The effects of constrained left versus right monocular viewing on the autonomic nervous system

Asymmetrical activation of right and left hemispheres differentially influences the autonomic nervous system. Additionally, each hemisphere primarily receives retinocollicular projections from the contralateral eye. To learn if asymmetrical hemispheric activation induced by monocular viewing would influence relative pupillary size and respiratory hippus variability (RHV), a measure of parasympathetic activity, healthy participants had their left, right or neither eye patched. Pupillary sizes were then recorded with infrared pupillography. Pupillary dilation was significantly greater with left than right eye viewing. RHV, however, was not different between eye viewing conditions. These differences in pupil dilatation may have been caused by relatively greater activation of the right hemispheric-mediated sympathetic activity induced by left monocular viewing or relatively greater deactivation of the left hemispheric-mediated parasympathetic activity induced by right eye patching. The absence of an asymmetry in RHV, however, suggests that hemispheric asymmetry of sympathetic activation was primarily responsible for this ocular asymmetry of pupil dilation

Zjištění závislosti mezi srdeční variabilitou a změnou průměru zornice

The diploma thesis is dedicated to measurement of the pupil size together with cardiac activity and to finding of the relationship between these two signals. There is hypothesis which expects strong relation between these signals as both are innervated by sympathetic and parasympathetic nervous system. In the biofeedback experiment based on eye-tracking is the luminance value of stimulus directed by real time pupil size and the pupil oscillations are generated. The ECG signal is monitored during the experiment. For data analysis was designed an application in Matlab. The application presents pupil and ECG data in time and frequency domain. The pupil oscillation variability and heart rate variability are computed for processing in time-frequency domain. The analysis is mainly in frequency domain and using statistical analyses are obtained values to compare with the theoretical heart rate values.Diplomová práce se zaměřuje na měření velikosti zornic společně s měřením srdeční aktivity a na hledání vzájemného vztahu mezi těmito dvěma signály. Existuje hypotéza, která předpokládá silný vztah mezi těmito signály, jelikož jsou oba inervovány sympatickým a parasympatickým nervovým systémem. Během zpětnovazebního experimentu, založeného na eye-trackingu, se jas promítaného stimulu mění v závislosti na aktuální velikosti zornice a vznikají oscilace zornic. EKG signál je snímán po celou dobu tohoto experimentu. Pro analýzu dat je navržena aplikace v programu Matlab. Oscilace zornic a EKG signál jsou vyobrazeny v časové i frekvenční doméně. Zobrazení v časově-frekvenční doméně je zprostředkováno vykreslením srdeční variability a variability velikosti zornic. Analýza naměřených oscilací poskytla hodnoty pro porovnání s teoretickými znalostmi o srdeční variabilitě.450 - Katedra kybernetiky a biomedicínského inženýrstvívelmi dobř

Infrared Camera-Based Non-contact Measurement of Brain Activity From Pupillary Rhythms

Pupillary responses are associated with affective processing, cognitive function, perception, memory, attention, and other brain activities involving neural pathways. The present study aimed to develop a noncontact system to measure brain activity based on pupillary rhythms using an infra-red web camera. Electroencephalogram (EEG) signals and pupil imaging of 70 undergraduate volunteers (35 female, 35 male) were measured in response to sound stimuli designed to evoke arousal, relaxation, happiness, sadness, or neutral responses. This study successfully developed a real-time system that could detect an EEG spectral index (relative power: low beta in FP1; mid beta in FP1; SMR in FP1; beta in F3; high beta in F8; gamma P4; mu in C4) from pupillary rhythms using the synchronization phenomenon in harmonic frequency (1/100 f) between the pupil and brain oscillations. This method was effective in measuring and evaluating brain activity using a simple, low-cost, noncontact system, and may be an alternative to previous methods used to evaluate brain activity

Standards in Pupillography

The number of research groups studying the pupil is increasing, as is the number of publications. Consequently, new standards in pupillography are needed to formalize the methodology including recording conditions, stimulus characteristics, as well as suitable parameters of evaluation. Since the description of intrinsically photosensitive retinal ganglion cells (ipRGCs) there has been an increased interest and broader application of pupillography in ophthalmology as well as other fields including psychology and chronobiology. Color pupillography plays an important role not only in research but also in clinical observational and therapy studies like gene therapy of hereditary retinal degenerations and psychopathology. Stimuli can vary in size, brightness, duration, and wavelength. Stimulus paradigms determine whether rhodopsin-driven rod responses, opsin-driven cone responses, or melanopsin-driven ipRGC responses are primarily elicited. Background illumination, adaptation state, and instruction for the participants will furthermore influence the results. This standard recommends a minimum set of variables to be used for pupillography and specified in the publication methodologies. Initiated at the 32nd International Pupil Colloquium 2017 in Morges, Switzerland, the aim of this manuscript is to outline standards in pupillography based on current knowledge and experience of pupil experts in order to achieve greater comparability of pupillographic studies. Such standards will particularly facilitate the proper application of pupillography by researchers new to the field. First we describe general standards, followed by specific suggestions concerning the demands of different targets of pupil research: the afferent and efferent reflex arc, pharmacology, psychology, sleepiness-related research and animal studies

A Review of Psychophysiological Measures to Assess Cognitive States in Real-World Driving

As driving functions become increasingly automated, motorists run the risk of becoming cognitively removed from the driving process. Psychophysiological measures may provide added value not captured through behavioral or self-report measures alone. This paper provides a selective review of the psychophysiological measures that can be utilized to assess cognitive states in real-world driving environments. First, the importance of psychophysiological measures within the context of traffic safety is discussed. Next, the most commonly used physiology-based indices of cognitive states are considered as potential candidates relevant for driving research. These include: electroencephalography and event-related potentials, optical imaging, heart rate and heart rate variability, blood pressure, skin conductance, electromyography, thermal imaging, and pupillometry. For each of these measures, an overview is provided, followed by a discussion of the methods for measuring it in a driving context. Drawing from recent empirical driving and psychophysiology research, the relative strengths and limitations of each measure are discussed to highlight each measures' unique value. Challenges and recommendations for valid and reliable quantification from lab to (less predictable) real-world driving settings are considered. Finally, we discuss measures that may be better candidates for a near real-time assessment of motorists' cognitive states that can be utilized in applied settings outside the lab. This review synthesizes the literature on in-vehicle psychophysiological measures to advance the development of effective human-machine driving interfaces and driver support systems

Pupilometria dinâmica e reação à pilocarpina em pacientes com Doença de Chagas

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Pós-graduação em Medicina Tropical, 2016.Introdução: Investigou-se possível desenervação parassimpática ocular na doença de Chagas crônica. Sabe-se que muitas manifestações da doença de Chagas são por danos ao sistema nervoso parassimpático cardíaco e mioentérico. Considerando que a inervação efetora pupilar é feita pelo sistema nervoso simpático e parassimpático e que a pressão intraocular é em parte influenciada por eles, realizaram-se medidas pupilares e da pressão intraocular para investigar danos ao sistema colinérgico ocular em pacientes com doença de Chagas. Métodos: Foram constituídos 02 grupos, sendo um grupo com 80 pacientes chagásicos e um grupo comparativo com 76 participantes saudáveis. Realizou-se pupilometria, teste de hipersensibilidade a pilocarpina 0,125% e medida da pressão intraocular (PIO). Mediu-se o diâmetro basal da pupila (DBP), a amplitude de constrição pupilar absoluta (ACA) e relativa (ACR) e o diâmetro pupilar após pilocarpina 0,125%. Pesquisou-se anisocoria e analisou-se a associação dos parâmetros com o tempo de diagnóstico e com a realização ou não do tratamento específico. Resultados: A prevalência de anisocoria foi significativamente (p < 0,01) maior em pacientes chagásicos do que em não chagásicos. Não houve associação entre as medidas pupilares e o tempo de diagnóstico ou realização de tratamento específico. Os pacientes chagásicos apresentaram valor médio do DBP (p < 0,01), valor médio do diâmetro fotópico (p = 0,02) e valor médio da ACA (p < 0,01) significativamente menores do que os não chagásicos. A ACR não difere significativamente nos chagásicos dos não chagásicos (p = 0,39). A hipersensibilidade ocorreu em 10% dos chagásicos no olho direito e em 2,5% no olho esquerdo. O valor médio da PIO teve significância marginal (p = 0,06) entre os pacientes chagásicos e o grupo comparativo. Conclusão: Os dados sugerem que a análise pupilométrica e o teste de sensibilidade à pilocarpina podem ser um marcador para distinguir os pacientes com doença de Chagas com disfunção colinérgica. Tais medidas indicam que danos parassimpáticos em pacientes com doença de Chagas podem ocorrer no coração, no intestino, mas também no olho.Introduction: We investigated possible ocular parasympathetic denervation in chronic Chagas disease. It is known that many Chagas' disease manifestations are due to damage to heart and myenteric parasympathetic nervous system. Whereas the efferent innervation of the pupil is made by sympathetic and parasympathetic, the nervous system and intraocular pressure is largely influenced by this system, we performed pupillary and intraocular pressure measurements to check possible damage to the ocular cholinergic system in Chagas' disease. Methods: We formed 02 groups, one group of 80 patients with Chagas disease and 01 comparison group of 76 healthy participants. Thus, we performed pupillometry, proceeded the hypersensitivity test to pilocarpine 0.125% and measurement of intraocular pressure (IOP) in individuals with and without Chagas' disease. We measured the scotopic pupil diameter (BPD), the absolute (ACA) and relative (ACR) pupillary constriction amplitude, pupil diameter after pilocarpine 0.125% and IOP. We searched for anisocoria and analyzed the association of the parameters with time from diagnosis and the realization or not of specific treatment. Results: The prevalence of anisocoria was significantly (p < 0.01) higher in patients with Chagas' disease than in non-chagasic. There was no association between pupillary measures and disease time from diagnose or anti-trypanosoma treatment duration. Chagasic patients had mean value of BPD (p < 0.01), mean value of photopic diameter (p = 0.02) and ACA mean value (p < 0.01) significantly lower than the non-chagasic individuals. The ACR does not differ significantly from chagasic to non-Chagas (p = 0,39). Hypersensitivity occurred in 10% of Chagas disease in the right eye and 2.5% in the left eye. The mean IOP had marginal significance (p = 0,06) between patients with Chagas disease and the comparative group. Conclusion: pupillometric analysis and pilocarpine hypersensitivity test may be a marker for distinguishing chagasic patients with cholinergic dysfunction. Such measurements indicate that parasympathetic damage in patients with Chagas' disease can occur not only in the heart, in the intestine and peripheral nervous system, but also in the eye