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The pattern of muscle responses associated with catching a ball in the presence of vision was investigated by independently varying the height of the drop and the mass of the ball. It was found that the anticipatory EMG responses comprised early and late components. The early components were produced at a roughly constant latency (about 130 msec) from the(More)
We address the problem of whether and how adaptation to suppression of visual information occurs in catching behavior. To this end, subjects were provided with advance information about the height of fall and the mass of a ball and an auditory cue signaled the time of release. Adaptation did occur, as indicated by the unimpaired ability to catch the ball(More)
The dynamics of the horizontal vestibuloocular reflex (VOR) were determined in the dark prior to and at various time periods after unilateral removal of the vestibular nerve. One chronic group, consisting of cats that were operated at the age of 6 weeks or as adults, was studied 10.5 to 22 months later; an adult-operated group was measured 1-244 days(More)
Horizontal optokinetic eye nystagmus (OKN) and after nystagmus (OKAN) were recorded in the alert cat (head restrained) in response to velocity steps and sinusoidal optokinetic stimuli. A strong dependency of OKN performance on stimulus pattern was found: responses were most regular and gain was high over a large range of stimulus velocities when the(More)
The posture of cats trained to stand freely on a platform was studied during static tilts (up to +/- 30 degrees). Vertical projection of the center of mass on the support surface, as well as limb orientation in space and degree of limb flexion, varied minimally with platform tilt angle. The limbs' main axes were kept almost lined up with the vertical. This(More)
Cats trained to stand on a platform exhibit postural responses to dynamic tilting that appear to be based on an internal reference model of body geometry and the environment rather than directly on sensory inputs, as in a classical reflex chain. The data presented show an independent control of global variables of limb geometry, the length and the(More)
1. It has previously been demonstrated that a set of geometric and kinetic parameters are invariant in cats standing at their preferred interfoot distance and weight distribution. Thus the length and the angle of orientation relative to the vertical of each limb axis remain approximately constant when the supporting platform is tilted in the sagittal plane.(More)
1. Global geometric variables represent high-order parameters in the control of cat posture. In particular, limb length and orientation are accurately controlled in response to tilts of the support platform. There is now electrophysiological evidence, obtained in anesthetized cats, that spinal sensory neurons projecting to the cerebellum are broadly tuned(More)
  • C Maioli
  • 1988
To account for the oscillatory behavior of the optokinetic after-nystagmus (OKAN), a nonlinear model of the optokinetic system is proposed here that includes 2 first-order storage elements interconnected in a negative feedback loop. The adequacy of the model is tested by comparing its predictions with experimental data available in the literature. In(More)