Cephalopod brains: promising preparations for brain physiology

The brains of cephalopods are the most sophisticated brains of all invertebrates, and their gross anatomy and neuronal pathways are well known. Much is also known in cephalopods about learning and memory functions. Yet physiological recordings from cephalopod brains are scanty. However, three preparations have been developed and are now available for experiments on cephalopod brain physiology: (i) a brain slice preparation that allows intracellular recordings from identified brain neurones, (ii) an intact animal preparation that permits multiple electrode recordings of spikes and compound field potentials from unanaesthetized and unrestrained cuttlefish, and (iii) mapping of metabolic brain activity with [¹⁴C]deoxyglucose. These preparations are complementary and allow a variety of physiological experiments to be done. With further improvements of the techniques and in combination with the morphological information that already exists on pathways in the cephalopod brain, these new preparations are promising tools for cephalopod brain physiology. They may even serve as supplementary or alternative invertebrate preparations for vertebrate research. These three preparations are complementary and allow a variety of physiological experiments to be done. This chapter briefly describes the preparations, and discusses the impact they may have on future research on cephalopod and vertebrate brain functions.