Hemispheric specialization of the brain and behavioral asymmetries have long been thought to represent a unique human trait. Recent studies show that we share brain lateralization with many species of vertebrates. Structural asymmetries have been well documented, especially for invertebrates, yet so far an ethological approach is lacking. Now, lateral asymmetry of eye use in an invertebrate, the octopus, has been documented on the individual level. So lateral asymmetry seems to be an early evolutionary feature not limited to vertebrates. Because of the independent evolution of the octopus brain, octopus represents an outgroup to test evolutionary hypotheses on the origin of behavioral and morphological lateralization. We intend to use a combined, ethological and neuroanatomical approach to study behavioral and morphological asymmetries in Octopus vulgaris. Because of the short life spans of the individuals the Octopus system offers the unique possibility to study brain asymmetry of specific behaviorally well documented individuals. One aim will be to extend our study to the population level to include this highly evolved invertebrate in the discussion on evolutionary relevant mechanisms of lateralization, as lateralization at the population level is seen to be evidence that evolutionary processes have been at work. The second part of this study will correlate anatomical findings with performance measured in living subjects, using advanced MRI, episcopic 3-D reconstruction, and morphometrical analysis. This project was performed in cooperation with Ruth Byrne at the KLI.