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. Author manuscript; available in PMC: 2014 Sep 1.
Published in final edited form as: J Membr Biol. 2013 Aug 22;246(9):679–688. doi: 10.1007/s00232-013-9584-1

Figure 2.

Figure 2

A. Multiple-site optical recording of neural responses to upper spinal cord stimulation in a 7-day old embryonic chick brainstem-spinal cord preparation. The preparation was stained with a merocyanine-rhodanine absorption dye, NK2761. The optical signals evoked by electrical stimulation (200 μA/1 msec) were recorded simultaneously from 464 contiguous regions of the preparation with a magnification of ×4 (an objective) ×1.67 (an eyepiece). The direction of the arrow in the lower right indicates an increase in transmitted light intensity (a decrease in dye absorption), and the length of the arrow represents the stated value of the fractional change (the change in light intensity divided by DC-background intensity). Electrical stimulation elicited a propagating depolarization wave in the spinal cord and the brainstem. An illustration of the preparation is shown in the lower right, in which the detected area is marked with a gray hexagon. The recording was made in a single sweep. B. Enlarged traces of the optical signals detected from four regions indicated by a–d in A.