Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.571
Filtrar
1.
J Cogn ; 7(1): 41, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38737819

RESUMEN

Over the past few years, several studies have explored the relationship between resting-state baseline pupil size and cognitive abilities, including fluid intelligence, working memory capacity, and attentional control. However, the results have been inconsistent. Here we present the findings from two experiments designed to replicate and expand previous research, with the aim of clarifying previous mixed findings. In both experiments, we measured baseline pupil size while participants were not engaged in any tasks, and assessed fluid intelligence using a matrix task. In one experiment we also measured working memory capacity (letter-number-sequencing task) and attentional control (attentional-capture task). We controlled for several personal and demographic variables known to influence pupil size, such as age and nicotine consumption. Our analyses revealed no relationship between resting-state pupil size (average or variability) and any of the measured constructs, neither before nor after controlling for confounding variables. Taken together, our results suggest that any relationship between resting-state pupil size and cognitive abilities is likely to be weak or non-existent.

2.
BMJ Case Rep ; 17(5)2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38782424

RESUMEN

The authors describe a case of reverse pupillary block with pigment dispersion following sequential phakic intraocular lens (pIOL) implantation for high myopia, in a young female patient. The intraocular pressure (IOP) elevation began 3 weeks postoperatively, for which Nd-YAG laser peripheral iridotomies (PIs) were attempted elsewhere. Despite maximum medical therapy, the IOP was uncontrolled. She was referred to our institute for further management. Examination showed anteriorly displaced iris-pIOL diaphragm, iris pigment dispersion and raised IOP. The PIs were incomplete. Based on clinical evaluation and investigations, we concluded that the excess area of contact of the posterior iris over the pIOL caused a reverse pupillary block and pigment dispersion. The IOPs were controlled by repeating laser iridotomies and with medical therapy. Subsequently, the patient developed a low lens vault leading to bilateral cataract. Sequential explantation of the pIOL along with cataract extraction was performed and her vision was restored.


Asunto(s)
Presión Intraocular , Implantación de Lentes Intraoculares , Lentes Intraoculares Fáquicas , Trastornos de la Pupila , Humanos , Femenino , Lentes Intraoculares Fáquicas/efectos adversos , Trastornos de la Pupila/etiología , Implantación de Lentes Intraoculares/efectos adversos , Implantación de Lentes Intraoculares/métodos , Adulto , Miopía/cirugía , Hipertensión Ocular/etiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/cirugía , Iris/cirugía , Extracción de Catarata/efectos adversos , Extracción de Catarata/métodos
3.
Sensors (Basel) ; 24(9)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38732794

RESUMEN

High-quality eye-tracking data are crucial in behavioral sciences and medicine. Even with a solid understanding of the literature, selecting the most suitable algorithm for a specific research project poses a challenge. Empowering applied researchers to choose the best-fitting detector for their research needs is the primary contribution of this paper. We developed a framework to systematically assess and compare the effectiveness of 13 state-of-the-art algorithms through a unified application interface. Hence, we more than double the number of algorithms that are currently usable within a single software package and allow researchers to identify the best-suited algorithm for a given scientific setup. Our framework validation on retrospective data underscores its suitability for algorithm selection. Through a detailed and reproducible step-by-step workflow, we hope to contribute towards significantly improved data quality in scientific experiments.


Asunto(s)
Algoritmos , Tecnología de Seguimiento Ocular , Humanos , Programas Informáticos , Exactitud de los Datos , Movimientos Oculares/fisiología , Reproducibilidad de los Resultados
5.
Neuron ; 2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38697114

RESUMEN

In the pupillary light response (PLR), increases in ambient light constrict the pupil to dampen increases in retinal illuminance. Here, we report that the pupillary reflex arc implements a second input-output transformation; it senses temporal contrast to enhance spatial contrast in the retinal image and increase visual acuity. The pupillary contrast response (PCoR) is driven by rod photoreceptors via type 6 bipolar cells and M1 ganglion cells. Temporal contrast is transformed into sustained pupil constriction by the M1's conversion of excitatory input into spike output. Computational modeling explains how the PCoR shapes retinal images. Pupil constriction improves acuity in gaze stabilization and predation in mice. Humans exhibit a PCoR with similar tuning properties to mice, which interacts with eye movements to optimize the statistics of the visual input for retinal encoding. Thus, we uncover a conserved component of active vision, its cell-type-specific pathway, computational mechanisms, and optical and behavioral significance.

6.
Neuroophthalmology ; 48(3): 193-197, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38756336

RESUMEN

Ma Huang (Ephedra), a traditional herbal remedy, which contains pseudoephedrine and ephedrine, has sympathomimetic characteristics. Despite being banned by the Federal Drug Administration in 2004, it is still used for weight loss and energy boosting in some countries. A previous healthy 42-year-old woman experienced sudden blurred vision in both eyes. Her pupils were dilated to 6 mm each, showing diminished light reflex responses, and were not responsive to both 0.1% and 1% pilocarpine. The day before the onset of her symptoms she had taken a herbal supplement. The woman's herbal medicine was believed to contain ephedrine, a component found in Ma Huang. The sympathomimetic effects of this substance could potentially induce mydriasis. After discontinuing the medication, her symptoms improved over 4 days, leading to a suspicion of drug-induced bilateral mydriasis. Herbal products prescribed for weight loss, which may contain potential elements such as Ma Huang, could lead to unforeseen side effects like bilateral mydriasis, and should be appropriately highlighted.

7.
Hear Res ; 448: 109031, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38761554

RESUMEN

In recent studies, psychophysiological measures have been used as markers of listening effort, but there is limited research on the effect of hearing loss on such measures. The aim of the current study was to investigate the effect of hearing acuity on physiological responses and subjective measures acquired during different levels of listening demand, and to investigate the relationship between these measures. A total of 125 participants (37 males and 88 females, age range 37-72 years, pure-tone average hearing thresholds at the best ear between -5.0 to 68.8 dB HL and asymmetry between ears between 0.0 and 87.5 dB) completed a listening task. A speech reception threshold (SRT) test was used with target sentences spoken by a female voice masked by male speech. Listening demand was manipulated using three levels of intelligibility: 20 % correct speech recognition, 50 %, and 80 % (IL20 %/IL50 %/IL80 %, respectively). During the task, peak pupil dilation (PPD), heart rate (HR), pre-ejection period (PEP), respiratory sinus arrhythmia (RSA), and skin conductance level (SCL) were measured. For each condition, subjective ratings of effort, performance, difficulty, and tendency to give up were also collected. Linear mixed effects models tested the effect of intelligibility level, hearing acuity, hearing asymmetry, and tinnitus complaints on the physiological reactivity (compared to baseline) and subjective measures. PPD and PEP reactivity showed a non-monotonic relationship with intelligibility level, but no such effects were found for HR, RSA, or SCL reactivity. Participants with worse hearing acuity had lower PPD at all intelligibility levels and showed lower PEP baseline levels. Additionally, PPD and SCL reactivity were lower for participants who reported suffering from tinnitus complaints. For IL80 %, but not IL50 % or IL20 %, participants with worse hearing acuity rated their listening effort to be relatively high compared to participants with better hearing. The reactivity of the different physiological measures were not or only weakly correlated with each other. Together, the results suggest that hearing acuity may be associated with altered sympathetic nervous system (re)activity. Research using psychophysiological measures as markers of listening effort to study the effect of hearing acuity on such measures are best served by the use of the PPD and PEP.

8.
J Med Internet Res ; 26: e46764, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38652534

RESUMEN

BACKGROUND: Schools in the United Kingdom and elsewhere are expected to protect and promote pupil mental health. However, many school staff members do not feel confident in identifying and responding to pupil mental health difficulties and report wanting additional training in this area. OBJECTIVE: We aimed to explore the feasibility of Kognito's At-Risk for Elementary School Educators, a brief, interactive web-based training program that uses a simulation-based approach to improve school staff's knowledge and skills in supporting pupil mental health. METHODS: We conducted a mixed methods, nonrandomized feasibility study of At-Risk for Elementary School Educators in 6 UK primary schools. Our outcomes were (1) school staff's self-efficacy and preparedness to identify and respond to pupil mental health difficulties, (2) school staff's identification of mental health difficulties and increased risk of mental health difficulties, (3) mental health support for identified pupils (including conversations about concerns, documentation of concerns, in-class and in-school support, and referral and access to specialist mental health services), and (4) the acceptability and practicality of the training. We assessed these outcomes using a series of questionnaires completed at baseline (T1), 1 week after the training (T2), and 3 months after the training (T3), as well as semistructured qualitative interviews. Following guidance for feasibility studies, we assessed quantitative outcomes across time points by comparing medians and IQRs and analyzed qualitative data using reflexive thematic analysis. RESULTS: A total of 108 teachers and teaching assistants (TAs) completed T1 questionnaires, 89 (82.4%) completed T2 questionnaires, and 70 (64.8%) completed T3 questionnaires; 54 (50%) completed all 3. Eight school staff members, including teachers, TAs, mental health leads, and senior leaders, participated in the interviews. School staff reported greater confidence and preparedness in identifying and responding to mental health difficulties after completing the training. The proportion of pupils whom they identified as having mental health difficulties or increased risk declined slightly over time (medianT1=10%; medianT2=10%; medianT3=7.4%), but findings suggested a slight increase in accuracy compared with a validated screening measure (the Strengths and Difficulties Questionnaire). In-school mental health support outcomes for identified pupils improved after the training, with increases in formal documentation and communication of concerns as well as provision of in-class and in-school support. Referrals and access to external mental health services remained constant. The qualitative findings indicated that school staff perceived the training as useful, practical, and acceptable. CONCLUSIONS: The findings suggest that brief, interactive web-based training programs such as At-Risk for Elementary School Educators are a feasible means to improve the identification of and response to mental health difficulties in UK primary schools. Such training may help address the high prevalence of mental health difficulties in this age group by helping facilitate access to care and support.


Asunto(s)
Internet , Salud Mental , Humanos , Reino Unido , Masculino , Femenino , Estudios de Factibilidad , Adulto , Encuestas y Cuestionarios , Niño , Maestros/psicología , Instituciones Académicas
9.
Trends Cogn Sci ; 28(5): 394-396, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38570252

RESUMEN

Arousal level is thought to be a key determinant of variability in cognitive performance. In a recent study, Beerendonk, Mejías et al. show that peak performance in decision-making tasks is reached at moderate levels of arousal. They also propose a neurobiologically informed computational model that can explain the inverted-U-shaped relationship.


Asunto(s)
Nivel de Alerta , Humanos , Nivel de Alerta/fisiología , Toma de Decisiones/fisiología , Cognición/fisiología
10.
J Ocul Pharmacol Ther ; 40(4): 232-239, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38621178

RESUMEN

Purpose: To assess over 2 weeks, the effect of 3 different low concentrations of atropine on pupillary diameter and accommodative amplitude in children with myopia. Methods: Fifty-eight children with myopia [spherical equivalent (SE) of -0.50 diopters (D) or worse, astigmatism of less than or equal to 2.00 D] were randomly allocated to 3 groups receiving 0.01%, 0.02%, or 0.03% atropine eye drops, once nightly for 2 weeks. The primary outcome was the change from baseline in pupillary diameter and accommodative amplitude with each of the concentrations. Results: Fifty-seven participants (114 eyes), aged between 6 and 12 years, completed the 2-week trial (mean age 9.3 ± 1.7 years and mean SE -3.53 ± 1.79 D). After 2 weeks of use, all the 3 concentrations were found to have a statistically significant effect on both the pupillary diameter and accommodative amplitude. Accommodative amplitude reduced by an average of 5.23 D, 9.28 D, and 9.32 D, and photopic pupil size increased by an average of 0.95 ± 1.05 mm, 1.65 ± 0.93 mm, and 2.16 ± 0.88 mm with 0.01%, 0.02%, and 0.03%, respectively. Of the eyes, a total of 5.3% and 5.9% of the eyes on 0.02% and 0.03% atropine had a mean residual accommodative amplitude of <5 D. The percentage of eyes having a pupillary dilation >3 mm were 4.8%, 10.5%, and 23.5% for 0.01%, 0.02%, and 0.03% atropine, respectively. Conclusions: Low-dose atropine had an effect on pupillary diameter and accommodative amplitude. With the highest concentration assessed, that is, 0.03% nearly 1 of 4 eyes had pupillary dilation of >3 mm. Clinical Trial Registration number: NCT03699423.


Asunto(s)
Acomodación Ocular , Atropina , Midriáticos , Miopía , Soluciones Oftálmicas , Pupila , Humanos , Atropina/administración & dosificación , Atropina/farmacología , Niño , Miopía/tratamiento farmacológico , Miopía/fisiopatología , Acomodación Ocular/efectos de los fármacos , Pupila/efectos de los fármacos , Masculino , Femenino , Soluciones Oftálmicas/administración & dosificación , Midriáticos/administración & dosificación , Midriáticos/farmacología , Midriáticos/uso terapéutico , Relación Dosis-Respuesta a Droga
11.
J Clin Med ; 13(5)2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38592033

RESUMEN

Background: Presbyopia is an age-related ocular condition, typically affecting individuals aged over 40 years, characterized by a gradual and irreversible decline in the eye's ability to focus on nearby objects. Correction methods for presbyopia encompass the use of corrective lenses, surgical interventions (corneal or lens based), and, more recently, the FDA-approved topical administration of 1.25% pilocarpine. While prior research has demonstrated the efficacy of daily pilocarpine eye drop application in enhancing near visual acuity by increasing the depth of focus leveraging the pinhole effect, limited knowledge exists regarding its influence on visual acuity under varying conditions of contrast and ambient luminance. Methods: This study aims to investigate the impact of these variables on visual acuity, employing the VA-CAL test, among 11 emmetropic and 11 presbyopic volunteers who reported subjective difficulties with near vision. This study includes evaluations under natural conditions with a pinhole occluder (diameter of 2 mm), and subsequent administration of 1% pilocarpine (Pilomann, Bausch + Lomb, Laval, Canada). Results: The VA-CAL results demonstrate the expected, statistically significant effects of contrast and ambient luminance on visual acuity in both emmetropic and presbyopic volunteers. Furthermore, in emmetropic individuals, the application of pilocarpine resulted in a statistically significant reduction in visual acuity. In contrast, presbyopes did not exhibit statistically significant differences in the visual acuity space under either the pinhole or pilocarpine conditions when compared to natural conditions. Conclusions: The pharmacological treatment of presbyopia with pilocarpine eye drops, intended to enhance near vision, does not adversely affect visual acuity in presbyopes. This suggests that pilocarpine may offer a viable alternative for individuals averse to wearing corrective eyewear.

12.
Clin Biomech (Bristol, Avon) ; 115: 106250, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38657356

RESUMEN

BACKGROUND: Lower limb amputation does not affect only physical and psychological functioning but the use of a prosthetic device can also lead to increased cognitive demands. Measuring cognitive load objectively is challenging, and therefore, most studies use questionnaires that are easy to apply but can suffer from subjective bias. Motivated by this, the present study investigated whether a mobile eye tracker can be used to objectively measure cognitive load by monitoring gaze behavior during a set of motor tasks. METHODS: Five prosthetic users and eight able-bodied controls participated in this study. Eye tracking data and kinematics were recorded during a set of motor tasks (level ground walking, walking on uneven terrain, obstacle avoidance, stairs up and ramp down, as well as ramp up and stairs down) while the participants were asked to focus their gaze on a visual target for as long as possible. Target fixation times and increase in pupil diameters were determined and correlated to subjective ratings of cognitive load. FINDINGS: Overall, target fixation time and pupil diameter showed strong negative and positive correlations, respectively, to the subjective rating of cognitive load in the able-bodied controls (-0.75 and 0.80, respectively). However, the individual correlation strength, and in some cases, even the sign, was different across participants. A similar trend could be observed in prosthetic users. INTERPRETATION: The results of this study showed that a mobile eye tracker may be used to estimate cognitive load in prosthesis users during locomotor tasks. This paves the way to establish a new approach to assessing cognitive load, which is objective and yet practical and simple to administer. Nevertheless, future studies should corroborate these results by comparing them to other objective measures as well as focus on translating the proposed approach outside of a laboratory.

13.
Hum Mov Sci ; 95: 103217, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38636392

RESUMEN

We found evidence that Army cadets improved their gaze behavior and performance across time under high and low pressure in a shooting task. The purpose of the study was to determine if male and female cadets developed an optimal quiet eye (QE) onset, a longer QE duration, and decreased pupil diameter variability (PDV) over time under low (LP) and high pressure (HP) conditions. The study was carried out over four sessions, with intervals of 4.5 months. During each session, 16 men and 12 women, first-year cadets of The Brazilian Army Academy, performed ten pistol shots under counterbalanced LP and HP conditions. The cadets shot in the upright position and wore an eye-tracker. Shooting accuracy improved and did not differ for men and women in the LP condition, however during HP the women performed more poorly than the men in session 1 but improved to a level similar to the men in session 4. QE duration Pre (aiming) did not differ during LP, while during HP QE Post (execution) increased across the session for men and women. QE onset 2 (execution) occurred earlier for the men than women during LP, while during HP the women improved to a level similar to the men in sessions 3 and 4. PDV declined across sessions for men and women with the lowest values in sessions 3 and 4. The findings are discussed within social facilitation theory, which states the context of training affects the rate at which improvements in motor skills occur. The results show that women cadets can improve their shooting performance, quiet eye duration, quiet eye onset and pupil diameter variability to a level similar to men if three to four LP and HP training sessions are scheduled across approximately 12-18 months.

14.
Trends Hear ; 28: 23312165241245240, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38613337

RESUMEN

Listening to speech in noise can require substantial mental effort, even among younger normal-hearing adults. The task-evoked pupil response (TEPR) has been shown to track the increased effort exerted to recognize words or sentences in increasing noise. However, few studies have examined the trajectory of listening effort across longer, more natural, stretches of speech, or the extent to which expectations about upcoming listening difficulty modulate the TEPR. Seventeen younger normal-hearing adults listened to 60-s-long audiobook passages, repeated three times in a row, at two different signal-to-noise ratios (SNRs) while pupil size was recorded. There was a significant interaction between SNR, repetition, and baseline pupil size on sustained listening effort. At lower baseline pupil sizes, potentially reflecting lower attention mobilization, TEPRs were more sustained in the harder SNR condition, particularly when attention mobilization remained low by the third presentation. At intermediate baseline pupil sizes, differences between conditions were largely absent, suggesting these listeners had optimally mobilized their attention for both SNRs. Lastly, at higher baseline pupil sizes, potentially reflecting overmobilization of attention, the effect of SNR was initially reversed for the second and third presentations: participants initially appeared to disengage in the harder SNR condition, resulting in reduced TEPRs that recovered in the second half of the story. Together, these findings suggest that the unfolding of listening effort over time depends critically on the extent to which individuals have successfully mobilized their attention in anticipation of difficult listening conditions.


Asunto(s)
Esfuerzo de Escucha , Pupila , Adulto , Humanos , Relación Señal-Ruido , Habla
15.
Sensors (Basel) ; 24(8)2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38676162

RESUMEN

Pupil size is a significant biosignal for human behavior monitoring and can reveal much underlying information. This study explored the effects of task load, task familiarity, and gaze position on pupil response during learning a visual tracking task. We hypothesized that pupil size would increase with task load, up to a certain level before decreasing, decrease with task familiarity, and increase more when focusing on areas preceding the target than other areas. Fifteen participants were recruited for an arrow tracking learning task with incremental task load. Pupil size data were collected using a Tobii Pro Nano eye tracker. A 2 × 3 × 5 three-way factorial repeated measures ANOVA was conducted using R (version 4.2.1) to evaluate the main and interactive effects of key variables on adjusted pupil size. The association between individuals' cognitive load, assessed by NASA-TLX, and pupil size was further analyzed using a linear mixed-effect model. We found that task repetition resulted in a reduction in pupil size; however, this effect was found to diminish as the task load increased. The main effect of task load approached statistical significance, but different trends were observed in trial 1 and trial 2. No significant difference in pupil size was detected among the three gaze positions. The relationship between pupil size and cognitive load overall followed an inverted U curve. Our study showed how pupil size changes as a function of task load, task familiarity, and gaze scanning. This finding provides sensory evidence that could improve educational outcomes.


Asunto(s)
Tecnología de Seguimiento Ocular , Pupila , Humanos , Pupila/fisiología , Masculino , Femenino , Adulto , Adulto Joven , Fijación Ocular/fisiología , Movimientos Oculares/fisiología
16.
Sensors (Basel) ; 24(8)2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38676165

RESUMEN

In this paper, the implementation of a new pupil detection system based on artificial intelligence techniques suitable for real-time and real-word applications is presented. The proposed AI-based pupil detection system uses a classifier implemented with slim-type neural networks, with its classes being defined according to the possible positions of the pupil within the eye image. In order to reduce the complexity of the neural network, a new parallel architecture is used in which two independent classifiers deliver the pupil center coordinates. The training, testing, and validation of the proposed system were performed using almost 40,000 eye images with a resolution of 320 × 240 pixels and coming from 20 different databases, with a high degree of generality. The experimental results show a detection rate of 96.29% at five pixels with a standard deviation of 3.38 pixels for all eye images from all databases and a processing speed of 100 frames/s. These results indicate both high accuracy and high processing speed, and they allow us to use the proposed solution for different real-time applications in variable and non-uniform lighting conditions, in fields such as assistive technology to communicate with neuromotor-disabled patients by using eye typing, in computer gaming, and in the automotive industry for increasing traffic safety by monitoring the driver's cognitive state.


Asunto(s)
Inteligencia Artificial , Redes Neurales de la Computación , Pupila , Humanos , Pupila/fisiología , Algoritmos , Procesamiento de Imagen Asistido por Computador/métodos , Bases de Datos Factuales
17.
Auton Neurosci ; 253: 103179, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38677128

RESUMEN

Unilateral nociceptive stimulation is associated with subtle signs of pupil asymmetry that may reflect lateralized activity in the locus coeruleus. To explore drivers of this pupil asymmetry, electrical stimuli, delivered alone or 200 ms before or after an acoustic startle stimulus, were administered to one ankle under four experimental conditions: with or without a 1.6 s anticipatory period, or while the forearm ipsilateral or contralateral to the electrical stimulus was heated tonically to induce moderate pain (15 healthy participants in each condition). Pupil diameter was measured at the start of each trial, at stimulus delivery, and each second for 5 s after stimulus delivery. At the start of the first trial, the pupil ipsilateral to the side on which electric shocks were later delivered was larger than the contralateral pupil. Both pupils dilated robustly during the anticipatory period and dilated further during single- and dual-stimulus trials. However, pupil asymmetry persisted throughout the experiment. Tonically-applied forearm heat-pain modulated the pupillary response to phasic electrical stimuli, with a slight trend for dilatation to be greater contralateral to the forearm being heated. Together, these findings suggest that focusing anxiously on the expected site of noxious stimulation was associated with dilatation of the ipsilateral pupil whereas phasic nociceptive stimuli and psychological arousal triggered bilateral pupillary dilatation. It was concluded that preparatory cognitive activity rather than phasic afferent nociceptive input is associated with pupillary signs of lateralized activity in the locus coeruleus.

18.
Cell Rep ; 43(4): 114081, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38581682

RESUMEN

Narratives can synchronize neural and physiological signals between individuals, but the relationship between these signals, and the underlying mechanism, is unclear. We hypothesized a top-down effect of cognition on arousal and predicted that auditory narratives will drive not only brain signals but also peripheral physiological signals. We find that auditory narratives entrained gaze variation, saccade initiation, pupil size, and heart rate. This is consistent with a top-down effect of cognition on autonomic function. We also hypothesized a bottom-up effect, whereby autonomic physiology affects arousal. Controlled breathing affected pupil size, and heart rate was entrained by controlled saccades. Additionally, fluctuations in heart rate preceded fluctuations of pupil size and brain signals. Gaze variation, pupil size, and heart rate were all associated with anterior-central brain signals. Together, these results suggest bidirectional causal effects between peripheral autonomic function and central brain circuits involved in the control of arousal.


Asunto(s)
Encéfalo , Frecuencia Cardíaca , Humanos , Encéfalo/fisiología , Femenino , Masculino , Frecuencia Cardíaca/fisiología , Adulto , Pupila/fisiología , Adulto Joven , Nivel de Alerta/fisiología , Percepción Auditiva/fisiología , Movimientos Sacádicos/fisiología , Cognición/fisiología , Sistema Nervioso Autónomo/fisiología , Estimulación Acústica
19.
Front Neurol ; 15: 1363190, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38654735

RESUMEN

Introduction: The pupillary light reflex (PLR) is the constriction of the pupil in response to light. The PLR in response to a pulse of light follows a complex waveform that can be characterized by several parameters. It is a sensitive marker of acute neurological deterioration, but is also sensitive to the background illumination in the environment in which it is measured. To detect a pathological change in the PLR, it is therefore necessary to separate the contributions of neuro-ophthalmic factors from ambient illumination. Illumination varies over several orders of magnitude and is difficult to control due to diurnal, seasonal, and location variations. Methods and results: We assessed the sensitivity of seven PLR parameters to differences in ambient light, using a smartphone-based pupillometer (AI Pupillometer, Solvemed Inc.). Nine subjects underwent 345 measurements in ambient conditions ranging from complete darkness (<5 lx) to bright lighting (≲10,000 lx). Lighting most strongly affected the initial pupil size, constriction amplitude, and velocity. Nonlinear models were fitted to find the correction function that maximally stabilized PLR parameters across different ambient light levels. Next, we demonstrated that the lighting-corrected parameters still discriminated reactive from unreactive pupils. Ten patients underwent PLR testing in an ophthalmology outpatient clinic setting following the administration of tropicamide eye drops, which rendered the pupils unreactive. The parameters corrected for lighting were combined as predictors in a machine learning model to produce a scalar value, the Pupil Reactivity (PuRe) score, which quantifies Pupil Reactivity on a scale 0-5 (0, non-reactive pupil; 0-3, abnormal/"sluggish" response; 3-5, normal/brisk response). The score discriminated unreactive pupils with 100% accuracy and was stable under changes in ambient illumination across four orders of magnitude. Discussion: This is the first time that a correction method has been proposed to effectively mitigate the confounding influence of ambient light on PLR measurements, which could improve the reliability of pupillometric parameters both in pre-hospital and inpatient care settings. In particular, the PuRe score offers a robust measure of Pupil Reactivity directly applicable to clinical practice. Importantly, the formulae behind the score are openly available for the benefit of the clinical research community.

20.
Curr Biol ; 34(8): 1605-1620.e5, 2024 04 22.
Artículo en Inglés | MEDLINE | ID: mdl-38492568

RESUMEN

Sound elicits rapid movements of muscles in the face, ears, and eyes that protect the body from injury and trigger brain-wide internal state changes. Here, we performed quantitative facial videography from mice resting atop a piezoelectric force plate and observed that broadband sounds elicited rapid and stereotyped facial twitches. Facial motion energy (FME) adjacent to the whisker array was 30 dB more sensitive than the acoustic startle reflex and offered greater inter-trial and inter-animal reliability than sound-evoked pupil dilations or movement of other facial and body regions. FME tracked the low-frequency envelope of broadband sounds, providing a means to study behavioral discrimination of complex auditory stimuli, such as speech phonemes in noise. Approximately 25% of layer 5-6 units in the auditory cortex (ACtx) exhibited firing rate changes during facial movements. However, FME facilitation during ACtx photoinhibition indicated that sound-evoked facial movements were mediated by a midbrain pathway and modulated by descending corticofugal input. FME and auditory brainstem response (ABR) thresholds were closely aligned after noise-induced sensorineural hearing loss, yet FME growth slopes were disproportionately steep at spared frequencies, reflecting a central plasticity that matched commensurate changes in ABR wave 4. Sound-evoked facial movements were also hypersensitive in Ptchd1 knockout mice, highlighting the use of FME for identifying sensory hyper-reactivity phenotypes after adult-onset hyperacusis and inherited deficiencies in autism risk genes. These findings present a sensitive and integrative measure of hearing while also highlighting that even low-intensity broadband sounds can elicit a complex mixture of auditory, motor, and reafferent somatosensory neural activity.


Asunto(s)
Audición , Animales , Ratones , Masculino , Audición/fisiología , Sonido , Estimulación Acústica , Femenino , Corteza Auditiva/fisiología , Ratones Endogámicos C57BL , Movimiento , Potenciales Evocados Auditivos del Tronco Encefálico
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...