Biophoton Radiation And Characteristics Of Rat Motor Cortex Induced By Olfactory Stimulation

Background : Olfaction is the oldest sense in the evolution of species.It is important for foraging activity,individual communication and emotional activities,and affects the development of individual and germline.The nervous system has specialized structures and processing mechanisms to integrate such sensory informations to form coherent perceptual representations and drive adaptive behavior.Many studies have shown that the olfactory system is an ideal model for studying sensory circuits and related decision-making.However,the research on the processing mechanism of olfactory system is not enough,and the description of sensory information integration is only at the beginning.In the process of information transmission in multi-synaptic and long-range neural circuits,the traditional bioelectricial and chemical transmission have not been able to construct a reasonable concept to explain the higher cognitive functions and rapid response to external sensory information.Many studies have demonstrated that biophoton can communicate between cells,and recent experimental evidence and theoretical speculation suggest that biophoton may play a potential role in neural signaling and processing.Therefore,from a new perspective,it is of great significance to explore the internal mechanism of biophoton and olfactory encoding.Research Methods: Based on the ultra-weak biophoton imaging system developed by our research group,we designed and constructed an in vivo biophoton imaging detection system based on optical fiber transmission,which is completely different from the in vitro detection system.We used this detection system to detect biophoton radiation activity in the motor cortex of female and male rats induced by three different odors in order to explore the neural activity significance of biophoton in the complex neural circuits integrating olfactory perception and sensorimotor.Results and Discussion: the results showed that:(1)Three sources of preferred odors(vanillin,predator odors and heterosexual urine)could induce the fluctuation of the biophoton emission in the motor cortex of male and female rats,which may be related to the temporal and spatial patterns of different brain activities caused by the activation of olfactory and olfactory reflex circuits due to the each specific odor difference,and indicates that biophoton may have neural coding significance;(2)Vanillin induced a significant decrease in biophoton activities in the motor cortex of both male and female rats,which may be related to the fact that vanillin enhanced the rats’ comfort and reduced their anxiety behaviors;(3)Predator odor exposure induced a significant increase in biophoton radiation activities in the motor cortex of female rats,which may be related to the characteristic pattern of rodent panic response and activation of neural circuits stimulated by predator odor.However,the biophoton activities in male rats increased briefly,then decreased and returned to normal level,which may reflect the behavioral adaptation of male rats to predators;(4)the heterosexual urine had strong congenital preference and attraction to the rats,which can cause the decrease of the biophoton activities in the motor cortex of the opposite sex rats,suggesting that the odor of the opposite sex could inhibit the activity of the congenitally conserved neural circuits,reflecting the comfort behavior of the animals;(5)Biophoton emission in the motor cortex of male rats was lower than that of female rats under any odor stimulations in this study.We speculated that this might be related to the organism differences between male and female rats and other factors.The specific reasons remain to be further clarified.These findings suggest that biophoton may be involved in the functional activities of olfactory perception and motor regulation of neural circuits in rats,which is instructive for the establishment of biophoton neural coding model and provides new ideas for further understanding of higher brain functions and the internal mechanisms of human mental diseases.