Figure 3.

Statistical analysis of innervation bias and afferent neuronal receptive fields. A, In a plot of the weight of evidence for a biased model (W) against larval age, the ordinate represents the average weight of evidence contributed by a single neuromast at the given time. Summing the results over the ensemble of neuromasts yields a total weight of evidence of 375 db. B, Given that there is strong evidence for orientation selectivity, the parameter ω reflects the degree to which the neuron's choice of hair cells is biased. To illustrate the degree of bias as a function of larval age, the results have been expressed as means of the probability of |ω − 0.5| + 0.5, so that the ordinate reflects increasing bias. The error bars represent SDs. C, A histogram illustrating the fraction of a neuromast's hair cells innervated by the labeled fiber indicates that 84% of the neuromasts studied had 50% or fewer hair cells innervated. D, A plot of the number of neurons with the indicated receptive-field sizes demonstrates the preponderance of fibers innervating one or two neuromasts. E, The mean number of neuromasts innervated by a single afferent is essentially constant over the range of larval ages investigated. The error bars represent SEMs. F, The distribution of neuromasts per neuron demonstrates an excess of posteriorly biased (black) over anteriorly biased (gray) neurons.