Differences in MT cell responses between fast and slow sniff cycles. Differences in MT cell responses between fast and slow sniff cycles. A, Schematic of the experiment. A head-fixed mouse implanted with intranasal cannula and a multi-electrode chamber was positioned in front of the odor delivery port. Left, Pressure wave form of a typical breathing cycle. Red dots indicate the inhalation onsets and offsets. The blue line is the parabolic fit to the first minimum after the inhalation onset. The sniff offset was defined as the second zero crossing of the parabolic fit. The gray shaded area marks the inhalation interval. B, Distribution of different response types observed in the data. Next to the pie chart are examples of initially excitatory (red) and initially inhibitory (blue) responses. Gray lines represent spontaneous activity. C, Sniff duration histogram for all mice averaged across multiple sessions for the 1st odorized sniff cycle. Sniffs are split into two groups: fast (<221 ms; orange) and slow (>221 ms; blue). D, Raster (top panels) and PSTH (bottom panels) plots of the first odorized sniff cycle for four MT cells in response to an odor stimulus. Trials in the raster plots are ordered bottom to top by the increase in the duration of sniff cycle. Gray line shows end of the sniff cycle. Raster plots and PSTHs for fast and slow sniffs are marked by orange and blue colors, respectively. Gray PSTHs are average spontaneous activity of MT cells during all unodorized sniffs. Roman Shusterman et al. eNeuro 2018;5:ENEURO.0149-18.2018 ©2018 by Society for Neuroscience