Cuttlefish, like humans, appear to process different types of ecological information through different parts of the brain, according to a new study by Alexandra Schnell of the University of Caen and colleagues, including Roger Hanlon, senior scientist at the Marine Biological Laboratory.
“The brain has evolved so that the two sides of the brain are specialized to process different types of information,” says Schnell. “This phenomenon, known as brain lateralization, is widespread across vertebrate species. Typically the left brain hemisphere is specialized to control routine behaviors, such as finding food, and the right brain hemisphere detects and responds to unexpected stimuli, such as predators. But little research has been conducted to test whether invertebrate species share this general pattern of lateralization,” she says.
Cuttlefish, like most invertebrates, lack obvious left and right brain hemispheres. However, they do possess strikingly large paired structures of the central nervous system – such as paired eyes and paired optic lobes.
The team found that cuttlefish predominately used their left visual field to scan for predators and their right visual field to search for prey. These results indicate that each optic lobe — brain structures implicated in visual processing — is specialized for the control of different ecological activities.
This study provides the first empirical evidence of lateralization homology between invertebrates and vertebrates, Schnell says. “Given that cuttlefish share the basic plan of lateralization with vertebrates suggests that simply possessing paired sense organs may be enough to drive the evolution of a lateralized brain.”
Schnell, A.K., Hanlon, R.T., Benkada, A, Jozet-Alves, C. (2016). Lateralization of eye use in cuttlefish: opposite direction for anti-predatory and predatory behaviors. Frontiers in Physiology, doi: 10.3389/fphys.2016.00620