The pupil mechanism in the acone apposition eye of the semi-aquatic common backswimmer Notonecta glauca (Hemiptera) was investigated with infrared reflectometry of the pseudopupil. This method allows non-invasive continuous measurements of pupil responses in the living animal. The dynamic range of the pupil sensitivity is about 7 log units during daytime and 6 log units at night. During the day...

A number of studies have shown that pupil size increases transiently during effortful decisions. These decision-related changes in pupil size are mediated by central neuromodulatory systems, which also influence the internal state of brain regions engaged in decision making. It has been proposed that pupil-linked neuromodulatory systems are activated by the termination of decision processes, an...

A thin slit-lamp beam illuminating the pupil margin produces clearly visible pupil oscillations. These oscillations can be timed with a stopwatch, thus producing a measurement of the 'edge-light pupil cycle time'. The pupil cycle time is remarkably stable in various testing situations and is repeatable within about ±3% over extended periods of time. Expected normal distribution and 95 % confide...

In this paper a low cost pupil center locating system was introduced and a robust pupil center estimation method was presented. Differing from other methods, eye image was converted into the space of chi-square significance of measurement residual (CSMR) first in the proposed method. In CSMR space, pupil area was enhanced while others were depressed. And then, a threshold selected by the statis...

In the present work we analyzed the pupil size behavior of 40 subjects while they read well-defined sentences with different contextual predictability (i.e., regular sentences and proverbs). In general, pupil size increased when reading regular sentences, but when readers realized that they were reading proverbs their pupils strongly increase until finishing proverbs' reading. Our results sugge...

Pupil size is correlated with a wide variety of important cognitive variables and is increasingly being used by cognitive scientists. Pupil data can be recorded inexpensively and non-invasively by many commonly used video-based eye-tracking cameras. Despite the relative ease of data collection and increasing prevalence of pupil data in the cognitive literature, researchers often underestimate t...

Association of migraine and tonic pupil has been reported very rarely. We reported a young female with symptoms of migraine who developed a mydriatic pupil in one of her attacks. The pupil was unresponsive to light with little response to near reflex. In 0.125% pilocarpine test affected pupil responded significantly and tonic pupil was diagnosed. The patient's problem became severe after a one-...

Complex natural environments favor the dynamic alignment of neural processing between goal-relevant stimuli and conflicting but biologically salient stimuli like social competitors or predators. The biological mechanisms that regulate dynamic changes in vigilance have not been fully elucidated. Arousal systems that ready the body to respond adaptively to threat may contribute to dynamic regulat...

The orienting reflex is initiated by a salient stimulus and facilitates quick, appropriate action. It involves a rapid shift of the eyes, head, and attention and other physiological responses such as changes in heart rate and transient pupil dilation. The SC is a critical structure in the midbrain that selects incoming stimuli based on saliency and relevance to coordinate orienting behaviors, p...

Purpose: Pupil perimetry has so far been performed by the two following methods: suprathreshold perimetry during which the amplitude or ratio of pupil constriction is determined, and threshold perimetry during which the threshold of pupil reaction is determined. The authors compared the values obtained with these two methods using the modified Octopus 1-2-3. Subjects and methods: Pupil perimetr...