Pupillary Response Research Articles

Multi-level processing of emotions in life motion signals revealed through pupil responses

Perceiving emotions from the movements of other biological entities is critical for human survival and interpersonal interactions. Here, we report that emotional information conveyed by point-light biological motion (BM) triggered automatic physiological responses as reflected in pupil size. Specifically, happy BM evoked larger pupil size than neutral and sad BM, while sad BM induced a smaller pupil response than neutral BM. Moreover, this happy over sad pupil dilation effect is negatively correlated with individual autistic traits. Notably, emotional BM with only local motion features retained could also exert modulations on pupils. Compared with intact BM, both happy and sad local BM evoked stronger pupil responses than neutral local BM starting from an earlier time point, with no difference between the happy and sad conditions. These results revealed a fine-grained pupil-related emotional modulation induced by intact BM and a coarse but rapid modulation by local BM, demonstrating multi-level processing of emotions in life motion signals. Taken together, our findings shed new light on BM emotion processing, and highlight the potential of utilizing the emotion-modulated pupil response to facilitate the diagnosis of social cognitive disorders.

Multi-level processing of emotions in life motion signals revealed through pupil responses.

Perceiving emotions from the movements of other biological entities is critical for human survival and interpersonal interactions. Here, we report that emotional information conveyed by point-light biological motion (BM) triggered automatic physiological responses as reflected in pupil size. Specifically, happy BM evoked larger pupil size than neutral and sad BM, while sad BM induced a smaller pupil response than neutral BM. Moreover, this happy over sad pupil dilation effect is negatively correlated with individual autistic traits. Notably, emotional BM with only local motion features retained could also exert modulations on pupils. Compared with intact BM, both happy and sad local BM evoked stronger pupil responses than neutral local BM starting from an earlier time point, with no difference between the happy and sad conditions. These results revealed a fine-grained pupil-related emotional modulation induced by intact BM and a coarse but rapid modulation by local BM, demonstrating multi-level processing of emotions in life motion signals. Taken together, our findings shed new light on BM emotion processing, and highlight the potential of utilizing the emotion-modulated pupil response to facilitate the diagnosis of social cognitive disorders.

Hearing Impairment: Reduced Pupil Dilation Response and Frontal Activation During Degraded Speech Perception.

A relevant aspect of listening is the effort required during speech processing, which can be assessed by pupillometry. Here, we assessed the pupil dilation response of normal-hearing (NH) and hard of hearing (HH) individuals during listening to clear sentences and masked or degraded sentences. We combined this assessment with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of the pupil dilation response. Seventeen NH participants (Mage = 46 years) were compared to 17 HH participants (Mage = 45 years) who were individually matched in age and educational level. Participants repeated sentences that were presented clearly, that were distorted, or that were masked. The sentence intelligibility level of masked and distorted sentences was 50% correct. Silent baseline trials were presented as well. Performance measures, pupil dilation responses, and fMRI data were acquired. HH individuals had overall poorer speech reception than the NH participants, but not for noise-vocoded speech. In addition, an interaction effect was observed with smaller pupil dilation responses in HH than in NH listeners for the degraded speech conditions. Hearing impairment was associated with higher activation across conditions in the left superior temporal gyrus, as compared to the silent baseline. However, the region of interest analysis indicated lower activation during degraded speech relative to clear speech in bilateral frontal regions and the insular cortex, for HH compared to NH listeners. Hearing impairment was also associated with a weaker relation between the pupil response and activation in the right inferior frontal gyrus. Overall, degraded speech evoked higher frontal activation than clear speech. Brain areas associated with attentional and cognitive-control processes may be increasingly recruited when speech is degraded and are related to the pupil dilation response, but this relationship is weaker in HH listeners. https://doi.org/10.23641/asha.27162135.

Idiosyncratic pupil regulation in autistic children.

Recent neuroimaging and eye-tracking studies have suggested that children with autism exhibit more variable and idiosyncratic brain responses and eye movements than typically developing (TD) children. Here, we extended this research to pupillometry recordings. We successfully acquired pupillometry recordings from 111 children (74 with autism), 4.5-years-old on average, who viewed three 90 s movies, twice. We extracted their pupillary time-course for each movie, capturing their stimulus evoked pupillary responses. We then computed the correlation between the time-course of each child and those of all others in their group as well as between each autistic child and all children in the TD group. This yielded an average inter-subject correlation value per child, representing how similar their pupillary responses were to all others in their group or the comparison group. Children with autism exhibited significantly weaker inter-subject correlations than TD children in all comparisons. These differences were independent of previously reported differences in gaze inter-subject correlations and were largest in responses to a naturalistic movie containing footage of a social interaction between two TD children. The results demonstrate the utility of measuring the idiosyncrasy of pupil regulation, which can be performed with passive viewing of movies even by young children with co-occurring intellectual disability. These findings reveal that a considerable number of children with autism have significantly less stable, idiosyncratic pupil regulation than TD children, indicative of more variable, weakly regulated, underlying neural activity.

Attenuated melanopsin-mediated post-illumination pupillary response (PIPR) is associated with reduced actigraphic amplitude and mesor in older adults.

This study aimed to explore the relationship between post-illumination pupillary response (PIPR) with sleep and circadian measures in a community sample of healthy older adults. Eligible participants were invited to complete a one-week sleep diary, actigraphy and provide an overnight urine sample to measure urinary 6-sulfatoxymelatonin (aMT6s). PIPR was defined as the as the pupil constriction at 6s post-stimulus (PIPR-6s), and ii) for 30s beginning 10s after stimulus (PIPR-30s) normalized as a percentage to the baseline pupil diameter, after 1s of blue and 1s of red-light stimulus, respectively. The Net-PIPRs were reported by subtracting the PIPR to red stimulus from the PIPR to blue stimulus. The relationship between PIPR metrics to aMT6s and actigraphic rest-activity rhythm parameters was examined by generalized linear models. A total of 48 participants were recruited (Mean age: 62.6 ± 7.1 years, Male: 44%). Both Net PIPR-6s and Net PIPR-30s were significantly associated with actigraphic rest-activity amplitude (B=0.03, p=0.001 and B=0.03, p=0.01, respectively), and actigraphic rest-activity mesor (B=0.02, p=0.001 and B=0.03, p=0.004, respectively). Additionally, the Net PIPR-30s were positively associated with overnight aMT6s level (B=0.04, p=0.03), and negatively associated with actigraphic rest-activity acrophase (B=-0.01, p=0.004) in the fully adjusted models. Attenuated PIPR is associated with a reduced actigraphic amplitude and mesor. The reduced retinal light responsivity may be a potential pathway contributing to impaired photic input to the circadian clock and resulted in the age-related circadian changes in older adults.

Implication of Parental Engagement to the Students in Home-School Learning

Parental involvement in home-school learning also helps to strengthen the relationship, fosters greater autonomy and responsibility in children, and flexible learning experiences. This study used a descriptive-phenomenological study that divulged the context of home-school learning during the health crisis brought by COVID-19 among elementary pupils. Ten (10) Grade 4 pupils, currently enrolled in S.Y. 2021-2022 and who had been studying both before and during the pandemic, participated in the interview. Colaizzi's data analysis approach was later used to analyze the interview data. Findings indicated that elementary pupils have a variety of experiences in home-school learning and are also experiencing challenges in home-school learning. The study's findings also revealed the role of their parents during home-school learning by giving them a lot of time teaching the reading and constant follow-ups with their children. The different challenges and experiences in home-school learning were evident in the pupil's responses. Hence, the result of the study also revealed that the pupils had difficulty in reading and writing during home-school learning. Students can benefit from parental support and guidance, which can improve their motivation, attitudes, and communication skills.

Pupillary responses to directional uncertainty while intercepting a moving target.

Pupillary responses serve as sensitive indicators of cognitive processes, attentional shifts and decision-making dynamics. Our study investigates how directional uncertainty and target speed (V T) influence pupillary responses in a foveal tracking task involving the interception of a moving dot. Directional uncertainty, reflecting the unpredictability of the target's direction changes, was manipulated by altering the angular range (AR) from which random directions for the moving dot were extracted. Higher AR values were associated with reduced pupillary diameters, indicating that heightened uncertainty led to smaller pupil sizes. Additionally, an inverse U-shaped relationship between V T and pupillary responses suggested maximal diameters at intermediate speeds. Analysis of saccade-triggered responses showed a negative correlation between pupil diameter and directional uncertainty. Dynamic linear modelling revealed the influence of past successful collisions and other behavioural parameters on pupillary responses, emphasizing the intricate interaction between task variables and cognitive processing. Our results highlight the dynamic interplay between the directional uncertainty of a single moving target, V T and pupillary responses, with implications for understanding attentional mechanisms, decision-making processes and potential applications in emerging technologies.

Optimizing Traumatic Brain Injury Recovery: Exploring the Advantages and Results of Decompressive Craniectomy.

Traumatic brain injury (TBI) causes significant mortality and morbidity across regions, imposing a substantial socioeconomic burden on societies. A major complication that can arise is uncontrolled intracranial pressure (ICP). Several strategies exist for reducing ICP in TBI patients, including head elevation, mannitol administration, and hyperventilation. Decompressive craniectomy (DC) is a therapeutic approach employed to lower ICP. This technique offers immediate and permanent relief from elevated ICP, although there are ongoing debates regarding its beneficial use and appropriate indications for patients with increased ICP. The objective of this review was to assess variations in surgical technique, timing of the procedure, and patient characteristics associated with DC. Through the evaluation of clinical and radiologic data concerning DC in patients with elevated ICP, it was revealed that while DC provides numerous benefits, it also carries a significant risk of mortality and morbidity. Furthermore, we observed that factors such as age, initial Glasgow Coma Scale (GCS) score, pupil response, and the time interval between injury and DC can serve as predictors for the procedure's outcomes. Based on our findings, we recommend conducting further trials to shed light on the use of DC in TBI patients.

Local anaesthetic delivery through indwelling retrobulbar catheters for ocular pain control in horses

AbstractBackgroundEquine corneal disease is common and painful. Current pain mitigation strategies are often suboptimal, especially early in the disease.ObjectivesTo evaluate the effects of local anaesthetic delivery via indwelling retrobulbar catheter on corneal sensitivity, pupil size, pupillary light responses (PLRs), and ocular motility in normal horses.Study designRandomised, controlled crossover experiment.MethodsOne eye was randomly selected from seven horses. A 20‐gauge catheter was placed in the retrobulbar space and injected with 10 mL of 0.5% bupivacaine or 0.9% saline. Cochet–Bonnet esthesiometry (CBE), pupil photogrammetry, PLRs, and oculocephalic reflexes were evaluated before injection (t = 0) and t = 0.25, 1, 3, 6, 9 and 12 h after injection. Following a 7–14 day washout period, this procedure was repeated using the alternative injection solution. Corneal touch thresholds (CTTs) derived from CBE and pupillary areas (PA; as measured from photographs) were compared across time for each group. PLRs and oculocephalic reflexes were compared between groups at each evaluation time point.ResultsSaline did not affect CBE, PA, PLRs or oculocephalic reflexes at any time point. Bupivacaine reduced CTT compared with saline for 6 h, with maximum reduction at t = 1 h (bupivacaine: 0.08 ± 0.20 cm; saline: 4.21 ± 0.39 cm; p < 0.001). Bupivacaine increased PA compared with saline for 3 h, with maximum increase at t = 3 h (bupivacaine: 349.75 ± 84.80 mm2; saline: 194.65 ± 27.03 mm2; p = 0.04). Bupivacaine injection reduced PLRs for 9 h and oculocephalic reflexes for 3 h; saline had no effect. Mild adverse effects included chemosis, blepharoedema, and transiently reduced palpebral reflex.Main limitationsReduction in CTT may not directly translate to pain control in clinical horses with corneal disease. Adverse effects of repeated injections were not evaluated.ConclusionsInjection of bupivacaine via an indwelling retrobulbar catheter in horses reduces corneal sensitivity and may be useful in reducing pain in horses with corneal disease.

Tunnel motion: Pupil dilations to optic flow within illusory dark holes.

We showed to the same observers both dynamic and static 2D patterns that can both evoke distinctive perceptions of motion or optic flow, as if moving in a tunnel or into a dark hole. At all times pupil diameters were monitored with an infrared eye tracker. We found a converging set of results indicating stronger pupil dilations to expansive growth of shapes or optic flows evoking a forward motion into a dark tunnel. Multiple regression analyses showed that the pupil responses to the illusory expanding black holes of static patterns were predicted by the individuals' pupil response to optic flows showing spiraling motion or "free fall" into a black hole. Also, individuals' pupil responses to spiraling motion into dark tunnels predicted the individuals' sense of illusory expansion with the static, illusory expanding, dark holes. This correspondence across individuals between their pupil responses to both dynamic and static, illusory expanding, holes suggests that these percepts reflect a common perceptual mechanism, deriving motion from 2D scenes, and that the observers' pupil adjustments reflect the direction and strength of motion they perceive and the expected outcome of an increase in darkness.

Orbital Hematoma Treatment—A Retrospective Study

Background: Bleeding within the orbit in the form of a subperiosteal or retrobulbar hematoma is a relatively common complication of trauma and surgery. It affects up to 30% of patients fractures involving the orbital bones. Most cases do not require surgical intervention because they do not cause retinal ischemia or optic nerve neuropathy. The above symptoms occur in only 0.5–1% of patients developing Orbital Compartment Syndrome (OCS). Due to the short period (60–100 min) of time in which the optic nerve and retina can tolerate increased intraocular pressure, it seemed reasonable to evaluate and standardize the surgical management protocol for this rare complication. Objective: The aim of this retrospective study was to retrospectively analyze cases of inframammary haematomas with clinically relevant correlations. Methods: Eighteen patients treated at the Department of Maxillofacial Surgery due to OCS, in Lodz and Poznan, Poland, between 2009 and 2022, were included. APTT, INR, systemic diseases, cause, location and size of hematoma, presence and number of fractures, visual disturbances and pupillary response on the day after surgery and one month after, the type of intervention and time between admission to the hospital and surgery were evaluated. Results: Statistically significant correlations were obtained between the size of the hematoma and the patients’ age, the degree of visual disturbance and the weakening of pupillary constriction, severe initial symptoms and poor postoperative outcomes at both postoperative periods studied, immediate and distant poor outcome after decompression surgery and good postoperative outcome persisting one month after. Conclusions: The results obtained in the study and the surgical protocol proposed by the authors are in line with the current state of knowledge regarding orbital hematomas. Some of the correlations described in the literature (such as OCS and anticoagulant treatment) were not demonstrated, but this is probably due to the small study group. Maintaining the 100 min limit as a standard was possible only in early postoperative diagnoses (only 1 of the patients was operated on up to 100 min after the appearance of symptoms). In other cases, the specialized diagnosis took an average of 2785 ± 4020 min or 46 ± 67 h.

Individual differences in belief updating and phasic arousal are related to psychosis proneness

Many decisions entail the updating of beliefs about the state of the environment by accumulating noisy sensory evidence. This form of probabilistic reasoning may go awry in psychosis. Computational theory shows that optimal belief updating in environments subject to hidden changes in their state requires a dynamic modulation of the evidence accumulation process. Recent empirical findings implicate transient responses of pupil-linked central arousal systems to individual evidence samples in this modulation. Here, we analyzed behavior and pupil responses during evidence accumulation in a changing environment in a community sample of human participants. We also assessed their subclinical psychotic experiences (psychosis proneness). Participants most prone to psychosis showed overall less flexible belief updating profiles, with diminished behavioral impact of evidence samples occurring late during decision formation. These same individuals also exhibited overall smaller pupil responses and less reliable pupil encoding of computational variables governing the dynamic belief updating. Our findings provide insights into the cognitive and physiological bases of psychosis proneness and open paths to unraveling the pathophysiology of psychotic disorders.

Pupillary dilation response to the auditory food words in adolescents with obesity without binge eating disorder

Childhood obesity is a growing global public health problem. Studies suggest that environmental cues contribute to developing and maintaining obesity. We aimed to evaluate pupillary changes to auditory food words vs. nonfood words and to conduct a dynamic temporal analysis of pupil size changes in adolescents with obesity without binge eating disorder by comparing healthy-weight adolescents. In this study, a total of 63 adolescents aged 12–18 years (n = 32, obesity group (OG); n = 31, control group (CG)) were included. In an auditory paradigm, participants were presented with a series of high and low-calorie food and nonfood words. A binocular remote eye-tracking device was used to measure pupil diameter. Generalized additive mixed models (GAMMs) were used for dynamic temporal analysis of pupillometry data. The results of GAMM analysis indicated that CG had larger pupil dilation than the OG while listening to auditory food words. CG had larger pupil dilation in food words than in nonfood words. However, the OG had a similar pupillary response in food and nonfood words. Pupil dilation response to higher-calorie foods was extended over the later stages of the time period (after 2000 ms) in the OG. In summary, our findings indicated that individuals with obesity had lower pupil dilation to auditory food words compared to normal-weight peers. Adolescents with obesity had prolonged pupillary dilation in higher calories of food words. The individual psychological factors affecting the dynamic changes of pupil responses to food cues in adolescents with obesity should be examined in further studies.

The effects of emotional arousal on pupil size depend on luminance

Pupillometry is widely used to measure arousal states. The primary functional role of the pupil, however, is to respond to the luminance of visual inputs. We previously demonstrated that cognitive effort-related arousal interacted multiplicatively with luminance, with the strongest pupillary effects of arousal occurring at low-to-mid luminances (< 37 cd/m2), implying a narrow range of conditions ideal for assessing cognitive arousal-driven pupillary differences. Does this generalize to other forms of arousal? To answer this, we assessed luminance-driven pupillary response functions while manipulating emotional arousal, using well-established visual and auditory stimulus sets. At the group level, emotional arousal interacted with the pupillary light response differently from cognitive arousal: the effects occurred primarily at much lower luminances (< 20 cd/m2). Analyses at the individual-participant level revealed qualitatively distinct patterns of modulation, with a sizable number of individuals displaying no arousal response to the visual or auditory stimuli, regardless of luminance. Together, our results suggest that effects of arousal on pupil size are not monolithic: different forms of arousal exert different patterns of effects. More practically, our findings suggest that lower luminances create better conditions for measuring pupil-linked arousal, and when selecting ambient luminance levels, consideration of the arousal manipulation and individual differences is critical.

Ocular Accommodative and Pupillary Responses During Fixation on Augmented Reality With a Maxwellian Display.

This study aimed to investigate the changes in ocular refraction and pupillary diameter during fixation on augmented reality (AR) images using a Maxwellian display. Twenty-two healthy young volunteers (average age, 20.7 ± 0.5 years) wore a Maxwellian display device in front of their right eye and fixated on an asterisk displayed on both a liquid-crystal display (real target) and a Maxwellian display (AR target) for 29 seconds (real as a baseline for 3 seconds, AR for 13 seconds, and real for 13 seconds) at distances of 5.0, 0.5, 0.33, and 0.2 meters. A binocular open-view autorefractometer was used to measure the ocular refraction and pupillary diameter of the left eye. Accommodative (5.0 meters, 0.28 ± 0.29 diopter [D]; 0.5 meter, -0.12 ± 0.35 D; 0.33 meter, -0.43 ± 0.57 D; 0.2 meter, -1.20 ± 0.82 D) and pupillary (5.0 meters, 0.07 ± 0.22 mm; 0.5 meter, -0.08 ± 0.17 mm; 0.33 meter, -0.16 ± 0.20 mm; 0.2 meter, -0.25 ± 0.24 mm) responses were negative when the real target distances were farther away. The accommodative response was significantly and positively correlated with the pupillary response during fixation on the AR target (R2 = 0.187, P < 0.001). Fixating on AR images using a Maxwellian display induces accommodative and pupillary responses. Accommodative responses depend on the distance between real objects. Overall, the Maxwellian display does not completely eliminate accommodation in real space.

Diagnostic performance of pupil perimetry in detecting hemianopia under standard and virtual reality viewing conditions.

To determine the diagnostic performance and reliability of two pupil perimetry (PP) methods in homonymous hemianopia. This cross-sectional monocenter cohort study performed gaze-contingent flicker PP (gcFPP) and a virtual reality version of gcFPP (VRgcFPP) twice on separate occasions in all patients suffering from homonymous hemianopia due to neurological impairment. The main outcomes were (1) test accuracy and (2) test-retest reliability: (1) was measured through area under the receiver operating characteristics curve (AUC) calculation of (VR)gcFPP results with comparators being SAP and healthy controls, respectively; (2) was evaluated by comparing tests 1 and 2 of both methods within patients. Both gcFPP and VRgcFPP were performed in 15 patients (12 males, MAge = 57, SDAge = 15) and 17 controls (6 males, MAge = 53, SDAge = 12). Mean test accuracy was good in separating damaged from intact visual field regions (gcFPP: Mauc = 0.83, SDauc = 0.09; VRgcFPP: Mauc = 0.69,SDauc = 0.13) and in separating patients from controls (gcFPP: Mauc = 0.92,SDauc = 0.13; VRgcFPP: Mauc = 0.96,SDauc = 0.15). A high test-retest reliability was found for the proportion intact versus damaged visual field (gcFPP: r = 0.95, P < .001, VRgcFPP: r = 1.00, P < .001). Overall, these results can be summarized as follows: (1) the comparison of pupil response amplitudes between intact versus damaged regions per patient indicate that gcFPP allows for cleaner imaging of intact versus damaged visual field regions than VRgcFPP, (2) the comparisons of average differences in intact versus damaged amplitudes between patients and controls demonstrate high diagnostic performance of both gcFPP and VRgcFPP, and (3) the test-retest reliabilities confirm that both gcFPP and VRgcFPP reliably and consistently measure defects in homonymous hemianopia. KEY MESSAGES: What is known Standard automated perimetry is the current gold standard for visual field examination, but not always suited for the evaluation of the VF in neurologically impaired patients. Pupil perimetry consists of the measurement of pupillary responses to light stimuli as a measure of visual sensitivity. What is new This study reports the highest diagnostic accuracy of pupil perimetry so far in patients with homonymous hemianopia. Gaze-contingent flicker pupil perimetry reliably and consistently measures defects in homonymous hemianopia under standard and virtual reality viewing conditions.

Visuomotor predictors of interception.

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.

Pupillary Response in Visual Imagery

Pupillary Response in Visual Imagery

How do pupillary light responses and microsaccades allude to voluntary and involuntary auditory attention?

How do pupillary light responses and microsaccades allude to voluntary and involuntary auditory attention?

Deconstructing the task-evoked pupillary response

Deconstructing the task-evoked pupillary response