Inner Neurons of Isthmi Nuclei are Semi-Topographically Organized Figure 4 . From Rana pipiens . V - ventral. Location of the General Behavioral Deficit after Lesioning the Nucleus Isthmus on the Left Side of the Brain. Figure 5 .
Outer numbers represent the order of placing a cricket in each radial sector for two minutes.
Notice the generally greater number of responses when the stimulus is novel and the lack of responses in the lower right quadrant. Size of Scotoma vs. the Completness of Nucleus Isthmus Lesion Figure 6 . The Tectal Visual Fields in the Scotoma Region Increase in Size Figure 7. The left column shows the neural visual fields in the Rana pipiens tectum unaffected by nucleus isthmus lesions while the column on the right shows the mirror image visual fields in the scotoma area from the opposite sided tectum which was affected by the lesions. Provided by the Nucleus Isthmus Figure 8 .