Octopus Nervous System
As stated previously, the nervous system of an octopus can rival many vertebrates and unlike their molluscan relatives, octopuses' nervous systems are concentrated in their heads rather than being nerve knots or ganglia (Williams 2011). The nervous system is divided morphologically into three parts; the central brain, the optic lobe and the nervous system of the arms; the later two are located outside of the brain capsule and are fairly autonomous systems. The central brain contains 64 lobes, such as the vertical lobe (VL), which is similar to the hippocampus and is the key player in learning and memory. These lobes are lateralized and folded to increase surface ares (Williams 2011). Of the 500 million cells dedicated to an octopuses’ nervous system, 40-45 million are found in the central brain (Hochner 2006).
The optic lobes and locomoter system are both central fused ganglia. The optic lobes are the larger of the two ganglion systems and contain up to 65 million neurons (Edelman and Seth 2009). They are located right under the eyes (Lisieski 2010). Responsible for processing visual signals, researchers also believe the optic lobe is where visual memories are made and stored (Edleman and Seth 2009). In addition, researchers hypothesize the optic lobes are functionally similar to mammalian retinas (Lisieski 2010).
Whereas the central brain and optic lobes have functions and composition similar to vertebrates, the locomotor system is radically different from any system found in vertebrates. Researchers found when a detached tentacle will act in a realistic way, making the mostly autonomous locomotor system vastly different from other sensorimotor systems in vertebrates (Edelman and Seth 2009). The locomotor system, touched on in the section concerning anatomy, is connected to the central brain through a chain of fibers. An extraordinary large amount of neurons are dedicated to the locomotor system, approximately 2/3 of all neurons. In addition to controlling movements, the nervous system of the locomotor system processes sensory information gathered by the chemoreceptors and mechanoreceptors found in the suckers and skin along each tentacle (Hochner 2006).
The nervous system of octopuses is largely unstudied and what researchers have found is only the beginning stages. Yet we can expect more information as science continues using molecular and cellular techniques to explore and explain. The figure below shows a comparison between a human brain, zebra finch brain, and the brain of an Octopus vulgaris. The figure highlights the differences in structures and organizations between the octopus brain and the fairly homologous human and zebra finch brains (Edelman and Seth 2009).
The optic lobes and locomoter system are both central fused ganglia. The optic lobes are the larger of the two ganglion systems and contain up to 65 million neurons (Edelman and Seth 2009). They are located right under the eyes (Lisieski 2010). Responsible for processing visual signals, researchers also believe the optic lobe is where visual memories are made and stored (Edleman and Seth 2009). In addition, researchers hypothesize the optic lobes are functionally similar to mammalian retinas (Lisieski 2010).
Whereas the central brain and optic lobes have functions and composition similar to vertebrates, the locomotor system is radically different from any system found in vertebrates. Researchers found when a detached tentacle will act in a realistic way, making the mostly autonomous locomotor system vastly different from other sensorimotor systems in vertebrates (Edelman and Seth 2009). The locomotor system, touched on in the section concerning anatomy, is connected to the central brain through a chain of fibers. An extraordinary large amount of neurons are dedicated to the locomotor system, approximately 2/3 of all neurons. In addition to controlling movements, the nervous system of the locomotor system processes sensory information gathered by the chemoreceptors and mechanoreceptors found in the suckers and skin along each tentacle (Hochner 2006).
The nervous system of octopuses is largely unstudied and what researchers have found is only the beginning stages. Yet we can expect more information as science continues using molecular and cellular techniques to explore and explain. The figure below shows a comparison between a human brain, zebra finch brain, and the brain of an Octopus vulgaris. The figure highlights the differences in structures and organizations between the octopus brain and the fairly homologous human and zebra finch brains (Edelman and Seth 2009).