Fig. 3: Goal coding in monarch butterflies.
From: Neural representation of goal direction in the monarch butterfly brain
a Hypothesized tuning of a GD (blue, purple) and a HD (green) neuron in reponse to compass perturbations and aversive conditioning. The angular tuning of GD neurons was expected to change only in response to aversive conditioning, while the angular tuning of HD neurons should change only during compass perturbation. b Angular tuning of GD (n = 20; top) and HD (n = 13; bottom) neurons measured in response to compass perturbations (two left columns) and aversive conditioning (two right columns). Neurons are ordered according to their pfds before compass perturbation and conditioning. Each neuron’s firing rate (FR) is normalized against its peak firing rate. c Ratio of changes in pfds and changes in heading for GD neurons (n = 20) during compass perturbations (blue) and during conditioning (purple). Ratios close to one indicate a strong association between angular tuning and behavior. The neurons only changed their pfd when the goal direction was reset during conditioning (p = 0.0121, W = 132, n = 20, two-sided Wilcoxon matched-pairs signed-rank test). Box plots indicate median (middle line), 25th, 75th percentile (box), and 5th and 95th percentile (whiskers). d Correlation of angular tuning before and after compass perturbations (p = 0.0106, t = 2.72) and (e) before and after conditioning (p < 10−5, t = 5.89) for GD (blue, n = 20) and HD (green, n = 13) neurons (two-sided unpaired t-test). f The goal offset before (orange) and after (red) conditioning describes the difference between the animal’s goal direction (magenta lines) and the neuron’s pfd (black lines). The change in pfd of a GD neuron was tightly associated with the change in goal direction resulting in a consistent goal offset of about 180°. g Differences in goal offsets before (left) and after (right) conditioning for GD (blue) and HD (green) neurons (p = 0.0005 , U = 60, n = 20 GD and 13 HD neurons, two-sided Mann–Whitney test). Error bars in (d), (e), and (g) represent the interquartile range (middle line indicates the median). Source data file: datasource.xlsx Fig. 3.
