Fig. 4

Biased turning was attenuated by the ketogenic diet (KD). A Diagram and the calculation formula for the turning bias index. The changes in the left or right traveling directions were calculated every five frames (every 0.25 s) across all trajectories and expressed as radians. Positive radian values represent left (anticlockwise) turning, and negative values indicate right turning. The ratio between the numbers of clockwise and anticlockwise turns was used as the turning rate (1–infinity, positive value). B Turning biases of surface fish (left) and cavefish (right). There was no difference between CD and KD feeding in surface fish, whereas the turning index in CD-fed cavefish was larger than in KD-fed cavefish (see week 6). The generalized linear model followed by post hoc Holm’s correction was applied for the statistical tests. Bars represent the data mean and whiskers represent ± standard error of the mean. Dots indicate individual data. N = 20 for all groups. *: P < 0.05, **: P < 0.01, ***: P < 0.001. All detailed statistical data are available in Additional file 3