Figure 6.
AC Neurons Coding for Intermediate Frequencies Distinguish Sounds of the Difficult Task
(A) Sketch of intrinsic imaging setup and averaged re-aligned intrinsic imaging maps sampled over 12 mice for 4-, 8-, and 16-kHz pure tones and FM sweeps. White lines and arrows indicate the main tonotopic fields, as in Figure 5A.
(B) Sketch of 2-photon setup and picture of the AC surface with the localization of calcium imaging fields of view (FoVs) for a sample mouse. A magnification of FoV 5 is shown on the right. Raw calcium traces (scale bar: 50% Δf/f0) and a pure tone tuning curve (70 dB SPL) for a sample neuron are shown on the bottom. The calcium imaging setup is sketched on the left.
(C) Magnification of cranial window shown in (B) with the contours of intrinsic imaging responses to 4- and 8-kHz pure tones (left) and the locations of all significantly responding neurons, which do not respond to both 4-kHz and 4- to 12-kHz (discriminative neurons; see STAR Methods) recorded with 2-photon calcium imaging (non-discriminative neurons removed). Color code corresponds to their preferred frequency over the same sounds used during intrinsic imaging experiments. Circle diameters are proportional to the mean deconvolved calcium response for the best frequency sound over 20 repetitions (right). The dashed line indicates the position of the main tonotopic fields.
(D) Red dots: correlation of the pooled intrinsic response maps of the FM sweeps with pooled maps of four different pure tones (n = 12 mice for the aligned maps). Black dots: correlation between the population vector responses of the FM sweeps and of various pure tones is shown (time bin 0 to 1 s after sound onset; from 5,157 significantly responding neurons over 30 sessions in 5 mice). Intrinsic: max = 1; min 0.75. Calcium imaging: max = 0.25; min = 0.
(E) Fraction of neurons that respond significantly to the FM sweep (n = 520 neurons; Wilcoxon rank-sum test; α = 0.01) from the pool of significantly responding neurons (discriminative neurons; n = 4,692 neurons).