Mechanisms mediating ipsilateral limb hyperflexion after cerebellar paravermal cortical ablation or cooling

Yü, Jen; Tarnecki, R; Chambers, W. W.; Liu, C.N.; Konorski, Jerzy

doi:10.1016/0014-4886(73)90015-0

Cited by 18 publications

(3 citation statements)

References 22 publications

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“…Levels of spontaneous activity in interpositus neurones under chloralose anaesthesia similar to those found here were described by Yu, Tarnecki, Chambers, Liu & Konorski (1973). They found many cells with relatively slow spontaneous activity, and a number of antidromically identified units which were silent.…”

Section: Spontaneous Activity Of Interpositus Neuronessupporting

confidence: 86%

Effects of afferent volleys from the limbs on the discharge patterns of interpositus neurones in cats anaesthetized with alpha‐chloralose.

Armstrong¹,

Cogdell²,

Harvey³

1975

The Journal of Physiology

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SUMMARY1. In cats anaesthetized with oc-chloralose, micro-electrodes have been used to record the discharge patterns of single neurones in the region of the nucleus interpositus.2. Almost all cells tested could be antidromically invaded following electrical stimulation of the contralateral red nucleus, showing that they were cerebellar efferent neurones.3. A little over half of the interpositus neurones were spontaneously active, usually at rates of less than 20 impulses/sec. 4. About 40 % of the cells had no spontaneous activity, although they gave brisk responses to electrical stimulation of cutaneous nerves. Such silent units were encountered most frequently in the earlier stages of an experiment, but a number were found more than 15 hr after the beginning of an experiment.5. Stimulation of cutaneous and mixed nerves of the fore and hind limbs provoked impulse discharges of the cells and also produced phases of deceleration of the resting discharge of spontaneously firing cells.6. The typical response of an interpositus neurone consisted of a short latency (6-35 msec) discharge, usually separated from a long latency (50-500 msec) discharge by a period of inhibition or return to the resting discharge rate. The two phases of excitation appeared to be independently generated, since in a number of cells one phase appeared without the other. In addition, the later phase of excitation was abolished in all cells tested by a small dose of pentobarbitone which produced very little effect on the earlier phase. The 9. The possibility that these long latency responses have a physiological significance in relation to locomotion is discussed.

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Section: Spontaneous Activity Of Interpositus Neuronessupporting

confidence: 86%

Effects of afferent volleys from the limbs on the discharge patterns of interpositus neurones in cats anaesthetized with alpha‐chloralose.

Armstrong¹,

Cogdell²,

Harvey³

1975

The Journal of Physiology

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“…The inactivation of the interposed nuclei downregulated the forelimb withdrawal response, and application of the chloride channel blocker picrotoxin upregulated this response. Related observations were made by Yu et al (1973). These authors found that activation of the interposed nuclei produced by cooling the intermediate cerebellar cortex in the cat caused forelimb hyperflexion.…”

Section: Intermediate Cerebellum and Flexion Movementsmentioning

confidence: 52%

Conditioned and unconditioned forelimb reflex systems in the cat: involvement of the intermediate cerebellum

Kolb¹,

Irwin

Bloedel

et al. 1997

Exp Brain Res

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Temporary inactivation of the cerebellar interposed nuclei was used to assess the role of the intermediate cerebellum in the performance of forelimb cutaneo-muscular reflexes in the cat. The following types of reflexive responses were evaluated: the classically conditioned and unconditioned forelimb withdrawal responses and the forelimb tactile placing, hopping and magnet responses. The experiments tested the hypothesis that the intermediate cerebellum is involved in the performance of all the above forelimb reflexes. The forelimb withdrawal reflex was classically conditioned in a newly developed paradigm in which animals were first operantly conditioned to stand on four elevated platforms. Trained animals were microinjected with a gamma-aminobutyric acid (GABA) agonist, muscimol, in the interposed nuclei, and the effects of inactivation of the intermediate cerebellar output on the forelimb reflexes were examined. The main findings of these experiments are that unilateral muscimol inactivation of the interposed nuclei in the cat abolished the expression of the classically conditioned limb flexion reflex, suppressed the performance of the unconditioned withdrawal reflex and, in parallel, down-regulated the tactile placing, hopping and magnet postural responses in the ipsilateral forelimb. These observations are inconsistent with concepts indicating exclusive involvement of the intermediate cerebellum in the classically conditioned reflexes elicited by aversive stimuli. On the contrary, they support the hypothesis of a more global involvement of this structure in learned and unlearned defensive flexion reflexes and in automatic postural response systems.

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“…If the overlying inhibitory Purkinje neurons (19) are removed, any input to the deep cerebellar nucleus normally modulated by the damaged cortex would have an exaggerated effect on cells to which the deep cerebellar nuclei project. Thus, damage to the midline vernal region results in extensor jerks because such neurons as those of the lateral vestibular nucleus, which primarily excite extensor mo$r neumns (28), are unchecked; and a paravermal lesion leads to flexor jerks because the red nucleus, which facilitates flexor motor neuronal activity, is powerfully driven by the released interpositus neurons (63). During wakefulness a sudden external stimulus will incite a flexion movement or an exaggerated extensor posture depending upon whether the lesion is in the paravermal or verrnal cortex (35,63).…”

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confidence: 99%

Relationships Between Phenomena of Paradoxical Sleep and their Counterparts in Wakefulness

Ar¹

1980

The Warsaw Colloquium on Instrumental Conditioning and Brain Research

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Abstract. Our studies suggest that para'doxical sleep is a state in which the brainstem is in a functional mode normally associated with presentations of novel stimuli. Furthermore, the combination of atonia and an internal state of activation indicates sustained activity of a brainstem mechanism designed to dampen responses to sudden, novel stimuli in wakefulness lest the animal over react and run blindly into danger prior to stimulus analysis. This con~lusi~on stems from two sets of data. Studies of large-amplitude waves, which characteristically occur spontaneously just prior to and during paradoxical sleep, have demonstrated that the waves are signs of alerting. These waves, termed ponto-geniculooccipital (PGO) spikes, can be induced during both slow wave and paradoxical sleep by extennal stimuli at a threshold below actual arousal. Whenever cats are confronted with novel stimuli during wakefulness, eye movement potentials, which are recorded from the same sites as PGO spikes but differ from them in several characteristics, assume all the characteristics of PGO spikes. These observations indicate that the central nervous system during paradoxical sleep is in a "peculiar" state of activation which is not behaviorally expressed. Other experiments have focused on the muscle atonia of paradoxical sleep. Small, bilateral dorsolateral pontine tegmental lesions create the dramatic phenomenon of paradoxical sleep without atonia which is characterized as follows: After slow wave sleep, when paradoxical sleep with muscle atonia would

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Mechanisms mediating ipsilateral limb hyperflexion after cerebellar paravermal cortical ablation or cooling

Cited by 18 publications

References 22 publications

Effects of afferent volleys from the limbs on the discharge patterns of interpositus neurones in cats anaesthetized with alpha‐chloralose.

Effects of afferent volleys from the limbs on the discharge patterns of interpositus neurones in cats anaesthetized with alpha‐chloralose.

Conditioned and unconditioned forelimb reflex systems in the cat: involvement of the intermediate cerebellum

Relationships Between Phenomena of Paradoxical Sleep and their Counterparts in Wakefulness

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