Kang, Kitano, and Fukai present us with a computational model of cortical neurons that have recently been reported (as a result of in vitro and in vivo experiments, conducted as early as 1999) to show spontaneous transitions between two sub-threshold levels of their membrane potentials, the so-called “up” and “down” states. It is likely that these transitions constitute an elementary process within the cortical computations.

In the paper, the authors “investigate whether the spontaneous bi-stable state transitions can be self-organized in a network of excitatory and inhibitory neurons in the case that the H-current (hyperpolarization-activated cation current) is abundant in excitory neurons.” This is a continuation of a previous study, by some of the authors of this paper, on spike-timing-dependent plasticity (STDP) self-organization phenomena in Hodgkin-Huxley neurons. Since this is a work in progress presentation, a couple of open questions are posed for those interested in furthering the research. Further study is needed to improve the model, which heavily depends on the STDP to account for some of the complex dynamic phenomena of the ionic currents. More realistic neural models also need to be investigated, and compared to the reported biological phenomena.

“In conclusion, the present computational study has revealed that the STDP may lead to self-organization of the spontaneous ‘up’ and ‘down’ transitions, such as observed in cortical neurons, and the spontaneous ‘up’ and ‘down’ transitions are generated by the cooperation of reverberating excitation and the intrinsic property of single neurons.”