Figure 6

Responses to visual stimuli. (a) While individual zebrafish larvae display considerable variability, larvae typically move in the same direction as moving lines projected through the bottom of a white ProxiPlate. (b) A consistent visual response can be measured by averaging the response of 12 larvae, i.e. each line in the panel represents a row of 12 larvae. (c) Activity levels were significantly lower in the pooled DMSO-treated group (N = 191 larvae), as compared to the pooled untreated group (N = 143 larvae, chi-squared). Activity levels at individual days are not significantly different from a pooled average, which includes all untreated or all DMSO-treated controls (chi-squared test). (d) Larvae treated with 80 µM diazepam (Valium) are immotile and appear dark in the white plates. (e) Larvae treated with 40–60 µM diazepam display a strongly suppressed response to visual stimuli (chi-squared test, p < 0.01/5, to correct for multiple comparisons vs. the DMSO-treated control (c)). Error bars indicate the standard error of the mean. Visual response (E-O) = the average percentage of larvae in the upper half of the well during the Even periods (period 4, 6, 8, 10 and 12) minus the average percentage of larvae in the upper half of the well during the Odd periods (period 3, 5, 7, 9 and 11).