Control of postural reactions in the dog: The role of the dorsal column feedback pathway

Reynolds, PJ; Talbott, Richard E.; Brookhart, John M.

doi:10.1016/0006-8993(72)90122-9

Cited by 20 publications

(9 citation statements)

References 12 publications

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“…If this explanation is correct, it is quite reasonable that the early force changes, with latencies less than 75 msec, would be very similar for the same dog over time and over several dogs which were all of the same general body conformation. Since the dogs used by Reynolds et al (1972) were not uniform in size and shape, the morphological differences may account for the greater between-dog variability found in that study.…”

Section: Discussionmentioning

confidence: 82%

“…In previous studies from this laboratory, a high degree of replicability was noted in the postural response to step displacement (Mori & Brookhart, 1968;Brookhart et al 1970). Later studies, utilizing similar virtual steps as the input, led to results which were more variable (Reynolds et al 1972;Cross, 1973;R. E. Talbott, unpublished).…”

Section: Discussionmentioning

confidence: 91%

“…The other factor affecting the variability in the step displacement experiments was the choice of quantities to be measured. The studies of Reynolds et al (1972) and R. E. Talbott (unpublished) concentrated on changes in joint angles as the important output variables. Cross's (1973) study showed, however, that the distributions of effort (torque) could be shifted among the various joints without leading to movement.…”

Section: Discussionmentioning

confidence: 99%

“…The critical difference between the two techniques shows up when the dogs are subjected to experimental modification, such as blindfolding (Talbott, 1974) or surgical intervention. Whereas the step response data from dogs with transacted dorsal columns was difficult to interpret (Reynolds et al 1972), data from the same dogs responding to sinusoidal displacement led to clear differentiation between normal and experimental conditions (R. E. Talbott, unpublished). A high level of consistency in the results was achieved by changing from virtual step displacement to continuous sinusoidal oscillation.…”

Section: Discussionmentioning

confidence: 99%

“…Blockade of afferents from the paws and the limb joints of a dog was found to cause minimal alteration in the external signs of a postural adjustment to the step displacement such as could be 288 NORMAL DOG SINUSOIDAL RESPONSE measured from changes in vertical force or limb position ; R. E. Talbott, unpublished). Chronic section of the dorsal columns in dogs was also remarkably ineffective for permanently modifying the postural reactions engendered by a step displacement (Reynolds, Talbott & Brookhart, 1972).…”

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confidence: 94%

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The postural response of normal dogs to sinusoidal displacement

Brookhart¹,

Talbott²

1974

The Journal of Physiology

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SUMMARY1. Normal dogs were trained to adopt a laterally symmetric stance on a horizontal platform. Sinusoidal oscillation of the platform in the cephalocaudal direction caused the dogs to adopt a strategy of response which would keep them from falling down during the period of imposed motion or perturbation.2. A Fourier analysis of the response variables provided a quantitative measure of the distortion in the induced movement at the various hind leg joints and in the motion of the body. Certain aspects of the distortion could be accounted for by recognized random events such as drift and panting. The remainder of the distortion was task related and therefore provided evidence that the dog's postural control system behaved essentially as a non-linear system.3. The motion of the body was less distorted than the motion at the joints. The frequency response of the body motion resembled that of a second order linear system, but the amplitude of the body motion did not vary in constant proportion with changes in the amplitude of the input. Further, the phase relation between body motion and platform motion was not constant when the amplitude of the input was changed. Therefore, it was concluded that the control of the body position was probably non-linearly related to the input disturbance but that the low pass filter characteristics tended to minimize the appearance of distortion in that system output.4. Control of the position of the hind limb is related to the control of the torque generated at the hind limb joints. To the extent that joint angle and change in joint angle are related to the torque at a joint, the distortion of the motion at the joints clearly demonstrates that control of the hind limb during this postural task was non-linearly related to the sinusoidal input.II-2 J. M. BROOKHART AND R. E. TALBOTT 5. The uniformity of the response parameters, as assessed from the Fourier coefficients, indicated that all of the tested dogs adopted the same or nearly the same strategy for solving the problem of adjusting their postural control in response to the perturbation. Therefore, a reasonable hypothesis for future testing is that the central programme which generates this particular postural response will be structured similarly from one dog to the next.

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Section: Discussionmentioning

confidence: 82%