Figure 6: Evaluating combinatorial versus temporal properties of neural activity.

(a) Simulated neural activities in a well-constrained computational model with 100 neurons are shown for a single odourant that activated the same set of neurons but with different temporal structures (left versus right panel). The fraction of neurons reaching their peak values at any given time period is shown below each image plot. (b) Similar plots as in a but now showing responses to a different simulated odourant. Note that the two odourants shown in a and b activate different but partially overlapping subsets of neurons. (c) The more synchronous the ensemble activity, the greater was the overall response as measured by the mean PSTH (±s.e.m.). Asterisks indicate significant difference in spike counts across neurons (*P<0.05, Wilcoxon signed-rank test, n=100). (d) A linear dimensionality reduction analysis of the simulated neural data revealed that odourants that activated the same set of neurons traced response trajectories that were aligned with each other irrespective of their differences in temporal structure.