Setting and resetting of level of postural muscle tone in decerebrate cat by stimulation of brain stem.

Mori, Shigemi; Kikuchi, Kôichi; Sakamoto, Takashi; Aoki, Mamoru; Tomiyama, Tomotaka

doi:10.1152/jn.1982.48.3.737

Cited by 104 publications

(39 citation statements)

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“…The locomotion produced by stimulation of the MRF and PLS was often preceded by increased extensor tonus of the limbs, whereas stimulation of areas l-2 mm dorsal to the effective MRF sites often decreased extensor tonus as described by Mori et al (1982). Extensor tonus was not evaluated systematically in the present study, however.…”

Section: Electrically Induced Locomotionmentioning

confidence: 62%

“…This has been suggested to explain the effects of ventral tegmental field stimulation described by coworkers (1978, 1980) which produces increased hindlimb extensor activity and locomotion when electrically stimulated. Postural adjustments prior to the onset of locomotion have previously been reported during stimulation of the MLR (Mori et al, 1980;Garcia-Rill et al, 1985) and its reticular formation projection sites (Mori et al, 1978(Mori et al, , 1980(Mori et al, , 1982. Thus, while the MLR relays its descending command signal for locomotion, it may also influence parallel postural systems also located in the MRF.…”

Section: Mlr-reticulospinal Pathwaymentioning

confidence: 87%

“…A locomotor somatotopic organization within the MRF is supported by observations that some reticulospinal neurons only project to cervical spinal cord levels (Peterson et al, 1975) and that the firing patterns of reticulospinal cells may be linked to the activity of individual muscles from particular limbs during locomotion (Drew and Rossignol, 1984). Other factors such as the excitability levels of the brain stem and spinal cord may affect the ability of the brain stem to produce locomotion when stimulated (Mori et al, 1977(Mori et al, , 1982. How this affects the recruitment of individual limbs or muscles during controlled locomotion is unclear.…”

Section: Mlr-reticulospinal Pathwaymentioning

confidence: 97%

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Locomotion produced in mesencephalic cats by injections of putative transmitter substances and antagonists into the medial reticular formation and the pontomedullary locomotor strip

1988

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The purpose of this study was to determine the distribution of cells in the medial reticular formation (MRF) and the pontomedullary locomotor strip (PLS), which can induce locomotion when activated. Controlled microinjections of neuroactive substances (Goodchild et al., 1982) into the MRF or PLS were made in order to activate cell bodies in those areas. The ability of trigeminal receptive field stimulation to induce locomotion before and after drug infusion into the PLS was also assessed since the PLS and the spinal nucleus of the trigeminal nerve are similar in their anatomical distribution. Experiments were performed on precollicular-postmamillary decerebrate cats walking on a treadmill. Injections of glutamic acid (GA; 500 nmol) into the MRF produced locomotion that was antagonized by infusion of glutamic acid diethyl ester into the same spot. Decreases in the current threshold for locomotion produced by electrical stimulation of the MRF were observed when the MRF was infused with either GA (40–80 nmol), DL- homocysteic acid (DL-HCA; 200 nmol), or picrotoxin (PIC; 15 nmol). Injections of GA (100 nmol), DL-HCA (700 nmol), PIC (10–50 nmol), and substance P (2 nmol) into the PLS also produced locomotion. Locomotion produced by injections of PIC into the PLS was blocked by infusion of equal amounts of muscimol or GABA. Effective PLS injection sites were all confined to the trigeminal spinal nucleus or immediately ventral and medial to this in the adjacent lateral reticular formation. Trigeminal nerve peripheral field stimulation evoked locomotion after microinjection of PIC into the PLS, although this same facial stimulus was not effective prior to drug injection. We conclude that the MRF and PLS regions of the cat brain stem contain cells that produce locomotion when chemically stimulated, and we suggest that the PLS is closely related to or synonymous with the spinal nucleus of the trigeminal nerve. Furthermore, we suggest that stimulation of trigeminal afferents is analogous to stimulation of segmental afferent pathways in the production of locomotion (Sherrington, 1910; Jankowska et al., 1967; Afelt, 1970; Budakova, 1972; Grillner and Zangger, 1979).

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Section: Electrically Induced Locomotionmentioning

confidence: 62%

Section: Mlr-reticulospinal Pathwaymentioning

confidence: 87%

Section: Mlr-reticulospinal Pathwaymentioning

confidence: 97%

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Locomotion produced in mesencephalic cats by injections of putative transmitter substances and antagonists into the medial reticular formation and the pontomedullary locomotor strip

1988

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“…Presence of weak EMG responses to tilts and pushes, with the temporal pattern similar to that in control, supports the second hypothesis. To test these hypotheses, in the present study we stimulated tonically two brainstem areas, which are known to affect the postural system, the MLR and VTF [10,25,26], and examined postural performance by applying lateral tilts and lateral pushes to the posterior part of the body. It was found that MLR stimulation, during the period preceding the onset of locomotion, caused an increase of the extensor muscle tone, as well as an augmentation of the EMG responses to tilts and pushes.…”

Section: Activation Of Postural Mechanisms In Postmammillary Rabbitsmentioning

confidence: 99%

“…An increase of the extensor tone in decerebrated animals can be caused by stimulation of the ventral tegmental field (VTF) in the medial brainstem [26]. The third specific aim of this study was to examine the effect of VTF stimulation on muscle tone and on the capacity to perform postural corrections in the postmammillary rabbits.…”

Section: Introductionmentioning

confidence: 99%

Postural performance in decerebrated rabbit

Musienko

Zelenin

Lyalka

et al. 2008

Behavioural Brain Research

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It is known that animals decerebrated at the premammillary level are capable of standing and walking without losing balance, in contrast to postmammillary ones which do not exhibit such behavior. The main goals of the present study were, first, to characterize the postural performance in premammillary rabbits, and, second, to activate the postural system in postmammillary ones by brainstem stimulation. For evaluation of postural capacity of decerebrated rabbits, motor and EMG responses to lateral tilts of the supporting platform and to lateral pushes were recorded before and after decerebration. In addition, the righting behavior (i.e., standing up from the lying position) was video recorded.We found that, in premammillary rabbits, responses to lateral tilts and pushes were similar to those observed in intact ones, but the magnitude of responses was reduced. During righting, premammillary rabbits assumed the normal position slower than intact ones.To activate the postural system in postmammillary rabbits, we stimulated electrically two brainstem structures, the mesencephalic locomotor region (MLR) and the ventral tegmental field (VTF). The MLR stimulation (prior to elicitation of locomotion) and the VTF stimulation caused an increase of the tone of hindlimb extensors, and enhanced their responses to lateral tilts and to pushes.These results indicate that the basic mechanisms for maintenance of body posture and equilibrium during standing are present in decerebrated animals. They are active in the premammillary rabbits but need to be activated in the postmammillary ones.

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