Differing from other subtypes of inhibitory interneuron,chandelier or axo-axonic cells form depolarizing GABAergic synapses exclusively onto the axon initial segment(AIS)of targeted pyramidal cells(PCs).However,the de...Differing from other subtypes of inhibitory interneuron,chandelier or axo-axonic cells form depolarizing GABAergic synapses exclusively onto the axon initial segment(AIS)of targeted pyramidal cells(PCs).However,the debate whether these AIS-GABAergic inputs produce excitation or inhibition in neuronal processing is not resolved.Using realistic NEURON modeling and electrophysiological recording of cortical layer-5 PCs,we quantitatively demonstrate that the onset-timing of AIS-GABAergic input,relative to dendritic excitatory glutamatergic inputs,determines its bi-directional regulation of the efficacy of synaptic integration and spike generation in a PC.More specifically,AIS-GABAergic inputs promote the boosting effect of voltage-activated Na+channels on summed synaptic excitation when they precede glutamatergic inputs by>15 ms,while for nearly concurrent excitatory inputs,they primarily produce a shunting inhibition at the AIS.Thus,our findings offer an integrative mechanism by which AIS-targeting interneurons exert sophisticated regulation of the input-output function in targeted PCs.展开更多
The axon initial segment(AIS)is a highly specialized axonal compartment where the action potential is initiated.The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons(PyNs),wh...The axon initial segment(AIS)is a highly specialized axonal compartment where the action potential is initiated.The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons(PyNs),which likely contributes to their unique spiking properties.However,whether the various characteristics of AISs can be linked to specific PyN subtypes remains unknown.Here,we report that in the prelimbic cortex(PL)of the mouse,two types of PyNs with axon projections either to the contralateral PL or to the ipsilateral basal lateral amygdala,possess distinct AIS properties reflected by morphology,ion channel expression,action potential initiation,and axo-axonic synaptic inputs from chandelier cells.Furthermore,projection-specific AIS diversity is more prominent in the superficial layer than in the deep layer.Thus,our study reveals the cortical layer-and axon projection-specific heterogeneity of PyN AISs,which may endow the spiking of various PyN types with exquisite modulation.展开更多
A numerical parameter mathematically derived from the graph structure is a topological index.The topological index is the first actual choice in QSAR research and these indices are used to build the correlation model ...A numerical parameter mathematically derived from the graph structure is a topological index.The topological index is the first actual choice in QSAR research and these indices are used to build the correlation model between the chemical structures of various chemicals compounds.Here,we investigate some old degree-based topological indices like Randic index,sum connectivity index,ABC index,GA index,1st and 2nd Zagreb indices,modified second Zagreb index,redefined version of 1st,2nd and 3rd Zagreb indices,hyper and augmented Zagreb indices,forgotten index and symmetric division degree index,and some new degree-based indices like SK index,SK1 index,SK2 index,and AG1 index of triangular chandelier-lattice(TCL).The results are generalized by using edge partition and closed formulas for topological indices of triangular chandelier-lattice are analysed.展开更多
基金supported by the National Natural Science Foundation of China(32130043 and 32071025)the Interdisciplinary Research Fund of Beijing Normal University,China.
文摘Differing from other subtypes of inhibitory interneuron,chandelier or axo-axonic cells form depolarizing GABAergic synapses exclusively onto the axon initial segment(AIS)of targeted pyramidal cells(PCs).However,the debate whether these AIS-GABAergic inputs produce excitation or inhibition in neuronal processing is not resolved.Using realistic NEURON modeling and electrophysiological recording of cortical layer-5 PCs,we quantitatively demonstrate that the onset-timing of AIS-GABAergic input,relative to dendritic excitatory glutamatergic inputs,determines its bi-directional regulation of the efficacy of synaptic integration and spike generation in a PC.More specifically,AIS-GABAergic inputs promote the boosting effect of voltage-activated Na+channels on summed synaptic excitation when they precede glutamatergic inputs by>15 ms,while for nearly concurrent excitatory inputs,they primarily produce a shunting inhibition at the AIS.Thus,our findings offer an integrative mechanism by which AIS-targeting interneurons exert sophisticated regulation of the input-output function in targeted PCs.
基金supported by the National Natural Science Foundation of China(82071450,31972903,and 32000681)Shanghai Pujiang Program(20PJ1401000)+3 种基金the Natural Science Foundation of Shanghai(20ZR1405700)Shanghai Municipal Science and Technology Major Project(No.2018SHZDZX01)ZJ Lab,the Shanghai Center for Brain Science and Brain-Inspired Technologythe Fudan Undergraduate Research Opportunities Program(Wangdao 20046).
文摘The axon initial segment(AIS)is a highly specialized axonal compartment where the action potential is initiated.The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons(PyNs),which likely contributes to their unique spiking properties.However,whether the various characteristics of AISs can be linked to specific PyN subtypes remains unknown.Here,we report that in the prelimbic cortex(PL)of the mouse,two types of PyNs with axon projections either to the contralateral PL or to the ipsilateral basal lateral amygdala,possess distinct AIS properties reflected by morphology,ion channel expression,action potential initiation,and axo-axonic synaptic inputs from chandelier cells.Furthermore,projection-specific AIS diversity is more prominent in the superficial layer than in the deep layer.Thus,our study reveals the cortical layer-and axon projection-specific heterogeneity of PyN AISs,which may endow the spiking of various PyN types with exquisite modulation.
文摘A numerical parameter mathematically derived from the graph structure is a topological index.The topological index is the first actual choice in QSAR research and these indices are used to build the correlation model between the chemical structures of various chemicals compounds.Here,we investigate some old degree-based topological indices like Randic index,sum connectivity index,ABC index,GA index,1st and 2nd Zagreb indices,modified second Zagreb index,redefined version of 1st,2nd and 3rd Zagreb indices,hyper and augmented Zagreb indices,forgotten index and symmetric division degree index,and some new degree-based indices like SK index,SK1 index,SK2 index,and AG1 index of triangular chandelier-lattice(TCL).The results are generalized by using edge partition and closed formulas for topological indices of triangular chandelier-lattice are analysed.
基金supported by the National Natural Science Foundation of China(No.31972903)the Science and Technology Commission of Shanghai Municipality(No.18JC1420302)+1 种基金the Shanghai Pujiang Program(No.20PJ1401000)the Innovative Research Team of High-level Local Universities in Shanghai。
