PMC

The structure (I) and photo (II) of the test-bed: (a) End cover. (b) Loudspeaker I. (c) Left clapboard. (d) Loudspeaker II. (e) Shell. (f) Motor. (g) Right clapboard. (h) Rubber springs. (i) Supports.

Map of the tributaries surrounding the lower St. Johns River that were surveyed as part of our study (white areas). From northeast to south: Clapboard Creek, Dunn Creek, Broward River, Trout River, Arlington River, Ortega River, Doctors Lake, Julington Creek, and Black Creek. The map was created with ArcGIS Pro 2.6 (https://arcgis.pro/).

Experimental design. (A) Participants judged whether a beep and a flash were simultaneous or successive. The beep always arrived at the participant ∼210 ms after a trigger signal was received at the “clapboard,” a device which generates a beep and a flash. On a given trial, a flash could occur within a 200 ms window around the beep at nine possible offsets (multiples of 50 ms). Zero millisecond corresponds to when the beep and the flash physically arrived at the participant at the same time. (B) The beep/flash pair was either presented randomly in a 4 s window after the last response (Passive), or triggered by the participant by a button press (Active). (C) The beep and the flash were presented at two different distance conditions: Near (clapboard receiver located 0.5 m from participant) or Far (30 m from participant). Stimulus arrival times at the participant were held constant in the Near and Far conditions (i.e., the slower speed of sound was taken into account so that offsets represent the physical arrival time of the signals at the participant).

Marginal and carpet glial cells. Confocal analysis of third instar larval eye imaginal discs. Single glial cells are marked with anti-GFP antibodies (green). Glia cell nuclei are stained for Repo expression (red) and photoreceptor neurons are marked with anti-HRP antibodies (blue). A–E, Anterior is to the top. A, 3D reconstruction of an eye imaginal disc. At the margin of the eye disc, a small clone of glial cells is marked (arrowheads). B, C, Single confocal sections of this glial clone show that marginal glial cells (5) display an elongated, clapboard like shape. No contacts to axons can be detected. D, D′, Every eye disc has two large, flat carpet cells of which one is labeled in this eye disc. The carpet glial nucleus can be easily identified according to its size (arrow; see also arrows in ). The cytoplasmic extensions of the carpet cells cover half of the eye disc. E, Triple-stained specimen showing the relation of the carpet cell to axons and other glial cells. The dashed line indicates the orthogonal section shown in F. F–F‴, Orthogonal section shows that the so-called carpet cells separate basally localized nuclei from axons (blue) and more apical located glial nuclei.