Figure 12.

Mitral cell population activity in the chip in response to the presentation of four different odors. This activity constitutes the final output of the system in its present configuration. Spiking patterns from 24 of the 48 mitral cells on the chip are depicted. Odorant concentration [C] was modulated as depicted at the bottom of the figure. Compared to the primary representation of the chemical environment by the broadly tuned, concentration-sensitive population of simulated sensors driving the chip, this secondary representation is more sharply tuned, normalized, and exhibits an increased signal-to-noise ratio. For final odor identification and discrimination, this output activity can be sent to a standard pattern recognition engine, or to biomimetic circuits representing higher processing stages in olfactory pathways.