Study On Neural Circuits Related To Feeding Behavior In Insular And Nucleus Accumbens

The regulation of feeding behavior is an extremely complicated process.The feeding behavior of human beings is regulated complicatedly by the loop of the central nervous system.The nervous system produces a series of reactions through the signals triggered by hormones stimulated by the feeding process.Feeding behavior is regulated not only by the body's homeostasis,but also by emotions,memory,rewards,and cognitive systems.The hypothalamus in the feeding center is mainly responsible for homeostasis regulation.In addition,the brain regions involved in reward,such as VTA(Ventral Tegmental Area),NAc(Nucleus Accumbens),brain regions involved inemotion/memory,such as amygdala,hippocampus,etc.,was found that participated inthe regulation of feeding behavior.The insular cortex is an important brain area which accepts,processes,and integrates taste,or a brain area that produces visceral memory.In addition,the insular have a unique function,which is intrinsic to the insular and is perceived and regulated by the insula.The insula is integrated into a unique network that is responsible for the neural control of the appetite and the regulation of energy balance.The anterior insular cortex is highly responsive to different food stimuli as part of the initial taste and initial olfactory cortex.In addition to the taste of the food,the fat content also activates the activity of the taste and reward related brain areas.High-fat foods can promote excessive eating and activate reward pathway in the brain,such as NAc related pathways.This property of high-fat foods has been advantageous in environments where food sources are scarce,but may become a potential hazard in modern society.Previous studies have only found that foods can activate related brain regions such as insular in imaging data such as MRI imaging.However,due to the limitation of imaging resolution,this part of the study could not analyze the specific loop and make quantitative statistics of neurons responding to the loop further.So we used immunohistochemistry and neural circuit tracing to study the activity of feeding behavior in the insular and NAc and found that chocolate and peanut butter which are high-fat food can induce the expression of c-fos in the insular cortex and NAc and the c-fos signals is significantly increased.Next,we used the neural circuit tracing technique to study the neural circuit connection between the insular and NAc,and found that the Camk II neurons in the insular cortex project to the NAc.Then,we use reverse tracking and immunohistochemistry co-localization to reveal that some of the neurons activated by food cues participated in the loop of the insular-NAc.The above findings provide evidence for studies of feeding-related studies in the insular-NAc circuit.In order to study the mechanism of eating disorders and other disorders of nutritional metabolism as well as the treatment and prevention of these diseases to open up new ideas.