Ectorhinal Cortex Specific Output Circuit Induced Place Preference Behavior

objective The reward system is highly related to many emotional disorders,such as depression,anxiety and autism caused by lack of pleasure,and addiction and obsessive-compulsive disorder caused by excessive pursuit of rewards.Such diseases cause severe disturbance to the daily life of patients and their families.The 2019 Chinese Mental Health Survey(CMHS)showed that in addition to senile dementia,the lifetime weighted prevalence of six types of mental disorders was 16.6%,which means that at least one out of seven residents had at least one mental disorder during their lifetime.Studying the pathogenesis and searching for effective treatment for such mental disorders is urged by the public health and neuroscience research agencies.The medial temporal lobe(MTL)is an important part of the brain and is closely related to learning,memory and emotion regulation.MTL mainly includes hippocampus(HIP),parahippocampal,perirhinal(PRh),entorhinal(ENT),ectorhinal(ECT).Previous researchers have studied functions of hippocampus,entorhinal cortex and other brain regions,which involved in learning,memory,cognition and emotion.ECT and the PRh is narrow and closely connected,therefore Precise studies of ECT's function using modern neurobiological techniques are lacking here.So far,the structure and function of ECT is still unclear.Here we focused on how ECT works in mouse approach or avoidance behavior.Methods Using virus tracing technique,rAAV-CamkII-EGFP was used to inject into ETC to find the output of ECT.We also inject AAV-CamKII-cre,AAV-Ef1a-DIO-hChR2-mCherry or AAV-Ef1a-DIO-mCherry into ECT to specific regulates the neural circuits.Using three-chamber exploring test and real-time place preference test to investigate ECT-mediated preference or aversion behavior Results (?)Using virus tracer technology we found that ECT project to the BLA and NAC.(?)Exploring the function of the ECT-BLA neural circuits.Using threechamber exploring test,we found that the activation of the ECT-BLA projections can decrease the mouse's preference to the unfamiliar chamber.In real-time place preference test,activate ECT-BLA neural circuits can induce place preference.At the same time,activation of ECT-BLA neural circuits had no effect on the movement nor anxiety of the mice.(?)Exploring the function of the ECT-NAC neural circuits.Using threechamber exploring test and real-time place preference test,we found that activation of the ECT-NAC projections did not affect the mouse's performance.At the same time,activation of ECT-NAC circuits had no effect on the movement nor anxiety of the mice.ConclusionActivation of ECT-BLA neural circuits can increase the location preference in 3-chamber exploring test and real-time place preference test in free behaving mice.This is the first time to show that ECT-BLA is associated with preference behavior.