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[퀀텀브레인] canonical cortical microcircuit

by 변정구 posted Feb 17, 2011
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(논문) Excitatory Connections Made by Presynaptic Cortico-Cortical Pyramidal Cells in Layer 6 of the Neocortex


Canonical Cortical Microcircuit
a fundamental processing unit which can be recruited by different cortical or subcortical areas and therefore solve very different tasks.


A Statistical Analysis of Information- Processing Properties of Lamina-Specific Cortical Microcircuit Models



(그림 설명) Cortical microcircuit template. Numbers at arrows denote connection strengths (mean amplitude of PSPs measured at soma in mV) and connection probabilities (in parentheses) according to Thomson and others (2002), for connections between cortical neurons in 3 different layers, each consisting of an excitatory (E) and an inhibitory (I) population, with an estimated maximal horizontal distance of up to 100 um.

Most of the data are from rat cortex, except for interconnections in layer 4 (italic), which are from cat. (Connections from L2/3-I to L5-E are reported in Thomson and others [2002], but are discussed only qualitatively. Hence, the entry for connections from L2/3-I to L5-E [marked by a question mark] is only an extrapolation.

The same applies to connections from L4-I to L2/3-I. No data on the amplitudes of inhibitory PSPs from L5-I to L5-I are given in Thomson and others [2002], hence the corresponding entry is just a guess.) Percentages at input streams denote connection probabilities for input neurons used in our simulations. In addition, each neuron receives background noise reflecting the synaptic inputs from a large number of more distal neurons (see Methods).

Alex thomson, The School of Phamacy, University of London


Synaptic Transmission in the Neocortex


(그림설명) Synaptic transmission in the neocortex: The scheme represents the main neuron types and synaptic connections in the neocortex. Excitatory glutamatergic neurons in red, and inhibitory GABAergic neurons in blue.

Abbreviations:
CHC: chandelier cell,
BC: basket cell,
PC: pyramidal cell,
BP: bipolar cell,
MC: Martinotti cell,
BTC: bitufted cell,
DBC: double-bouquet cell,
NGC: neurogliaform cell,
SSC: spiny-stellate cell,
CRC: Cajal-Retzius cell.

EPSPs : excitatory postsynaptic potentials
EPSCs : excitatory postsynaptic currents
IPSPs : inhibitory postsynaptic potentials

The electrophysiological properties of the different types of synapses are depicted in the inserts. The presynaptic actionpotential train is depicted above the postsynaptic response (except in fig. 3g, where only postsynaptic traces are shown).

a. reciprocal depressing connection between PC and BP
b. depressing inhibitory connection between BC and PC
c. facilitating excitatory connection between PC and MC
d. depressing excitatory connection between L5 PCs
e. depressing excitatory connection between L6 PCs
f. depressing excitatory connection between L6 PC and L5 PC
g. depressing and facilitating excitatory connections between PC and NBC
h.depressing excitatory connection between L4 PCs