Article Figures & Data
Figures
- Figure 1.
Behavioral task. A , Experimental setup. A head-fixed mouse is positioned in front of the odor port and a water spout with its front paws resting on a treadmill. An implanted sniffing cannula is connected to the pressure transducer (P) to measure the sniffing signal. The mouse is trained to move the treadmill to the left/right in response to the low/high odor concentration stimulus. The odor stimulus is created by combining three parallel gas lines: an air carrier line (800 ml/min) and two nitrogen lines controlled by mass flow controllers (MFCs) (Alicat Scientific) that go through an odor vial (yellow) and a blank vial. For the high concentration stimulus, the odor vial MFC was set to a flow rate of 80 ml/min and the blank vial MFC was set to a flow rate of 20 ml/min. For the low concentration stimulus, the flow rates were 2 ml/min and 98 ml/min, respectively. The final valve (FV) (4-way Teflon valve; NResearch) switches the odor line and a blank air line (900 ml/min) between the odor port and the exhaust. B , Top, Photoionization detector (PID) (Aurora Scientific) measurement of the time course of the concentration at the odor port for the high and low concentration stimulus (gray lines are individual trials and the blue line is the mean). At 40 ms after the onset of the final valve, the odor concentration reaches 90% of its saturated value. Second panel, Time course of the FV opening. Third panel, Pressure measurement of the sniffing signal (example trace). Note that positive pressure is downward. Green/gray area is the inhalation/exhalation interval. Bottom, Limb velocity (example trace). Positive/negative values indicate rightward/leftward motion. The response time is the interval from inhalation onset to movement onset. The delay from movement onset to FV offset was 110 ± 30 ms (mean ± mean absolute deviation). The intertrial interval was 7 s. C , Example distribution of response times for one mouse for correct trials (blue) and incorrect trials (green). D , Response accuracy as a function of response time (20 ms time bins). Error bars are 95% confidence intervals. The solid line is a logistic fit to the data. The red filled circle is the time that corresponds to 75% accuracy and the error bar through it is the 95% confidence interval.
- Figure 2.
Rapid olfactory decisions. A , Cumulative distributions of response times from all trials for five mice. Each mouse is indicated by a different color. B , Response accuracy as a function of response time. Response times are binned in 20 ms bins (the 60 ms bin corresponds to response times that are 50–70 ms long). Error bars are 95% confidence intervals. The solid lines are logistic fits to the data. The filled circles are the times that correspond to 75% accuracy for each mouse and the error bars through them are the 95% confidence intervals. C , Cumulative distributions of t after: the interval from movement initiation to the onset of the next sniff. D , Response accuracy as a function of t after. All mice reached 75% accuracy before the end of the first sniff. E , Response accuracy for two mice in a control experiment in which both vials had the same odor concentration. F , Response accuracy as a function of t total, the interval from the time of the trigger to movement onset, for three mice. In this experiment, odor delivery was triggered 10–25 ms before inhalation (range of median times across mice). G , Response accuracy as a function of response time for different values of t prior, the interval from the time of the trigger to inhalation onset. Data are from one mouse as an example. Trials were divided into three equal groups according to values of t prior: circles/triangles are the data for the first/last third of the t prior distribution. Top insert, Cumulative distribution of t prior for five mice. H , Response accuracy for the first and the last third of the t prior distribution for response times between 60 and 100 ms (see arrow in G ) for five mice. The values for t prior are the medians for each group. Top insert, Distribution of the pairwise difference in accuracy between the long t prior group and the short t prior group for each individual response time bin in G . Data are pooled across mice. Red circle and red line are the distribution mean and SE, respectively. I , Top insert, Distribution of response times (10 ms bins) for correct trials (blue) and incorrect trials (green) for all mice in A . The p-value is the probability of observing the number of correct trials in each time bin assuming a binomial distribution of correct and incorrect trials and a performance accuracy of 50%.
- Figure 3.
Rapid discriminations for the nontrigeminal stimulant vanillin. A , Response accuracy as a function of response time for the odors vanillin (solid lines) and amyl acetate (dashed line) for two mice. B , Response accuracy as a function of t after for vanillin (solid lines) and amyl acetate (dashed line) for two mice. C , Response accuracy as a function of response time in sniff phase coordinates for vanillin (solid lines) and amyl acetate (dashed lines) for all mice in A and in Figure 2 B. All inhalation/exhalation intervals were stretched or compressed so that they were the length of the average inhalation/exhalation interval computed from all mice. The warped response time is the response time stretched/compressed with its corresponding sniff interval.
- Figure 4.
Correct choices have higher peak velocities than incorrect choices. A , Left, Example velocity traces from seven individual trials (red is unfiltered, black is filtered). Dashed area is magnified at the top. Right, Peak velocity distributions for 5 mice. Here and throughout, different colors indicate different mice, the same as in Figures 2 and 3. Each boxplot shows the median, the 25th and 75th percentiles, and the lowest and highest values in the distribution that were not outliers (two to 10 trials were excluded across mice as outliers). B , Response accuracy as a function of peak velocity for five mice. Solid lines are logistic fits to the data. Error bars are 95% confidence intervals. C , Autocorrelation coefficient averaged across mice (solid line is the mean, gray area is the SEM) for the trial-to-trial sequence of peak velocities (top), choice (rightward or leftward movement; middle), and stimulus (high or low concentration; bottom). Arrows indicate the first trial number for each mouse when three consecutive coefficients, computed from the sequence of peak velocities, are not significantly different from coefficients computed from a randomly shuffled sequence 10,000 times (p > 0.05). D , Response accuracy as a function of response time for different peak velocities for the three mice that had a sufficient number of trials for this analysis. For each mouse, data were divided into three equal groups: low peak velocity (dashed line), medium peak velocity (light solid line), and high peak velocity (dark solid line). Error bars are 95% confidence intervals. Lines are logistic fits to the data.
