Cortico‐spinal tract of the cat. An attempt to correlate the pattern of degeneration with deficits in reflex activity following neocortical lesions

Chambers, W. W.; Liu, Chan-Nao

doi:10.1002/cne.901080103

Cited by 179 publications

(31 citation statements)

References 29 publications

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“…Although in the cat 'simple' locomotion on flat ground devoid of obstacles is only transiently impaired by motor cortical ablation the ability to execute more demanding locomotor tasks is nevertheless much reduced (Magoun & Ranson, 1938;Chambers & Liu, 1957;Adkins, Cegnar & Rafuse, 1971). Similar findings have been reported when the medullary pyramids were surgically interrupted: Liddell & Phillips (1944) showed that after unilateral or bilateral lesions cats rapidly resumed overground walking but when required to walk along a narrow elevated pole or a horizontal ladder they persistently became 'helplessly immobile'.…”

Section: Introductionsupporting

confidence: 69%

Changes in the discharge patterns of cat motor cortex neurones during unexpected perturbations of on‐going locomotion.

Marple‐Horvat

Amos

Armstrong

et al. 1993

The Journal of Physiology

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SUMMARY1. The impulse activity of single neurones in the forelimb part of the motor cortex was recorded extracellularly in unrestrained cats during self-paced locomotion on a horizontal circular ladder.2. Fifty-one cells (forty-nine of which discharged rhythmically in time with the step cycle) were recorded during encounters with a number of rungs that could be locked firmly in position or, alternatively, held in position by weak springs so that when stepped on they unexpectedly descended (under the weight of the animal) from 1 to 5 cm before contacting a mechanical stop.3. In eleven cells (22 %) including four fast-axon pyramidal tract neurones (PTNs), an increase in discharge occurred when the contralateral forelimb descended unexpectedly. Onset latency relative to the start of rung movement ranged from ca 20 to ca 100 ms. In eight cells latency was such that most of the response preceded contact of the rung with the stop; averaged over a number of trials the altered discharge in five of these cells (including two PTNs) represented an accurate profile of the averaged velocity of rung (and foot) descent. The three remaining cells appeared to be responding largely to the cessation of rung movement.4. Thirty-six of the cells were also studied during unexpected descent of the ipsilateral forelimb and six (17 %) displayed an increase in discharge (onset latency ca 35 to ca 80 ms); three of these were among those that also responded to contralateral descents.5. These findings for skilled locomotion requiring a high degree of visuomotor coordination are discussed and it is concluded that the motor cortex is rapidly informed regarding unexpected perturbations delivered to the contralateral forelimb at the onset of stance and that changes are evoked in the pattern of impulse traffic descending via the pyramidal tract.MS 9872

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Section: Introductionsupporting

confidence: 69%

Changes in the discharge patterns of cat motor cortex neurones during unexpected perturbations of on‐going locomotion.

Marple‐Horvat

Amos

Armstrong

et al. 1993

The Journal of Physiology

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“…It was demonstrated that simple locomotion does not require participation of the motor cortex or VL while complex locomotion does (Trendelenburg 1911; Chambers and Liu 1957; Liddell and Phillips 1944; Beloozerova and Sirota 1993a, b; Beloozerova and Sirota 1998). Regarding the motor cortex, we have previously suggested that the locomotion-related modulation of the activity of its neurons during simple locomotion has an informational character (Beloozerova and Sirota 1993a).…”

Section: Discussionmentioning

confidence: 99%

Differential Gating of Thalamocortical Signals by Reticular Nucleus of Thalamus during Locomotion

2012

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SUMMARY The thalamic reticular nucleus (RE) provides inhibition to the dorsal thalamus, and forms a crucial interface between thalamo-cortical and cortico-thalamic signals. Whereas there has been significant interest in the role of the RE in organizing thalamo-cortical signaling, information on the activity of the RE in the awake animal is scant. Here we investigated the activity of neurons within the ‘motor’ compartment of the RE in the awake, unrestrained cat during simple locomotion on a flat surface and complex locomotion along a horizontal ladder that required visual control of stepping. The activity of 88% of neurons in this region was modulated during locomotion. Neurons with receptive fields on the shoulder were located dorsally in the nucleus and had regular discharges; during locomotion they had relatively low activity and modest magnitudes of stride-related modulation, and their group activity was distributed over the stride. In contrast, neurons with receptive fields on the wrist/paw were located more ventrally, often discharged sleep-type bursts during locomotion, were very active and profoundly modulated, and their group activity was concentrated in the swing and end of stance. 75% of RE neurons had different activity during the two locomotion tasks. We conclude that during locomotion the RE differentially gates thalamo-cortical signals transmitted during different phases of the stride, in relation to different parts of the limb, and the type of locomotion task.

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“…Moreover, the timing of peak population output from forelimb motor cortex may differ between treadmill and ladder walking (see Armstrong & Marple-Horvat, 1996). Furthermore, walking over a flat surface devoid of obstacles is only transiently impaired by pyramidotomy or motor cortex lesion while, by contrast, more demanding forms of walking (including ladder walking) are grossly impaired for long periods (Liddell & Phillips, 1944;Chambers & Liu, 1957;Hicks & D'Amato, 1975). In the light of this background, we earlier studied the responses of motor cortical neurones during ladder walking to peripheral input resulting from a footfall onto a rung that proved unexpectedly unstable (Marple-Horvat et al 1993).…”

mentioning

confidence: 99%

Central regulation of motor cortex neuronal responses to forelimb nerve inputs during precision walking in the cat

Marple‐Horvat

Armstrong

1999

The Journal of Physiology

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To understand the role(s) in movement control of any pathway that forwards information from receptors in the limbs to some part of the central nervous system, information must be obtained regarding the extent to which, during active movement, its ability to transmit is subject to regulation (modulation; sometimes termed gating) by central mechanisms. Moreover, the possibility must be explored that such mechanisms may vary their influence with the type of movement or with its phases (for a detailed review, see Prochazka, 1989). Thus, to consider only the context of locomotor movements, the responsiveness of spinal reflex paths to inputs from both muscle and skin receptors is now known to differ between the presence and absence of stepping movements and to

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Cortico‐spinal tract of the cat. An attempt to correlate the pattern of degeneration with deficits in reflex activity following neocortical lesions

Cited by 179 publications

References 29 publications

Changes in the discharge patterns of cat motor cortex neurones during unexpected perturbations of on‐going locomotion.

Changes in the discharge patterns of cat motor cortex neurones during unexpected perturbations of on‐going locomotion.

Differential Gating of Thalamocortical Signals by Reticular Nucleus of Thalamus during Locomotion

Central regulation of motor cortex neuronal responses to forelimb nerve inputs during precision walking in the cat

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