Examples of intracellular activities: membrane potential slow oscillations (MPSOs) and respiration-related discharge patterns.

<p><i>A) Typical recordings of intracellular signals</i>. Cell numbers were extracted from the matrix presented in panel B of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0043964#pone-0043964-g002" target="_blank">Figure 2</a>. Top: intracellular recording; bottom: respiratory signal with expiration (Expi) and inspiration (Inspi) separated by a dotted line. The gray circles mark the inspiration/expiration transitions. The horizontal black line at the top of the intracellular signal indicates odor stimulation. The action potentials were truncated to improve the visibility of the membrane potential. The intracellular recordings were obtained without a stabilizing current in 1 and 3 and with a −0.15 nA stabilizing current in 2. <i>B) Respiration-triggered membrane potential averages before (Control) and during odor stimulation (Odor) of the cells presented in A.</i> 1) A cell without membrane potential slow oscillation (NoMPSO) prior to odor stimulation acquired a positive membrane potential slow oscillation (MPSO+) during odor stimulation. 2) and 3) Cells without MPSO before odor stimulation that exhibited negative membrane potential slow oscillation (MPSO-) during odor stimulation. A vertical dotted line indicates the transition between inspiration and expiration, and a horizontal dotted line represents the mean membrane potential. The up-point proportion is indicated for each averaged MPSO in the right corner. <i>C) Respiration-triggered histograms of the action potentials from the cells presented in panel A before (Control) and during odor stimulation (Odor).</i> 1) A cell without an action potential (null pattern) prior to odor stimulation exhibited an excitatory-simple-synchronized pattern (S+) during odor stimulation. 2) A cell exhibiting a non-synchronized discharge pattern (NoS) in the control condition acquired a suppressive-simple-synchronized discharge pattern (S-) during odor stimulation. 3) A cell with a null pattern during the control period manifested a complex synchronized discharge pattern (Sc) during the odor period. The vertical dotted line indicates the inspiration/expiration transition.