Dynamic Model of the Octopus Arm. II. Control of Reaching Movements

Journal of Neurophysiology - Tập 94 Số 2 - Trang 1459-1468 - 2005
Yoram Yekutieli1, Roni Sagiv-Zohar, Binyamin Hochner, Tamar Flash
1Department of Neurobiology, The Weizmann Institute of Science, Israel

Tóm tắt

The dynamic model of the octopus arm described in the first paper of this 2-part series was used here to investigate the neural strategies used for controlling the reaching movements of the octopus arm. These are stereotypical extension movements used to reach toward an object. In the dynamic model, sending a simple propagating neural activation signal to contract all muscles along the arm produced an arm extension with kinematic properties similar to those of natural movements. Control of only 2 parameters fully specified the extension movement: the amplitude of the activation signal (leading to the generation of muscle force) and the activation traveling time (the time the activation wave takes to travel along the arm). We found that the same kinematics could be achieved by applying activation signals with different activation amplitudes all exceeding some minimal level. This suggests that the octopus arm could use minimal amplitudes of activation to generate the minimal muscle forces required for the production of the desired kinematics. Larger-amplitude signals would generate larger forces that increase the arm’s stability against perturbations without changing the kinematic characteristics. The robustness of this phenomenon was demonstrated by examining activation signals with either a constant or a bell-shaped velocity profile. Our modeling suggests that the octopus arm biomechanics may allow independent control of kinematics and resistance to perturbation during arm extension movements.

Từ khóa


Tài liệu tham khảo

10.1523/JNEUROSCI.05-09-02318.1985

10.1109/70.294209

10.1016/0163-1047(90)90441-8

10.1523/JNEUROSCI.18-15-05976.1998

10.1523/JNEUROSCI.16-22-07297.1996

10.1109/TAC.1984.1103644

10.1007/BF00355754

Hollerbach JM.Fundamentals of motor behavior. In:Visual Cognition and Action, edited by Osherson, DN, Kosslyn, SM, and Hollerbach JM. Cambridge, MA: MIT Press, 1990, p. 151–182.

10.1007/BF00353957

10.1111/j.1096-3642.1985.tb01178.x

10.1152/jn.2000.83.3.1315

10.1007/BF00236911

10.1152/jn.00383.2002

10.1126/science.1060976

10.1007/s002210100797

10.1038/255727a0

Wells MJ.Octopus.London: Chapman & Hall, 1978.

Wells MJand Wells J.The function of the brain of octopus in tactile discrimination.J Exp Biol34: 131–142, 1957.

10.1098/rspb.1965.0025

Thông tin
Thông tin xuất bản

Journal of Neurophysiology

Tập 94 Số 2

1459-1468

Thông tin tác giả