A-C: A. Power-spectra of the EODs used as stimuli. For this analysis the EODs were measured next to the tip of the chin appendix of an animal. Single EODs for the three conditions (0, + and—10°) are shown to the right. Note the differences in the positive-to-negative peak ratios and the similarity of the power spectra. B. Exemplary local field potential recorded in the plexiform layer of the medial zone of the ELL in the absence of sensory stimulation. The open triangle below the field potential recording indicates the t₀ reference, while the filled triangle indicates the time when the EOD would have occurred under natural conditions, i.e. the time at which the artificial stimulus was presented. The schematic indicates the receptive field centre of the encountered cell. C. Example of the stimulus protocol. From top to bottom: spikes (AP), EODs and phase of the stimulus. For positive and negative phase shifts two consecutive phase shifts were presented. Each epoch lasted for 30 seconds.

This cell responded with a reproducible de- (+10°) and increase (-10°) of its rate to the phase shifts, whereas first-spike latency was not systematically altered. Here and in the following figures four panels (A-D) are shown. A, C. Raster plots showing the change in spiking when switching from the undistorted (0°) to a phase-shifted (+ or -10°) EOD. Responses to phase shifted EODs are visualized by the coloured background. Significant differences between undistorted and phase-shifted conditions are indicated by the lines to the right (Kruskal-Wallis test with Dunn’s post-hoc analysis, alpha = 0.05). The raster plots on the right side of panels A and C depict the duration of the EODC for the corresponding raster plots. Note that EODC intervals were irregular and longer than the time at which spikes occurred. For better visualisation the raster plots are thus shown to match the longest interval after time zero at which spikes occurred in a given cell. B, D. Peri-stimulus time-histograms (PSTH) summarizing the data shown in A and C, phase shifts are plotted in colour, undistorted EOD-data in black. See for data.

This cell responded reproducibly with an in- (+10°) or decreased (-10°) rate to the phase shifts, whereas first-spike latency was not altered systematically. For the full legend to the panels, refer to .

This cell responded reproducibly with an in- (+10°) or decreased (-10°) rate to the phase shifts, whereas first-spike latency was not altered significantly. For the full legend to the panels, refer to . See for data.

This cell responses reproducibly with a de- (10°) or an increased (-10°) rate to the phase shifts, whereas first-spike latency was not altered (not shown). For the full legend to the panels, refer to . See for data.

Solid symbols show data from cells the DLZ and open symbols show data from cells in the MZ with circles indicating data from I-cells and squares indicating data from E-cells. Responses to positive phase shifts are marked in red, while responses to negative shifts are marked in blue. Error bars represent standard deviations. Note that similar cell types respond oppositely in both zones. See for data.

A. Low-magnification photomicrograph showing an ELL cross-section following a biocytin injection in the medial part of the medial zone. The section has been processed following the DAB procedure and counter stained with cresyl violet. The three zones are indicated on the slide and the different layers of the zones are indicated by the black lines at the borders between the MZ and DLZ. Note that the commissural projection connects the medial and dorsolateral zone such that the medial parts of the MZ connect with the lateral part of the DLZ. Likewise the lateral MZ is connected with the medial DLZ (see B, C). As the dorso-ventral topography of the sensory surface is represented along the medio-lateral axis in the MZ and the lateral to medial axis in the DLZ, this shows that somatotopically corresponding zones of the maps are connected. The higher magnification inset on the left shows the area surrounded by the stippled line in the DLZ. The red arrows point towards two retrogradely labelled somata in the granular layer. Abbreviations: deepf, deep fibre layer; gang, ganglionic layer; gran, granular layer; mol, molecular layer; plex, plexiform layer. B. Photomicrograph showing an injection site in the lateral part of the MZ using neurobiotin 488 (shown in green) and a fluorescent Nissl counterstain (blue). C. Interzonal projection to the DLZ originating from the injection shown in B. Note that in addition to the strong labelling of fibres some weakly stained large somata are present in the interzonal layer. The schematic inset in A and B shows a cross-section of the medulla with the injection site and the region where the close-up were taken indicated in green. deep, deep fibre layer; ggl, ganglionic layer, gran, granular layer, inter, intermediate layer; plex, plexiform layer.