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Diversity in the structure of action potential‐mediated neural connectivity within rat supra chiasmatic nucleus
Author(s) -
Min Cheolhong,
Kim Hyun,
Choi Wonshik,
Lee Kyoung J.
Publication year - 2019
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14417
Subject(s) - inhibitory postsynaptic potential , neuroscience , receptive field , optogenetics , postsynaptic current , postsynaptic potential , gabaergic , biology , excitatory postsynaptic potential , suprachiasmatic nucleus , physics , biophysics , central nervous system , receptor , genetics
Action potential (AP)‐mediated cell‐to‐cell communication is essential for the frequency‐locking and phase‐synchronization of the clock cells within the biological master clock, suprachiasmatic nucleus (SCN). Nevertheless, the morphology of its network connectivity is largely unexplored. Here, with an optimized optogenetic light‐stimulation and scanning protocol, we report some key characteristics of the inhibitory receptive field ( IRF ), the area which brings inhibitory synaptic currents to a given target cell, and basic statistics of the inhibitory network connections of rat SCN clock cells. ChR2 transfected, slice cultures of rat SCN were stimulated by a blue power LED light in a repetitive box‐scanning modes, while a target cell was whole‐cell patched. The registered inhibitory postsynaptic currents, which were brought by light‐induced APs of presynaptic neurons, were mostly GABA ergic. The sizes and shapes of IRF s of SCN cells were very diverse, and the number of presynaptic cells making up the IRF of a given target cell followed an exponential distribution with an average value of 8.9 approximately, according to our clustering analysis which is based on a hybrid measure D , combining the physical distance r and the difference in the current amplitudes of two different sites. Although this estimate inevitably depends on the construct of the measure D , it is found not so sensitive on the parameter w, which weighs the relative significance of the current amplitude different with respect to the physical distance r: The average number of presynaptic neurons varies < 26% over a significant range of 0 < w < 30. On average, the presynaptic connection number density around a target cell falls off as an exponentially decreasing function of r. But, its space constant (~210.7 μm) is quite large that long‐range (>210.7 μm) neural connections are abundant (>66.9%) within the SCN .