Olson Cassady S, Moorjani Aashna, Ragsdale Clifton W
Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois, USA.
Department of Neurobiology, University of Chicago, Chicago, Illinois, USA.
J Comp Neurol. 2025 May;533(5):e70055. doi: 10.1002/cne.70055.
The octopus sucker is a profoundly complex sensorimotor structure. Each of the hundreds of suckers that line the octopus arm can move independently or in concert with one another. These suckers also contain an intricate sensory epithelium, enriched with chemotactile receptors. Much of the massive nervous system embedded in the octopus arm mediates control of the suckers. Each arm houses a large axial nerve cord (ANC), which features local enlargements corresponding to each sucker. There is also a sucker ganglion, a peripheral nervous element, situated in the stalk of every sucker. The structure and function of the sucker ganglion remain obscure. We examined the cellular organization and molecular composition of the sucker ganglion in Octopus bimaculoides. The sucker ganglion has an ellipsoid shape and features an unusual organization: the neuropil of the ganglion is distributed as a cap aborally (away from the sucker) and a small pocket orally (toward the sucker), with neuronal cell bodies concentrated in the space between. Using in situ hybridization, we detected positive expression of sensory (PIEZO) and motor (LHX3 and MNX) neuron markers in the sucker ganglion cell bodies. Nerve fibers spread out from the sucker ganglion, targeting the surrounding sucker musculature and the oral roots extending to the ANC. Our results indicate that the sucker ganglion is composed of both sensory and motor elements and suggest that this ganglion is not a simple relay for the ANC, but facilitates local reflexes for each sucker.
章鱼吸盘是一种极其复杂的感觉运动结构。排列在章鱼触须上的数百个吸盘每个都能独立移动或相互协同运动。这些吸盘还包含一个复杂的感觉上皮，富含化学触觉感受器。章鱼触须中嵌入的大量神经系统的许多部分介导对吸盘的控制。每条触须都有一条粗大的轴向神经索（ANC），其特征是对应于每个吸盘的局部增粗。在每个吸盘的柄部还有一个吸盘神经节，这是一个外周神经元件。吸盘神经节的结构和功能仍然不清楚。我们研究了双斑章鱼吸盘神经节的细胞组织和分子组成。吸盘神经节呈椭圆形，具有一种不同寻常的组织方式：神经节的神经纤维层分布为口面（远离吸盘）的帽状和口侧（朝向吸盘）的一个小袋状，神经元细胞体集中在两者之间的空间。通过原位杂交，我们在吸盘神经节细胞体中检测到感觉（PIEZO）和运动（LHX3和MNX）神经元标记物的阳性表达。神经纤维从吸盘神经节延伸出来，靶向周围的吸盘肌肉组织以及延伸至ANC的口侧根部。我们的结果表明，吸盘神经节由感觉和运动元件组成，并表明这个神经节不是ANC的简单中继站，而是促进每个吸盘的局部反射。
