Figure 7.

Model of neuronal wiring principles derived from receptive field data superimposed on a three-dimensional reconstruction of the central complex. Input neurons (TL2) have relatively small, contralaterally centered receptive fields, i.e., neurons in the left brain hemisphere have receptive fields centered in the right sky hemisphere (black) and vice versa for the right brain hemisphere (red). CL1 neurons have slightly larger, ipsilaterally centered receptive fields, implying midline crossing connections between TL2 and CL1 neurons (colors indicate the source of polarized light information). CL1 neurons are represented by arrows following the anatomical trajectories of CL1 cells. The smooth arborizations of TB1 neurons (top, projections to the posterior optic tubercle omitted) on either side of the PB-midline provide the potential targets for CL1 cells. Therefore, the bilaterally symmetrical receptive fields of TB1 neurons can be explained by integration of signals from at least two CL1 cells, one from each hemisphere. The morphology of the TB1 neuron is modified from Heinze and Homberg (2007).