FaPDA: Facial paralysis detection algorithm applied in mice

Abstract

Facial paralysis is characterized by an injury to the facial nerve, causing the loss of the functions of the structures that it innervates and changes in the central nervous system in the motor cortex. Therefore, it is important to use experimental models to further the neurophysiological study. Currently, the models have some limitations for the study of facial paralysis. Therefore, the development of an algorithm capable of automatically detecting facial paralysis and overcoming the existing limitations is proposed. C57/BL6 mice were used, which produced irreversible facial paralysis with permanent effects and reversible facial paralysis, where the effects of the paralysis disappear within the first 15 days after the nerve injury. Video recordings were made of the faces of paralyzed mice to develop the algorithm for detecting facial paralysis applied to mice, which allows us to detect the presence of reversible and irreversible facial paralysis automatically. At the same time, the algorithm was used to track facial movement during oral stimulation with sucrose and extracellular electrophysiological recordings in the anterolateral motor cortex. In the basal state, mice can make facial expressions associated with a pleasurable state, and the algorithm detects this movement; at the same time, the movement correlates with the activation in the cortical area. In the presence of facial paralysis, the algorithm can not detect movement. Therefore, it concludes that the condition exists, and the neuronal activity in the cortex is affected with respect to the evolution of facial paralysis. Therefore, the facial paralysis detection algorithm applied to mice allows deduce the presence of experimental facial paralysis, in the presence of oral stimulation or without it, at the same time that cortical electrophysiological recordings can be made for the neurophysiological study of facial paralysis. Significance StatementAutomatic detection of facial paralysis by video recording of the face of mice can help to identify the presence of the condition more easily. It can also used to study facial movement, like facial expressions, and their neural correlates in cortical and subcortical strata. This will allow understanding in depth the level of affectation that facial paralysis can produce at the peripheral and central nervous system levels.