CYTOCHROME-OXIDASE ACTIVITY REVEALS PARCELLATIONS OF THE PIGEONS ECTOSTRIATUM

THE endogenous cytochrome oxidase activity of the pigeon's ectostriatu m, the primary telencephalic structure of the tectofugal visual pathwa y, was histochemically demonstrated and a heterogeneous distribution o f the reaction product was observed. In cross-sections the medial, cen tral and ventrolateral parts of the ectostriatum showed high levels of activity while the centroventral and dorsolateral ectostriatum remain ed weakly labelled. Only slight left-right and interindividual variati ons were found in the pattern of labelling. These data demonstrate for the first time anatomical subdivisions within the ectostriatal core a nd open the possibility of functional parcellations within this struct ure.