Differential effects of lesions of the anterior and posterior sigmoid gyri in cats

Adkins, R J; Cegnar, Maureen R.; Rafuse, Donald D.

doi:10.1016/0006-8993(71)90092-8

Cited by 35 publications

(24 citation statements)

References 5 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: 70%

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: 70%

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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“…This pattern of differential 'accessibility' is in good correspondence with the fact that hypoflexion of the contralateral limbs is prominent among the behavioural deficits produced in cats by motor cortical lesions (e.g. Adkins, Cegnar & Rafuse, 1971) or by pyramidectomy (e.g. Liddell & Phillips, 1944).…”

Section: Emgs Evoked From Motor Cortex Effect Of Pyramidectomysupporting

confidence: 60%

“…What the precise significance of a dual organization may be for movement control has yet to be determined, but it has been reported that ablations of the anterior and posterior sigmoid gyri produce different patterns of motor deficit in the cat (Adkins et al 1971). Vicario et al (1983) have suggested that the rostral area may be involved in movement initiation while the caudal part utilizes specific somatosensory inputs to achieve regulation of ongoing movements.…”

Section: Response Latenciesmentioning

confidence: 99%

Electromyographic responses evoked in muscles of the forelimb by intracortical stimulation in the cat.

Armstrong¹,

Drew²

1985

The Journal of Physiology

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SUMMARY1. Chronically implanted microwires were used to deliver brief trains of electrical stimuli (11 cathodal pulses at 330 Hz and intensity 5-35,A) to sixty-two locations in the grey matter of the pericruciate cortex in cats.2. Electromyographic (e.m.g.) responses in the contralateral forelimb were recorded from a total of ten muscles (four to eight in each animal) acting about the shoulder, elbow and wrist and on the digits. The animals were relaxed with little background e.m.g. in the muscles and as a result only excitatory effects could be described.3. Five muscles which are flexors in the locomotor context were excited from more electrodes, distributed more widely across the motor cortex, than another five muscles which are extensors during locomotion; this difference in 'accessibility' was present both at 35 ,uA stimulus intensity and at 15 1iA.4. At a stimulus intensity of 15 ,uA, effective cortical electrodes tended to cluster either in the most lateral part of the anterior sigmoid gyrus (rostromedial focus) or in the coronal gyrus just caudal to a line prolonged beyond the lateral end of the cruciate sulcus (caudolateral focus). This is consistent with the existence of a double motor representation within the forelimb motor cortex (Pappas & Strick, 1981). 5. The two foci were similar in that both gave rise to more flexor than extensor responses and to fewer responses in digit or wrist muscles than in muscles acting about more proximal joints (elbow and shoulder).6. At stimulus intensity 35 #uA the latency of the earliest e.m.g. responses ranged from 11 to 14 ms in different muscles.7. For some muscles and electrodes the amplitude of the e.m.g. responses was substantially altered by a quite small postural change.8. After pyramidectomy the cortical thresholds and the e.m.g. latencies were both greatly increased.

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“…However, a number of studies have pointed out differences in the connections and functions of rostral and caudal subdivisions of area 4g, separated by the cruciate sulcus (Adkins et al, 1971;Vicario et al, 1983;Yumiya and Ghez, 1984). Because, in other carnivores, the SMA has been tentatively identified in the anterior sigmoid gyrus Jameson et al, 1968;Gorska, 1974), SMA may also be located in the anterior sigmoid gyrus of the cat.…”

Section: Motor Areas In the Catmentioning

confidence: 92%

“…Secondly, separate representations of the forelimb and hindlimb in r4g and c4g are suggested by the study of Groos et al (1978). Thirdly it has been shown that rostral and caudal 4g have different cortical connections and functional specializations (Adkins et al, 1971;Vicario et al, 1983;Yumiya and Ghez, 1984). Finally, cortical mapping studies in dogs and racoons suggest that there may be separate representations of contralateral body parts in the anterior and posterior sigmoid gyri Jameson et al, 1968;Gorska, 1974).…”

Section: Electrical Stimulation Of the Motor Cortexmentioning

confidence: 93%

Identification of motor areas of the cat cerebral cortex based on studies of cortical stimulation and corticospinal connections

Ghosh

1997

J. Comp. Neurol.

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The location and topography of motor areas in the cat cerebral cortex were studied by electrical stimulation of the cortex in five animals, and by the injection of retrograde tracers into the spinal cord of four animals. Movements evoked by intracortical microstimulation (ICMS) of the anterior, posterior and lateral sigmoid gyri, both banks of the cruciate sulcus and the dorsal bank of the presylvian sulcus were observed in anaesthetized cats. Fluorescent tracers (Fast Blue and/or Diamadino Yellow) were injected into the lateral funiculus in the second cervical segment, into the gray matter of cervical segments C3-T1 and/or into the gray matter of lumbar segments L2-S1. Contraction of the contralateral forelimb, hindlimb or facial muscles was observed following electrical stimulation of several cytoarchitectonic areas: 4 gamma, 4 delta, 6a alpha, 6a gamma, and 3a. These findings suggested representations of contralateral forelimb and hindlimb movements in areas 4 gamma and 4 delta, and of the contralateral forelimb muscles in areas 6a alpha and 6a gamma. Corticospinal neurons were located in all the above cytoarchitectonic areas as well as in areas 3b, 1, 2, 2pri, and 5. Large numbers of neurons were labeled in areas 4 gamma and 4 delta, and moderate labeling was observed in areas 6a gamma and 6a alpha. Corticospinal neurons projecting to cervical and lumbar segments were located in areas 4 gamma and 4 delta, while those projecting only to cervical segments were detected in areas 6a alpha and 6a gamma. Based on these findings it is proposed that within the motor cortex of the cat there are representations of limb movements in several cytoarchitectonic subdivisions. Many of these representations may be candidate secondary motor areas.

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Differential effects of lesions of the anterior and posterior sigmoid gyri in cats

Cited by 35 publications

References 5 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.

Electromyographic responses evoked in muscles of the forelimb by intracortical stimulation in the cat.

Identification of motor areas of the cat cerebral cortex based on studies of cortical stimulation and corticospinal connections

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