These species also cover ecologically diverse life histories, representing benthic, nectobenthic and nectonic animals. Cephalopods are animals with Vandetanib mechanism of action advanced cognitive skills and a complex repertoire of behavioral abilities [3,45]. Their brains are comparable both in size and complexity with those of vertebrates, and have been the focus of a number of studies on the neurobiology of behavior [46]. In particular, they have served as models for the cellular and systems circuitry of learning and memory [4,9]. Historically, Octopus vulgaris has been a key species for this work through studies of anatomy [9], behavior following lesions and brain stimulation [3,4,47] and cellular neurophysiology [48,49]. O. vulgaris has also served as an attractive model for neuroendocrine studies in invertebrates [5,50].
Recently, Octopus bimaculoides (California Two-spot Octopus) has emerged as a model system for cephalopod biology. The large size of O. bimaculoides eggs grants unique access to early embryonic stages, making this species a prime candidate for future genetic and developmental studies. The hardiness, ready availability in the United States and easy husbandry of adult O. bimaculoides [51] add to the appeal of this model species. The deadly venom of blue-ringed octopus Hapalochlaena maculosa makes this species of interest for study of the evolution and regulation of toxicity within octopods [1]. Comparative studies of these octopus species would illuminate the bases of both their shared characteristics as well as those of their divergent features.
Additionally, these species have essentially non-overlapping geographic distributions, providing animal accessibility to cephalopod researchers globally. Within the decapodiforms, Sepia and Loligo are the most studied genera. Historically, Sepia officinalis has been a key cephalopod for neurobiological research, and is a critical species in global fisheries. S. officinalis possesses a complex chromatophore network for countershading, camouflage and communication [3,52,53]. Its internal calcified shell supplies buoyancy and the effect of global climate changes on this structure has become a focus of recent study [54,55]. S. officinalis is emerging as a particularly versatile model organism in eco-evo-devo studies [56]. As a practical matter, S. officinalis eggs are voluminous, and easily collected, maintained and reared in the laboratory [57].
The morphological events in S. officinalis embryogenesis are well described in the literature [58-61]. Loligo, and particularly its giant fiber system, has served as the fundamental basis for our understanding of nerve impulse conduction. The GSK-3 giant synapse system has recently been employed as a biomedical model of neurological disease [62]. Loligo is one of the most important groups for cephalopod fisheries in the North Atlantic [8].