An analysis of the transitions between down and up states of the cortical slow oscillation under urethane anaesthesia

作者：Wilson Marcus T^*; Barry Melissa; Reynolds John N J; Crump William P; Steyn Ross D Alistair; Steyn Ross Moira L; Sleigh James W

来源：Journal of Biological Physics, 2010, 36(3): 245-259.

DOI：10.1007/s10867-009-9180-x

• Cortex
• Neurons
• Slow wave sleep
• Phase transition

We study the dynamics of the transition between the low- and high-firing states of the cortical slow oscillation by using intracellular recordings of the membrane potential from cortical neurons of rats. We investigate the evidence for a bistability in assemblies of cortical neurons playing a major role in the maintenance of this oscillation. We show that the trajectory of a typical transition takes an approximately exponential form, equivalent to the response of a resistor-capacitor circuit to a step-change in input. The time constant for the transition is negatively correlated with the membrane potential of the low-firing state, and values are broadly equivalent to neural time constants measured elsewhere. Overall, the results do not strongly support the hypothesis of a bistability in cortical neurons; rather, they suggest the cortical manifestation of the oscillation is a result of a step-change in input to the cortical neurons. Since there is evidence from previous work that a phase transition exists, we speculate that the step-change may be a result of a bistability within other brain areas, such as the thalamus, or a bistability among only a small subset of cortical neurons, or as a result of more complicated brain dynamics.

• 出版日期2010-6