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. 2008 Nov 19;28(47):12523–12534. doi: 10.1523/JNEUROSCI.2715-08.2008

Figure 3.

Figure 3.

The single-trial responses of many AOB neurons are sufficient to discriminate FMU from MMU over a range of concentrations. A, Changes in firing rate in response to MMU plotted against the changes in firing rate in response to FMU for 54 urine-responsive (p < 0.01; see Materials and Methods) AOB neurons. AOB neurons display all combinations of increases and decreases in firing rate in response to FMU and MMU, with some tendency to be selective for a single stimulus. Each point represents one cell; error bars indicate SEM. B, Reliability of single neurons' single-trial responses for the discrimination of high-K+ solution from control, averaged across a population of neurons and plotted as a function of time relative to stimulus onset. Cells are grouped according to their overall selectivity for FMU versus MMU (see Materials and Methods). Note that chance detection corresponds to d′ ≥ 0 because d′ takes the scaled absolute value of any differences, even those arising from sampling statistics (see Materials and Methods). C, Time course of discrimination of a neuron's preferred urine stimulus (1:100 FMU or 1:100 MMU, whichever produced the larger positive Δr for that cell) from control; plotting as in B. D, Time course of discrimination of 1:100 FMU from 1:100 MMU; plotting as in B. E, Histogram showing the d′ values for all 65 cells with at least 3 stimulus presentations for both FMU and MMU and a response (p < 0.01) to at least one of the two stimuli. Vertical red lines indicate d′ values of 1 and 2. 41 cells (55%) had a d′ >1 (corresponding to correct single-trial discrimination ∼ 76% of the time, see Materials and Methods), and 23 cells (31%) had a d′ > 2 (92% correct discrimination). F, d′ values for 1:300 diluted stimuli plotted against d′ values for 1:100 diluted stimuli; each point represents one cell. Black line indicates the expected locations if the d′ values at the two concentrations are equal; red line indicates the least squares estimate of the average slope (95% confidence interval given by dashed lines). Of 34 cells tested with at least 3 stimulus presentations at 1:300 diluted, 18 (53%) had a d′ >1, and 5 (15%) had a d′ >2. G, d′ values for stimuli at an unknown concentration (see Materials and Methods) plotted against d′ values for 1:100 diluted stimuli. The estimated slope is not 39 cells, 17 (50%) had d′ values >1, and 5 (15%) had d′ values >2.