Figure 3. Arousal Suppresses Visual Responses in Individual Retinal Boutons in the dLGN.
(A) Left: example raw fluorescence image of retinal axons and axonal boutons in the dLGN, 115 μm below the window. M, medial; L, lateral; A, anterior; P, posterior. Right: average visually evoked calcium responses of RGC boutons from the orange subregion.
(B) Reliable single-trial visual responses of an individual RGC bouton (outlined in A) to presentations of gratings drifting along the bouton’s preferred direction (45°, arrow; responses in B–J involve 0.08 cpd gratings).
(C) Single-trial visual response magnitudes in (B) were negatively correlated with pupil area (r = −0.44, p < 10−4). Green and magenta indicate low and high arousal states.
(D) Single-trial response time courses (black: means) for this bouton during low or high arousal states.
(E) Direction tuning curves (mean ± SEM) for this bouton during low or high arousal. 0°: roughly nasal-to-temporal motion on the LCD monitor. 90°: upward motion.
Arrows: estimated nasal-temporal (N-T) and dorsal-ventral (D-V) axes, with the head in a typical ambulatory posture.
(F) Visual responses of most direction-selective (DS) boutons (78.3%, 3,386/4,324 boutons from 22 fields of view [FOV], 5 mice) were negatively correlated with arousal. Median correlation: −0.246. Red line: no correlation. Green: cumulative distribution.
(G) Most DS boutons (82.1%, 2,971/3,619 boutons from 22 FOV, 5 mice) had negative MIs (see STAR Methods; median: −0.336).
(H) Single-trial responses and direction tuning curves across arousal states, from example direction-selective (DS), axis-selective (AS), broadly tuned (BrT), and suppressed-by-contrast (SbC) boutons. The example BrT and SbC boutons were suppressed by arousal, while the example AS bouton was enhanced.
(I) Cumulative distributions of modulation indices for different bouton categories (N = 3,619 DS; 3,609 AS; 3,692 BrT; and 1,521 SbC boutons). For DS, AS, BrT, and SbC boutons, 82.1%, 68.6%, 63.6%, and 58.2% of the boutons had negative MI values, respectively. MI distributions differed significantly across pairs of bouton categories (all p values < 10−4, Kolmogorov-Smirnov tests with Bonferroni correction). Inset: area under the curve (AUC) for the receiver operating characteristic (ROC) curve for pairs of MI distributions (STAR Methods).
(J) Fraction of boutons per category with significantly enhanced, not significantly (N.S.) enhanced, not significantly suppressed, or significantly suppressed responses. Black dashed lines indicate the median fractions of significantly enhanced or significantly suppressed boutons in shuffled data (1,000 shuffles; gray dashed lines: 95% confidence intervals; STAR methods).
See also Figure S3.