BEHAVIOR AND CNS INTEGRATION 



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Figure 3 Nissl -stained sections cut transversely, 600 

 jum apart, through the midbrains of a normal nurse 

 shark (left) and NS-143 (right), indicating a com- 

 plete tectal ablation in the latter. Sections are arranged 

 rostrocaudally (A-D) with the following abbreviations: 

 TeO, optic tectum; AP, pretectal area; GL, lateral 

 geniculate nucleus (dorsolateral optic nucleus); CTh, 

 central thalamic nucleus. 



function somewhat. This is further suggested by the general behavior of 

 subject NS-143, observed during the recovery period. At first the shark re- 

 mained relatively inactive, lying on the bottom of the pool and occasionally 



