with ages ranging between 18 and 26 years were included from Australia and Vietnam. Each participant underwent noncycloplegic autorefraction and cycloplegic autorefraction. Cycloplegia was induced with 1% ophthalmic tropicamide. RESULTS: The mean spherical equivalent difference (95% confidence interval) between noncycloplegic autorefraction and cycloplegic autorefraction was -0.20 D (-0.25 to -0.14 D; t124 = -7.18, p<0.0001 ) . A mean difference of >0.25 D was seen in 46.8% of eyes. The lower and upper limits of agreement were -0.80 and 0.41 D, respectively. With univariate analysis, factors including age, degree of refractive error, accommodation amplitude, and distance phorias showed no impact on the average difference between cycloplegic autorefraction and noncycloplegic autorefraction. Yet, eyes with near exophoria ( F2,120 = 6.63, p=0.0019) and Caucasian eyes ( F3,121 = 2.85, p=0.040) exhibited the smallest paired differences. However, in the multivariate analysis, only near exophoria was associated with a lower mean difference. A significantly smaller proportion (34.9%) of eyes with near exophoria had a paired difference of -0.25 D or more compared with esophoria (50%) and orthophoria (65%; χ2 = 6.6, p=0.038). CONCLUSIONS: Noncycloplegic autorefraction results in more myopic refractive error than cycloplegic autorefraction in young adults.
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Midriáticos , Miopía , Refracción Ocular , Tropicamida , Humanos , Refracción Ocular/fisiología , Adulto Joven , Midriáticos/administración & dosificación , Adulto , Masculino , Adolescente , Femenino , Miopía/fisiopatología , Miopía/diagnóstico , Tropicamida/administración & dosificación , Pupila/efectos de los fármacos , Pupila/fisiología , Acomodación Ocular/fisiologíaRESUMEN
OBJECTIVES: Vasospasm is a complication of aneurysmal subarachnoid hemorrhage (aSAH) that can change the trajectory of recovery and is associated with morbidity and mortality. Earlier detection of vasospasm could improve patient outcomes. Our objective is to evaluate the accuracy of smartphone-based quantitative pupillometry in the detection of radiographic vasospasm and delayed cerebral ischemia (DCI) after aSAH. MATERIALS AND METHODS: We prospectively collected pupillary light reflex (PLR) parameters from patients with aSAH admitted to a neurocritical care unit at a single hospital twice daily using quantitative smartphone pupillometry recordings. PLR parameters included: Maximum pupil diameter, minimum pupil diameter, percent change in pupil diameter, latency in beginning of pupil constriction to light, mean constriction velocity, maximum constriction velocity, and mean dilation velocity. Two-tailed t-tests for independent samples were performed to determine changes in average concurrent PLR parameter values between the following comparisons: (1) patients with and without radiographic vasospasm (defined by angiography with the need for endovascular intervention) and (2) patients with and without DCI. RESULTS: 49 subjects with aSAH underwent 323 total PLR recordings. For PLR recordings taken with (n=35) and without (n=241) radiographic vasospasm, significant differences were observed in MIN (35.0 ± 7.5 pixels with vasospasm versus 31.6 ± 6.2 pixels without; p=0.002). For PLR recordings taken with (n=43) and without (n=241) DCI, significant differences were observed in MAX (48.9 ± 14.3 pixels with DCI versus 42.5 ± 9.2 pixels without; p<0.001). CONCLUSIONS: Quantitative smartphone pupillometry has the potential to be used to detect radiographic vasospasm and DCI after aSAH.
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Valor Predictivo de las Pruebas , Reflejo Pupilar , Teléfono Inteligente , Hemorragia Subaracnoidea , Vasoespasmo Intracraneal , Humanos , Hemorragia Subaracnoidea/complicaciones , Hemorragia Subaracnoidea/fisiopatología , Hemorragia Subaracnoidea/diagnóstico , Vasoespasmo Intracraneal/etiología , Vasoespasmo Intracraneal/diagnóstico , Vasoespasmo Intracraneal/diagnóstico por imagen , Vasoespasmo Intracraneal/fisiopatología , Masculino , Persona de Mediana Edad , Femenino , Estudios Prospectivos , Anciano , Adulto , Reproducibilidad de los Resultados , Pupila/fisiología , Factores de Tiempo , Técnicas de Diagnóstico Oftalmológico/instrumentación , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/fisiopatología , Isquemia Encefálica/etiología , Isquemia Encefálica/complicacionesRESUMEN
Cerebellar brain inhibition (CBI) is an inhibitory output from the cerebellum to the primary motor cortex, which is decreased in early motor learning. Transcranial random noise stimulation (tRNS) is a noninvasive brain stimulation to induce brain plastic changes; however, the effects of cerebellar tRNS on CBI and motor learning have not been investigated yet to our knowledge. In this study, whether cerebellar tRNS decreases CBI and improves motor learning was examined, and pupil diameter was measured to examine physiological changes due to the effect of tRNS on motor learning. Thirty-four healthy subjects were assigned to either the cerebellar tRNS group or the Sham group. The subjects performed visuomotor tracking task with ten trials each in the early and late learning stages while receiving the stimulus intervention. CBI and motor evoked potentials were measured before the learning task, after the early learning stage, and after the late learning stage, and pupil diameter was measured during the task. There was no change in CBI in both groups. No group differences in motor learning rates were observed at any learning stages. Pupil diameter was smaller in the late learning stage than in the early learning stage in both groups. The cerebellar tRNS was suggested not to induce changes in CBI and improvement in motor learning, and it did not affect pupil diameter.
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Cerebelo , Potenciales Evocados Motores , Aprendizaje , Desempeño Psicomotor , Pupila , Estimulación Transcraneal de Corriente Directa , Humanos , Masculino , Femenino , Pupila/fisiología , Cerebelo/fisiología , Aprendizaje/fisiología , Adulto Joven , Adulto , Potenciales Evocados Motores/fisiología , Desempeño Psicomotor/fisiología , Inhibición Neural/fisiología , Corteza Motora/fisiologíaRESUMEN
Different empathic responses are often reported in autism but remain controversial. To investigate which component of empathy is most affected by autism, we examined the affective, cognitive, and motivational components of empathy in 25 5- to 8-year-old autistic and 27 neurotypical children. Participants were presented with visual stimuli depicting people's limbs in painful or nonpainful situations while their eye movements, pupillary responses, and verbal ratings of pain intensity and empathic concern were recorded. The results indicate an emotional overarousal and reduced empathic concern to others' pain in autism. Compared with neurotypical children, autistic children displayed larger pupil dilation accompanied by attentional avoidance to others' pain. Moreover, even though autistic children rated others in painful situations as painful, they felt less sorry than neurotypical children. Interestingly, autistic children felt more sorry in nonpainful situations compared with neurotypical children. These findings demonstrated an emotional overarousal in response to others' pain in autistic children, and provide important implications for clinical practice aiming to promote socio-emotional understanding in autistic children.
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Trastorno Autístico , Emociones , Empatía , Dolor , Humanos , Empatía/fisiología , Masculino , Niño , Femenino , Dolor/psicología , Dolor/fisiopatología , Trastorno Autístico/psicología , Trastorno Autístico/fisiopatología , Trastorno Autístico/complicaciones , Emociones/fisiología , Preescolar , Movimientos Oculares/fisiología , Pupila/fisiologíaRESUMEN
Human facial features (eyes, nose, and mouth) allow us to communicate with others. Observing faces triggers physiological responses, including pupil dilation. Still, the relative influence of social and motion content of a visual stimulus on pupillary reactivity has never been elucidated. A total of 30 adults aged 18-33 years old were recorded with an eye tracker. We analysed the event-related pupil dilation in response to stimuli distributed along a gradient of social salience (non-social to social, going from objects to avatars to real faces) and dynamism (static to micro- to macro-motion). Pupil dilation was larger in response to social (faces and avatars) compared to non-social stimuli (objects), with surprisingly a larger response for avatars. Pupil dilation was also larger in response to macro-motion compared to static. After quantifying each stimulus' real quantity of motion, we found that the higher the quantity of motion, the larger the pupil dilated. However, the slope of this relationship was not higher for social stimuli. Overall, pupil dilation was more sensitive to the real quantity of motion than to the social component of motion, highlighting the relevance of ecological stimulations. Physiological response to faces results from specific contributions of both motion and social processing.
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Reconocimiento Facial , Percepción de Movimiento , Pupila , Humanos , Pupila/fisiología , Adulto Joven , Adulto , Masculino , Femenino , Adolescente , Percepción de Movimiento/fisiología , Reconocimiento Facial/fisiología , Percepción Social , Estimulación Luminosa/métodos , Cara/fisiología , Tecnología de Seguimiento OcularRESUMEN
One mechanism by which transcranial direct current stimulation (tDCS) has been proposed to improve attention is by transcutaneous stimulation of cranial nerves, thereby activating the locus coeruleus (LC). Specifically, placement of the electrodes over the frontal bone and mastoid is thought to facilitate current flow across the face as a path of least resistance. The face is innervated by the trigeminal nerve, and the trigeminal nerve is interconnected with the LC. In this study, we tested whether stimulating the trigeminal nerve impacts indices of LC activity and performance on a sustained attention task. We replicated previous research that shows deterioration in task performance, increases in the rate of task-unrelated thoughts, and reduced pupil responses due to time on task irrespective of tDCS condition (sham, anodal, and cathodal stimulation). Importantly, tDCS did not influence pupil dynamics (pretrial or stimulus-evoked), self-reported attention state, nor task performance in active versus sham stimulation conditions. The findings reported here are consistent with theories about arousal centered on a hypothesized link between LC activity indexed by pupil size, task performance, and self-reported attention state but fail to support hypotheses that tDCS over the trigeminal nerve influences indices of LC function.
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Nivel de Alerta , Atención , Pupila , Estimulación Transcraneal de Corriente Directa , Nervio Trigémino , Humanos , Atención/fisiología , Masculino , Femenino , Adulto Joven , Nervio Trigémino/fisiología , Adulto , Nivel de Alerta/fisiología , Pupila/fisiología , Locus Coeruleus/fisiología , AdolescenteRESUMEN
BACKGROUND: Assessing refractive errors under cycloplegia is recommended for paediatric patients; however, this may not always be feasible. In these situations, refraction has to rely on measurements made under active accommodation which may increase measurements variability and error. Therefore, evaluating the accuracy and precision of non-cycloplegic refraction and biometric measurements is clinically relevant. The Myopia Master, a novel instrument combining autorefraction and biometry, is designed for monitoring refractive error and ocular biometry in myopia management. This study assessed its repeatability and agreement for autorefraction and biometric measurements pre- and post-cycloplegia. METHODS: A prospective cross-sectional study evaluated a cohort of 96 paediatric patients that underwent ophthalmologic examination. An optometrist performed two repeated measurements of autorefraction and biometry pre- and post-cycloplegia. Test-retest repeatability (TRT) was assessed as differences between consecutive measurements and agreement as differences between post- and pre-cycloplegia measurements, for spherical equivalent (SE), refractive and keratometric J0/J45 astigmatic components, mean keratometry (Km) and axial length (AL). RESULTS: Cycloplegia significantly improved the SE repeatability (TRT, pre-cyclo: 0.65 D, post-cyclo: 0.31 D). SE measurements were more repeatable in myopes and emmetropes compared to hyperopes. Keratometry (Km) repeatability did not change with cycloplegia (TRT, pre-cyclo: 0.25 D, post-cyclo:0.27 D) and AL repeatability improved marginally (TRT, pre-cyclo: 0.14 mm, post-cyclo: 0.09 mm). Regarding pre- and post-cycloplegia agreement, SE became more positive by + 0.79 D, varying with refractive error. Myopic eyes showed a mean difference of + 0.31 D, while hyperopes differed by + 1.57 D. Mean keratometry, refractive and keratometric J0/J45 and AL showed no clinically significant differences. CONCLUSIONS: Refractive error measurements, using the Myopia Master were 2.5x less precise pre-cycloplegia than post-cycloplegia. Accuracy of pre-cycloplegic refractive error measurements was often larger than the clinically significant threshold (0.25 D) and was refractive error dependent. The higher precision compared to autorefraction measurements, pre- and post-cycloplegia agreement and refractive error independence of AL measurements emphasize the superiority of AL in refractive error monitoring.
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Longitud Axial del Ojo , Biometría , Midriáticos , Miopía , Refracción Ocular , Humanos , Estudios Prospectivos , Estudios Transversales , Femenino , Masculino , Refracción Ocular/fisiología , Midriáticos/administración & dosificación , Niño , Miopía/fisiopatología , Biometría/métodos , Adolescente , Reproducibilidad de los Resultados , Pupila/efectos de los fármacos , Pupila/fisiología , Córnea/patología , Córnea/fisiopatologíaRESUMEN
PURPOSE: Positive vitreous pressure (PVP) secondary to intraoperative acute hypotony during penetrating keratoplasty can result in extrusion of the intraocular lens and vitreous. Currently described techniques are difficult or impossible to apply intraoperatively when positive vitreous pressure is noticed in an "open sky" situation after excision of the host corneal button. METHODS: We describe a technique where pupil scaffolding is used to prevent intraocular lens or crystalline lens extrusion by simply closing the pupil with a temporary suture that holds the retropupillary contents back. Once the eye is thus stabilized, the donor cornea is sutured rapidly after which the pupillary knot is cut and removed using microscissors and microforceps. RESULTS: Five patients undergoing penetrating keratoplasty under peribulbar anesthesia underwent this technique after experiencing PVP after host corneal button excision. PVP was successfully controlled in all 5 patients, and the optical grafts remained clear in the postoperative period. CONCLUSIONS: Temporary pupillary scaffolding can help control PVP and prevent ocular content extrusion during PKP surgeries.
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Queratoplastia Penetrante , Técnicas de Sutura , Cuerpo Vítreo , Humanos , Queratoplastia Penetrante/métodos , Cuerpo Vítreo/cirugía , Masculino , Femenino , Persona de Mediana Edad , Lentes Intraoculares , Pupila/fisiología , Complicaciones Intraoperatorias/prevención & control , Anciano , Iris/cirugía , AdultoRESUMEN
Self-initiated sensory action effects are widely assumed to lead to less intense perception and reduced neural responses compared to externally triggered stimuli (sensory attenuation). However, it is unclear if sensory attenuation occurs in all cases of action-effect prediction. Specifically, when predicted action-effects are relevant to determine follow-up actions attenuation could be detrimental. We quantified auditory event-related potentials (ERP) in electroencephalography (EEG) when human participants created two-sound sequences by pressing two keys on a keyboard associated with different pitch, giving rise to identity-specific action-effect prediction after the first keypress. The first sound corresponded to (congruent) or violated (incongruent) the predicted pitch and was either relevant for the selection of the second keypress to correctly complete the sequence (Relevance) or irrelevant (Control Movement), or there was only one keypress and sound (Baseline). We found a diminished P2-timed ERP component in incongruent compared to congruent trials when the sound was relevant for the subsequent action. This effect of action-effect prediction was due to an ERP reduction for incongruent relevant sounds compared to incongruent irrelevant sounds at P2 latencies and correlated negatively with modulations of pupil dilation. Contrary to our expectation, we did not observe an N1 modulation by congruency in any condition. Attenuation of the N1 component seems absent for predicted identity-specific auditory action effects, while P2-timed ERPs as well as pupil size are sensitive to predictability, at least when action effects are relevant for the selection of the next action. Incongruent relevant stimuli thereby take a special place and seem to be subject to attentional modulations and error processing.
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Electroencefalografía , Potenciales Evocados Auditivos , Pupila , Humanos , Masculino , Femenino , Potenciales Evocados Auditivos/fisiología , Adulto Joven , Adulto , Pupila/fisiología , Percepción Auditiva/fisiología , Estimulación Acústica , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiologíaRESUMEN
OBJECTIVE: Video-based eye tracking was used to investigate saccade, pupil, and blink abnormalities among patients with Huntington's disease (HD) who watched sequences of short videos. HD, an autosomal dominant neurodegenerative disorder resulting from a CAG mutation on chromosome 4, produces motor and cognitive impairments including slow or irregular eye movements, which have been studied using structured tasks. METHODS: To explore how HD affects eye movements under instruction free conditions, we assessed 22 HD patients and their age matched controls in a 10-minute video-based free viewing task. RESULTS: Patients with HD experienced a significant reduction in saccade exploration rate following video clip transitions, an increase in pupil reactions to luminance changes after clip transitions, and a significant higher blink rate throughout the task compared to the control group. CONCLUSIONS: These results show that HD has a significant impact on how patients visually explore and respond to their environment under unconstrained and ecologically natural conditions. SIGNIFICANCE: Eye tracking in HD patients revealed saccadic, pupil, and blink abnormalities in early HD patients, suggestive of brain circuitry abnormalities that probably involve brain stem deficits. Further research should explore the impact of these changes on the quality of life of the patients affected by the disease.
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Parpadeo , Enfermedad de Huntington , Pupila , Movimientos Sacádicos , Humanos , Movimientos Sacádicos/fisiología , Enfermedad de Huntington/fisiopatología , Enfermedad de Huntington/genética , Parpadeo/fisiología , Masculino , Femenino , Persona de Mediana Edad , Adulto , Pupila/fisiología , Anciano , Estimulación Luminosa/métodos , Tecnología de Seguimiento Ocular , Reflejo Pupilar/fisiologíaRESUMEN
Individuals with schizophrenia show aberrant processing of social cues. In the current study, we (1) compared trustworthiness ratings of faces between patients with schizophrenia and healthy controls, (2) compared pupillary reactivity between patients and controls (3) examined whether trustworthiness judgments in schizophrenia are related to pupil reactivity, (4) and examined associations between trustworthiness judgements and symptom severity, specifically paranoia. Patients with schizophrenia spectrum disorders (N = 48) and healthy controls (N = 33) completed a Trustworthiness Task, during which their pupil size was measured via an eye-tracking device. The mean baseline-corrected pupil size was calculated from 24 pictures of real neutral faces, each presented for 2500â¯ms. Self-reported psychotic experiences were measured by Community Assessment of Psychic Functioning (CAPE-42), and symptom severity was rated by Brief Psychiatric Rating Scale (BPRS). No group differences were found in trustworthiness ratings or pupil reactivity parameters during trustworthiness judgments. Separately, among patients, absolute difference in pupil-size change and dilation after reaching minimum size were related to more severe positive symptoms and self-reported paranoia. Our results did not show social cognitive biases in the stable outpatients with schizophrenia, or the role of pupil reactivity in trustworthiness judgments. Future studies should use longer stimuli for pupillary reactivity and control the type and dosage of utilized antipsychotic medication. Further studies are required to explore relationships in larger and more symptomatic groups of patients.
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Juicio , Pupila , Esquizofrenia , Confianza , Humanos , Masculino , Femenino , Adulto , Esquizofrenia/fisiopatología , Pupila/fisiología , Juicio/fisiología , Persona de Mediana Edad , Psicología del Esquizofrénico , Percepción Social , Reconocimiento Facial/fisiología , Adulto JovenRESUMEN
In prosopagnosia, brain lesions impair overt face recognition, but not face detection, and may coexist with residual covert recognition of familiar faces. Previous studies that simulated covert recognition in healthy individuals have impaired face detection as well as recognition, thus not fully mirroring the deficits in prosopagnosia. We evaluated a model of covert recognition based on continuous flash suppression (CFS). Familiar and unfamiliar faces and houses were masked while participants performed two discrimination tasks. With increased suppression, face/house discrimination remained largely intact, but face familiarity discrimination deteriorated. Covert recognition was present across all masking levels, evinced by higher pupil dilation to familiar than unfamiliar faces. Pupil dilation was uncorrelated with overt performance across subjects. Thus, CFS can impede overt face recognition without disrupting covert recognition and face detection, mirroring critical features of prosopagnosia. CFS could be used to uncover shared neural mechanisms of covert recognition in prosopagnosic patients and neurotypicals.
Asunto(s)
Reconocimiento Facial , Pupila , Reconocimiento en Psicología , Humanos , Reconocimiento Facial/fisiología , Adulto , Femenino , Masculino , Reconocimiento en Psicología/fisiología , Adulto Joven , Pupila/fisiología , Enmascaramiento Perceptual/fisiologíaRESUMEN
The present study explored visually induced vertical vergence (VIVV) as non-specific motion processing response. Healthy participants (7 male, mean age 28.57 ± 2.30; 9 female, mean age 27.67 ± 3.65) were exposed to optokinetic stimuli in an HTC VIVE virtual reality headset while VIVV, pupil-size, and postural sway was recorded. The methodology was shown to produce VIVV in the roll plane at 30 deg/s. Subsequent trials consisted of 40 s optokinetic motion in yaw, pitch, and roll directions at 60 deg/s, and radial optic flow; optokinetic directions were inverted after 20 s of motion. Median VIVV amplitude changes were normalized to the clockwise roll rotation, analysed, and correlated with changes in pupil-size and body sway. VIVV, pupil-size, and body sway were all affected by changes in optokinetic direction. Post-hoc analyses showed significant VIVV responses during optokinetic yaw and pitch rotations, as well as during radial optic flow stimulations. VIVV magnitudes were universally correlated with pupil-size and body sway. In conclusion, VIVV was expressed in all tested dimensions and may consequently serve as a visual motion processing biomarker. Failing to support binocularity while responding to optokinetic directionality, VIVV may reflect an eye-movement response associated with increased postural instability and stress, similar to a dorsal light reflex.
Asunto(s)
Percepción de Movimiento , Equilibrio Postural , Humanos , Masculino , Femenino , Adulto , Percepción de Movimiento/fisiología , Equilibrio Postural/fisiología , Estimulación Luminosa/métodos , Pupila/fisiología , Adulto Joven , Convergencia Ocular/fisiologíaRESUMEN
Effective attention control is essential for behavioral adaptation to different environmental contexts. In Post-traumatic Stress Disorder (PTSD) altered attention has been described in trauma-related and other emotional contexts. Nevertheless, atypical attention is also seen with neutral stimuli. The mechanisms of attention alterations in PTSD associated with neutral stimuli are poorly understood. The present study investigates alerting and orienting responses in PTSD participants using emotionally neutral stimuli in a saccade eye movement task incorporating both spatially predictable and temporally unpredictable conditions. We studied 23 PTSD patients and 27 Non-PTSD controls, using repeated-measures mixed modeling to estimate group and task condition differences in behavioral and psychophysiological measures. We explored the relationships among saccade characteristics, pupil size, and PTSD symptoms, including CAPS hypervigilance scores. PTSD, compared to Non-PTSD, participants showed differences in their saccade 'main sequence', reflected by higher peak velocities adjusted for amplitude. PTSD participants had smaller primary position errors in the unpredictable saccade condition. They also exhibited greater hyperarousal, reflected by larger pupil size during fixation that was greater in the unpredictable condition. Our results suggest that a heightened state of arousal and hypervigilance in PTSD leads to a state of atypical attention bias, even in emotionally neutral contexts. These differences may reflect higher saccade vigor. The observed differences suggest atypical attention in PTSD, which goes beyond possible distraction associated with emotional or threat-related stimuli.