. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Left Walking 1 2 3 Time in Seconds. A Cell A, Left Connective Figure 2. (A) Extension phases of left and right 2nd to 5th legs during a short sequence of walking to the left by a crab. The extracellular recording shows cell A in the left esophageal connective. The series of bursts of activity are more related to slight angular excursions of the body () than to the gait pattern. is the clockwise angular displacement of the body of the crab around the horizontal longitudinal axis. (B) The effect of cutting the right esophageal
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Left Walking 1 2 3 Time in Seconds. A Cell A, Left Connective Figure 2. (A) Extension phases of left and right 2nd to 5th legs during a short sequence of walking to the left by a crab. The extracellular recording shows cell A in the left esophageal connective. The series of bursts of activity are more related to slight angular excursions of the body () than to the gait pattern. is the clockwise angular displacement of the body of the crab around the horizontal longitudinal axis. (B) The effect of cutting the right esophageal connective on locomotion in the crab Carcinus maenas. Gait alters and the crab prefers walking left. Regardless of the direction of walking, the crab always turns counterclockwise (Bethe, 1897). This is the direction that optimally excites Cell B in the right connective. Electrical stimulation of the cut end of the connective will straighten or reverse the counterclockwise movement. locomotion. Fraser (1982) points out that "where a behavior involves vectorial output in more than one dimension, or where feedback loops are involved, then the output mea- sured by displacement of appendages or by muscle activity is no longer an adequate measure of the behavior ... in terms of understanding the underlying neural activity, loco- motion in crabs may be better described in terms of com- ponents of force and torque in the planes used by the equilibrium cells rather than in terms of the gaits em- ; The angular displacements of crabs have been monitored in orthogonal planes with a miniature triaxial accelerometer. Although proprioceptor input affects the activity of the interneurons, their outputs in free-walking animals are not particularly complicated (Fraser, unpubl. data; Fraser. 1995). Interestingly, Cruse et al. (1998) and Schmitz (2001) state that in the stick insect there is little evidence for a central pattern generator. Instead sensory information de- rived f
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
