The Cor32 and Cor34 experiments, performed by David Senseman of UTSA, measure the response of the turtle visual cortex in an intact visual system to various spot and flash stimuli by using voltage sensitive dye imaging. Fig. 1 shows the experimental apparatus for VSD imaging using absorption voltage-sensitive dyes. The amount of light passing through the tissue that has been stained with such a voltage-sensitive dye bears an inverse relationship with the voltage of the tissue.
Fig. 1: Voltage-sensitive dye imaging apparaus |
The experiment uses a hexagonal array of 464 detectors positioned as shown in the Fig. 2. The entire brain with the intact eye is first removed and stained with a voltage-sensitive absorption dye. The visual cortex is sliced so that it can be unrolled to a flat sheet, taking care not to cut any connections in the visual pathway.
Fig. 2: Recording of voltage response in turtle visual cortex |
Senseman (1996, 1999) provide additional information about the VSD imaging technique.
References:
Senseman DM (1996)
Correspondence between visually evoked voltage-sensitive dye
signals and synaptic activity recorded in cortical pyramid
cells with intracellular microelectrodes
Visual Neurosci 13:963–977
Senseman DM (1999)
Spatiotemporal structure of depolarization spread
in cortical pyramidal cell populations evoked by diff
use retinal light flashes
Visual Neurosci 16:65–79