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Annual Review of Vision Science Sep 2020The pupil responds reflexively to changes in brightness and focal distance to maintain the smallest pupil (and thus the highest visual acuity) that still allows... (Review)
Review
The pupil responds reflexively to changes in brightness and focal distance to maintain the smallest pupil (and thus the highest visual acuity) that still allows sufficient light to reach the retina. The pupil also responds to a wide variety of cognitive processes, but the functions of these cognitive responses are still poorly understood. In this review, I propose that cognitive pupil responses, like their reflexive counterparts, serve to optimize vision. Specifically, an emphasis on central vision over peripheral vision results in pupil constriction, and this likely reflects the fact that central vision benefits most from the increased visual acuity provided by small pupils. Furthermore, an intention to act with a bright stimulus results in preparatory pupil constriction, which allows the pupil to respond quickly when that bright stimulus is subsequently brought into view. More generally, cognitively driven pupil responses are likely a form of sensory tuning: a subtle adjustment of the eyes to optimize their properties for the current situation and the immediate future.
Topics: Pupil; Retina; Vision, Ocular; Visual Acuity; Visual Perception
PubMed: 32432993
DOI: 10.1146/annurev-vision-030320-062352 -
Physiological Research Dec 2021If the eyes are windows into the soul, then the pupils represent at least the gateway to the brain and can provide a unique insight into the human mind from several... (Review)
Review
If the eyes are windows into the soul, then the pupils represent at least the gateway to the brain and can provide a unique insight into the human mind from several aspects. The changes in the pupil size primarily mediated by different lighting conditions are controlled by the autonomic nervous system regulated predominantly at the subcortical level. Specifically, parasympathetically-linked pupillary constriction is under the Edinger-Westphal nucleus control and sympathetically-mediated pupillary dilation is regulated from the posterior hypothalamic nuclei. However, the changes in the pupil size can be observed at resting state even under constant lighting, these pupillary changes are mediated by global arousal level as well as by various cognitive factors. In this context, autonomic pathways modulating changes in the pupil size in response to the different light levels can be influenced by multiple central descending inputs driving pupillary changes under steady lighting conditions. Moreover, as the pupillary response is involved in emotional (task-evoked pupillary dilation as an index of emotional arousal) and cognitive (task-evoked pupillary dilation as an index of cognitive workload) stimulation, it can be used to detect the impact of mutual subcortical and cortical structures (i.e. overlapping brain structures included in autonomic, emotional and cognitive regulation) on the pupillary innervation system. Thus, complex understanding of the baseline pupil size´ and pupillary dynamics´ mechanisms may provide an important insight into the central nervous system functioning pointing to the pupillometry as a promising tool in the clinical application.
Topics: Arousal; Autonomic Nervous System; Cognition; Emotions; Humans; Pupil
PubMed: 35199551
DOI: 10.33549/physiolres.934749 -
Current Opinion in Neurology Feb 2008To give an overview on topics of pupillary function selected according to their relevance in clinical neurology. Mainly publications of the last 3 years have been...
PURPOSE OF REVIEW
To give an overview on topics of pupillary function selected according to their relevance in clinical neurology. Mainly publications of the last 3 years have been considered.
RECENT FINDINGS
The discovery of photosensitive retinal ganglion cells not serving vision, but serving circadian rhythm and the pupil initiated many studies. There is evidence that pupil reaction to light might be preserved even if all rods and cones are lost. Spontaneous pupillary contractions in darkness occur in sleepy subjects and have been used to quantify the state of alertness. Apraclonidine eye drops have been suggested to diagnose Horner syndrome. Iatrogenic cause and carotid artery dissection are the most frequently reported underlying causes of Horner syndrome. Anti-Hu antibodies may be associated with tonic pupils.
SUMMARY
Pupil studies in blind patients may give new insights into the function of the pupillary system. Testing for sleepiness by means of pupillography might be used more frequently. Testing for Horner syndrome still needs to be done with cocaine eye drops. Clinical evaluation has to be focused on detecting additional signs and symptoms. Unknown malignancy is very rare. In the tonic pupil (Adie syndrome) autoantibodies may play a role, in exceptional cases it might represent a paraneoplastic disorder.
Topics: Adaptation, Ocular; Adrenergic alpha-Agonists; Animals; Clonidine; Humans; Pupil; Pupil Disorders; Reflex, Pupillary; Retina
PubMed: 18180650
DOI: 10.1097/WCO.0b013e3282f39173 -
Perceptual and Motor Skills Dec 2022We investigated pupillary responses to the world's shortest fixed verses, Japanese as aesthetic poetry (AP) and as comic poetry (CP), in comparison with non-poetry...
We investigated pupillary responses to the world's shortest fixed verses, Japanese as aesthetic poetry (AP) and as comic poetry (CP), in comparison with non-poetry control stimuli (NP) comprised of slogans that had the same rhythm patterns. Native Japanese speakers without literary training listened to these stimuli while we recorded their pupil diameters. We found that participants' pupils were significantly dilated for CP compared to NP in an early time window. While AP also evoked larger dilations than NP, the latency for AP-related pupil dilation was relatively long. Thus, lay people experience quick and intense arousal in response to funny and humorous words, while aesthetic properties of words may also elicit intense but slower changes in listeners' arousal levels, presumably because they evoke more implicit and subtle emotional effects. This study is the first to provide evidence that poetic language elicits human pupillary dilation. A better understanding of the cognitive and neural substrates for the sensitive awareness of pleasures expressed via poetic language will provide insights for improving mental and physical health. Hence, pupillometry can act as a useful convenient measurement to delineate the sympathetic activation of emotional contexts via language.
Topics: Humans; Pupil; Emotions; Arousal; Auditory Perception; Language
PubMed: 36151717
DOI: 10.1177/00315125221126778 -
Clinical Autonomic Research : Official... Apr 2009Pupil tests provide a convenient and simple method for evaluation of autonomic function. Most patients with autonomic disorders show evidence of sympathetic or... (Review)
Review
Pupil tests provide a convenient and simple method for evaluation of autonomic function. Most patients with autonomic disorders show evidence of sympathetic or parasympathetic deficits in the pupil, and these can be detected using a combination of clinical signs, pupillometric tests (measuring the responses to light, or an accommodative effort, or a sudden noise) and pharmacological tests (using topically applied drugs both to confirm a deficit and to localize the lesion). Caution is needed in the interpretation of these tests, particularly if the deficits are mixed (i.e. sympathetic and parasympathetic) or bilateral. The pattern of autonomic disturbance in the pupils often correlates poorly with autonomic function elsewhere, but may have diagnostic value in discriminating between different underlying conditions.
Topics: Autonomic Nervous System; Autonomic Nervous System Diseases; Cocaine; Diagnostic Techniques, Neurological; Humans; Pupil; Pupil Disorders; Reflex, Pupillary
PubMed: 19190959
DOI: 10.1007/s10286-009-0515-2 -
Perception Jun 2022When the pupil dilates, the amount of light that falls onto the retina increases. However, in daily life, this does not make the world look brighter. Here we asked...
When the pupil dilates, the amount of light that falls onto the retina increases. However, in daily life, this does not make the world look brighter. Here we asked whether pupil size (resulting from active pupil movement) influences subjective brightness in the absence of indirect cues that, in daily life, support brightness constancy. We measured the subjective brightness of a tester stimulus relative to a referent as a function of pupil size during tester presentation. In Experiment 1, we manipulated pupil size through a secondary working-memory task (larger pupils with higher load and after errors). We found some evidence that the tester was perceived as darker, rather than brighter, when pupils were larger. In Experiment 2, we presented a red or blue display (larger pupils following red displays). We again found that the tester was perceived as darker when pupils were larger. We speculate that the visual system takes pupil size into account when making brightness judgments. Finally, we highlight the challenges associated with manipulating pupil size. In summary, the current study (as well as a recent pharmacological study on the same topic by another team) is intriguing first steps towards understanding the role of pupil size in brightness perception.
Topics: Cues; Humans; Judgment; Memory, Short-Term; Pupil; Visual Perception
PubMed: 35491711
DOI: 10.1177/03010066221094757 -
Current Opinion in Ophthalmology Nov 2013Dilated pupil is a diagnostic challenge encountered by neurologists and ophthalmologists. The aim of this review is to provide an overview of the current data and... (Review)
Review
PURPOSE OF REVIEW
Dilated pupil is a diagnostic challenge encountered by neurologists and ophthalmologists. The aim of this review is to provide an overview of the current data and guidelines concerning dilated pupils.
RECENT FINDINGS
The majority of recent reports on dilated pupils are indicative of several medical conditions that require evaluation. The topical synthetic parasympatholytic agents; local contamination of antihistamines with their antimuscarinic effects; atropine, scopolamine, and tropane alkaloids in all species of Datura plants may produce mydriasis.
SUMMARY
The causes of pupillary dilatation can be unilateral, bilateral, and transient. The clinical approach to dilated pupils requires stepwise evaluation, and based on the findings, unnecessary and costly procedures can be avoided.
Topics: Humans; Mydriasis; Ophthalmic Solutions; Pharmaceutical Preparations; Pupil
PubMed: 24100369
DOI: 10.1097/ICU.0000000000000005 -
Canadian Journal of Experimental... Sep 2022Pupil dilation provides a window into recognition memory processes. During a recognition test, the pupil dilates more in response to a recognized studied item than to a...
Pupil dilation provides a window into recognition memory processes. During a recognition test, the pupil dilates more in response to a recognized studied item than to a correctly rejected new item. Various explanations for this have been offered. By a retrieval effort account, the pupil's response on a recognition test reflects the cognitive effort needed to retrieve items from memory. By a memory strength account, pupil dilation reflects the strength of the subjective memory experience elicited by items at test. To compare these accounts, we varied levels of processing (LOP) at study, then measured pupil dilation on a delayed recognition test during which participants made recollection/familiarity judgements. Pupil dilation at test was similar whether test items had been studied in a deep or shallow LOP task, but was greater when deep, shallow, and new test items were experienced as recollected rather than as familiar. This pattern supports the memory strength account rather than the retrieval effort account of pupil dilation during a recognition test. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Topics: Humans; Judgment; Memory; Mental Recall; Pupil; Recognition, Psychology
PubMed: 35549359
DOI: 10.1037/cep0000283 -
Journal of Experimental Child Psychology Feb 2024In this study, it was investigated whether an emotional response would occur in pupil contagion by using skin conductance response (SCR) in 5- and 6-month-old infants....
In this study, it was investigated whether an emotional response would occur in pupil contagion by using skin conductance response (SCR) in 5- and 6-month-old infants. In the experiment, emotional responses to pupil diameter change (dilating/constricting) between the face and eyes regions were compared by using pupil diameter response and SCR. The results showed that pupil diameter responses to pupil diameter changes did not differ between face and eyes regions. The emotional response indicated by the SCR significantly increased when participants looked at dilating pupils of face stimuli compared with when participants looked at constricted pupils of face stimuli. In addition, we found a significant correlation between SCR and pupil dilation in the face. This means that pupil diameter expansion significantly increases emotional response in pupil dilation of the face region.
Topics: Infant; Humans; Pupil; Emotions; Face
PubMed: 37883903
DOI: 10.1016/j.jecp.2023.105801 -
Journal of Psychiatric Research Feb 2018Individuals suffering from depression often have difficulty trusting others. Previous research has shown a relationship between trust formation and pupil mimicry - the...
Individuals suffering from depression often have difficulty trusting others. Previous research has shown a relationship between trust formation and pupil mimicry - the synchronization of pupil sizes between individuals. The current study therefore examined whether pupil mimicry is weaker in depressed individuals and an underlying factor of their low levels of trust. Forty-two patients with major depressive disorder (MDD) and 40 healthy control subjects played trust games with virtual partners. Images of these partners' eye regions were presented to participants before they had to make a monetary investment decision. Partners' pupils either dilated, constricted, or remained static over the course of 4-s interactions. During the task, participants' pupil sizes were recorded with eye-tracking equipment to assess mimicry. The results confirm that patients with MDD were somewhat less trusting than controls and used another's pupillary cues differently when deciding to trust. Specifically, whereas healthy controls trusted partners with dilating pupils more than partners with constricting pupils, patients with MDD particularly trusted partners whose pupils changed in size less, regardless of whether partners' pupils were dilating or constricting. This difference in investment behavior was unrelated to differences in pupil mimicry, which was equally apparent in both groups and fostered trust to the same extent. Whereas lower levels of trust observed in patients with MDD could not be explained by differences in pupil mimicry, our data show that pupil dilation mimicry might help people to trust. These findings provide further evidence for the important role of pupil size and pupil mimicry in interpersonal trust formation and shed light on the pathophysiology of clinically low trust in patients with MDD.
Topics: Adult; Decision Making; Depressive Disorder, Major; Eye Movement Measurements; Female; Humans; Male; Middle Aged; Pupil; Social Perception; Trust
PubMed: 29202275
DOI: 10.1016/j.jpsychires.2017.11.007