Changes in pupil diameter can reflect high-level cognitive signals that depend on central neuromodulatory mechanisms. However, brain mechanisms that adjust pupil size are also exquisitely sensitive to changes in luminance and other events that would be considered a nuisance in cognitive experiments recording pupil size. We implemented a simple auditory experiment involving no changes in visual ...

Mental fatigue is often characterized by reduced motivation for effortful activity and impaired task performance. We used subjective, behavioral (performance), and psychophysiological (P3, pupil diameter) measures during an n-back task to investigate the link between mental fatigue and task disengagement. After 2 h, we manipulated the rewards to examine a possible reengagement effect. Analyses ...

During sustained viewing of an ambiguous stimulus, an individual's perceptual experience will generally switch between the different possible alternatives rather than stay fixed on one interpretation (perceptual rivalry). Here, we measured pupil diameter while subjects viewed different ambiguous visual and auditory stimuli. For all stimuli tested, pupil diameter increased just before the report...

AIMS To investigate the effects of the D2-receptor agonist pramipexole with and without the co-administration of the peripherally acting D2-receptor antagonist domperidone on measures of alertness, autonomic and endocrine function. METHODS Sixteen male volunteers participated in four weekly sessions of pramipexole 0.5 mg, domperidone 40 mg, their combination, and placebo administered accordin...

background : patients with alzheimer's disease (ad) reportedly hibit hypersensitivity to much diluted tropicam solution (0.005%), a m4 muscarinic receptor antagonist. therefore aocular application of 0.005% tropicamide ma be useful for screening dementia. the aim of this study was to simplify the pupil response test by using a new image analyzing system, which consists of a cheap, simple, and e...

To cite: Rajasekharan C, Thomas VA, Gayathry R, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014204619 DESCRIPTION A 50-year-old male manual labourer attended the outpatient department with history and clinical features of upper respiratory infection. He had studied up to the fifth grade. There was no history of visual symptoms. There was no significant...

OBJECTIVE The purpose of this study was to investigate autonomic nervous system dysfunction by measuring pupil sizes in pediatric patients with allergic rhinitis. SUBJECTS AND METHODS The study group consisted of 60 children (28 girls and 32 boys) who were age and gender matched with the control group, which also consisted of 60 children (26 girls and 34 boys). The diagnosis of allergic rhini...

BACKGROUND To compare the efficacy and safety of a new ocular insert versus conventional mydriasis in cataract surgery. METHODS We selected 70 patients undergoing cataract surgery. Thirty five patients (Group 1) received instillation of mydriatic drops (tropicamide 1%, phenylephrine 10%, and cyclopentolate 1%) prior to surgery, and 35 patients (Group 2) had a Mydriasert insert (Théa Pharma) (...

PURPOSE We investigated the relationships between the ocular anterior segment biometry and the ocular high-order aberrations (HOAs) during accommodation by combined ultralong scan depth optical coherence tomography (UL-OCT) and wavefront sensor. METHODS We enrolled 35 right eyes of young healthy subjects (21 women and 14 men; age, 25.6 ± 3.1 years; spherical equivalent refractive error, -0.41...

Non-luminance-mediated changes in pupil diameter have been used since the first studies by Darwin in 1872 as indicators of clinical, cognitive, and arousal states. However, the relation between processes involved in motor control and changes in pupil diameter remains largely unknown. Twenty participants attempted to compensate random walks of a cursor with a computer mouse to restrain its traje...