Fig. 6. Bar graph illustrating differences in the spike responses of 12 Type I neurons following the onset of water flowing past the antennular flagellum in the PD direction (filled bar) and in the DP direction (open bar). Data represent the mean number of spikes following stimulus presentations (± 1 s.e.m.); the number of stimulus presentation pairs from which the means were calculated for each preparation was between 4 and 27. Statistical significance of the differences between the means is P<0.0025. The flow rate in the DP direction in each experiment was normalized to the PD flow rate. The mean value for flow rate obtained across all experiments was 1.12±0.06 (± s.e.m.).