FIG. 7.

Across-neuron correlations between stimuli, including the concentration series, depicted in multidimensional scaling plots. The different panels calculated across-neuron correlations using different populations of neurons. A: all neurons; B: all except the B-best cells. C: all neurons except the AN cells (bottom). Differences in concentration are illustrated by the size of the circle (small, lower than the test concentration; middle, test concentration; large, higher than the test concentration). Stimulus qualities are represented by different colors (pink, sweet; purple, umami; yellow, salt; orange, sour; blue, bitter; light blue, QUI). Note that similar qualities cluster together when all cells are included in the analysis (top). QUI is represented as more similar to acids than bitters. When the B-best units are removed (middle), the bitter stimuli spread apart more. When the AN units are removed (bottom), the bitters including QUI, form a more cohesive group. Stimulus abbreviations as in Fig. 2.