Cholinergic Modulation Of Neurons In Layers ? ? ? Of Medial Entorhinal Cortex

Medial entorhinal cortex(MEC),which is the media structure of hippocampus and neocortex,plays important roles in spatial navigation,working memory and so on.Neurons of the superficial layer and the deep layer cooperate with each other in order to perform functions.Neurons of the superficial layer mainly outputs to the hippocampus,while neurons of the deep layer receive information from the hippocampus.Neurons in different positions perform different functions.Recent studies have shown that cholinergic projections to MEC are targeted,and cholinergic can regulate some cellular electrophysiological properties of neurons.However,now there is no systematic study on the research "whether the cellular properties of neurons in differential locations of MEC are influenced differently by cholinergic activation".The purpose of this project is to study the passive and active cellular electrophysiological properties of neurons,which is in the second,third or fifth layers of MEC along the dorsal and ventral axis,and the modulation of carbachol on them.The whole cell patch clamp technique was used to collect cell membrane electrical signals by different current stimulation schemes.At the same time,biocytoin was injected into the neurons to reconstruct the morphology,and the cell position was recorded according to the anatomical distribution characteristics.By analysing multiple sets of data of electrical signals,we obtain several supra-threshold and subthreshold electrophysiological parameters.The results showed that the regulation of carbachol on sag ratio of neurons in the second,third or fifth layers of MEC was different.Carbachol can reduce the sag ratio of neurons in the second and third layer.The sag ratio,input resistance,resting membrane potential,and AP amplitude of neurons along the dorsal to ventral axis in the second,third or fifth layers of MEC presented a notable changing trend,which was consistent with the previous research results.The regulatory effect of carbachol on neurons in the fifth layer of MEC is related to its distribution along the dorsal to ventral axis,which is different from neurons in other layers.The sag ratio of MEC cells in the second layer is higher than ones in other layers,which may be due to the fact that there are a large number of stellate cells in the second layer.The input resistance of neurons in the second,third and fifth layers of MEC was not affected by carbachol,but it was related to its position distribution.The input resistance of neurons in the deep layer of MEC was significantly greater than that of neurons in superficial layers.The input resistance of neurons located in the dorsal of the MEC layer 2 was lower than ones in the ventral reguion.However,in the third and fifth layers,the input resistance of ventral neurons was slightly lower than ones in dorsal place.Cholinergic activation can significantly influence some electrophysiological properties of MEC neurons.The innovation of this project is: we systematically studied the characteristics of some cellular properties of MEC neurons in the position of the layer 2,3 or 5 along the dorsal and ventral axis.In conclusion,in this study,we reveal the clear distribution characteristics of some cellular properties along the dorsal to ventral region in each layer,and the regulatory role of cholinergic activation.The research results of this project provide experimental basis and reference for exploring how cholinergic participates in and regulates the special functions of MEC neurons.