Searching for Complexity in the Human Pupillary Light Reflex

• Autor(a) principal: Laureano, Rosário
• Data de Publicação: 2020
• Outros Autores: Mendes, Diana, Grácio, Clara, Laureano, Fátima
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10174/34507; https://doi.org/Laureano, R.D.; Mendes, D.; Grácio, C.; Laureano, F. Searching for Complexity in the Human Pupillary Light Reflex. Mathematics 2020, 8, 394. https://doi.org/10.3390/math8030394; https://doi.org/doi.org/10.3390/math8030394
• topic: pupil; delay differential equations; dynamic stability; Andronov–Hopf bifurcation

This article aims to examine the dynamical characteristics of the pupillary light reflex and to provide a contribution towards their explanation based on the nonlinear theory of dynamical systems. To introduce the necessary concepts, terminology, and relevant features of the pupillary light reflex and its associated delay, we start with an overview of the human eye anatomy and physiology with emphasis on the iris, pupil, and retina. We also present the most highly regarded models for pupil dynamics found in the current scientific literature. Then we consider the model developed by Longtin and Milton, which models the human pupillary light reflex, defined by a nonlinear differential equation with delay, and present our study carried out on the qualitative and quantitative dynamic behavior of that neurophysiological control system.