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PubMed1978

Dependence of the activity of interpositus and red nucleus neurons on sensory input data generated by movement.

Cats performed flexion movements of the forearm, and the discharge of interpositus and red nucleus neurons was examined for relationships to the motion and to the EMG activity of agonist and antagonist muscles. It is shown that, over a wide range in the time course of the motion, the activity of the neurons is covariant with both the EMG and the movement parameters, in particular, the velocity. Also, the discharge of the interpositus neurons is modulated in phase with the velocity of passive movement. It is concluded that during fast, intentional movements, sensory input data generated by motion is a major determinant of the output of the interpositus nucleus. Furthermore, the results are consistent with the concept that this output provides a continuous modulation of spinal segmental mechanisms by way of the red nucleus and rubrospinal tract.

Animals↗
PubMedDate not supplied

Description of a large projection from the mesodiencephalic junction to the rostral red nucleus. An anatomical study in the rat and in the cat.

Horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP (WGA-HRP) were deposited in the rostral pole (Rpc) of the red nucleus in 6 rats and 5 cats. In the rat, a zone of dense retrograde cell labeling and of diffuse axonal labeling occurred in the sub-pretectal area, a region which corresponds to the posterior thalamic nucleus (PT) of Bold et al. (Brain Research, 12 (1984) 521-527). In the cat, a similar retrograde and anterograde pattern of labeling was observed. The labeled area extended from the deep pretectum up to the diencephalon above the dorsomedial aspect of the ventral posterior thalamic nucleus. In a second set of experiments, 14 rats received a tracer injection (HRP, WGA-HRP or Phaseolus vulgaris-leucoagglutinin) in the sub-pretectal area. The resultant pattern of labeling consisted in a heavy anterograde terminal labeling within the Rpc of the red nucleus. Sparse retrograde cell labeling also occurred in the Rpc.

Animals↗
PubMed1990

Spatio-temporal organization of the somaesthetic projections in the red nucleus transmitted through the spino-rubral pathway in the cat.

Although it has been known for a long time that in awake cats, natural stimulation of the skin induces short latency responses in rubrospinal cells, the pathway possibly involved has been identified only recently (Padel et al. 1988). This tract, which was described in acute, chloralose anaesthetized cats, ascends in the ventromedial spinal cord and is activated via collaterals of primary afferent fibres running in the dorsal columns of the spinal cord. The present study demonstrates that this newly described spino-rubral tract is able to send detailed somaesthetic information to the red nucleus. After lesions leaving intact only the spino-rubral pathway, excitatory and inhibitory responses to natural peripheral stimulations were recorded in identified rubral efferent cells. The most effective stimuli were touching the skin, passive joint rotation and hair displacement. Each cell was found to possess a particular receptive field. These fields which could be ipsi-, contra-, or bi-lateral were generally located on a single limb, although they could include two or more limbs, or even exceptionally the whole body with or without preferential zones. The topographic organization of receptive fields was arranged somatotopically in the red nucleus and overlapped the motor representation. The somaesthetic inputs transmitted through the spino-rubral pathway to the red nucleus are very similar to those previously observed in the intact cat, which supports the idea that this pathway may play a functional role in motor control. The spino-rubro-spinal loop may provide a fast adaptation of the descending motor command, thus producing a fine and harmonious tuning between the changing surroundings and the animal's movements.

Action Potentials↗
PubMed1984

Calcium-dependent potentials in mammalian red nucleus neurons in vitro.

Intracellular recordings were made from red nucleus (RN) neurons in guinea-pig slice preparations. The slow afterhyperpolarization (AHP) following an action potential was reversibly abolished by Co2+ or Mn2+. Its amplitude was dependent on the extracellular K+ concentration. When tetraethylammonium was added to the perfusing solution, a tetrodotoxin-resistant regenerative depolarization was evoked which was blocked by Co2+ or Mn2+. There results suggest that the slow AHP is produced by an increase in Ca2+-dependent K+ conductance and that RN neurons have a voltage-dependent Ca2+ conductance.

Action Potentials↗
PubMed2006

Effect of orofacial motor cortex stimulation on neuronal activity in the red nucleus.

We studied modulation of the activities of the red nucleus (RN) neurons under to electrical stimulation of the orofacial motor cortex (OfM) in urethane-anesthetized rats. Of 57 neurons studied, 30 (53%) neurons modulated the firing patterns. The firing patterns of the RN neurons were classified into four types: an excitation (E) type (n=4), a long inhibition (LI) type (n=4), a short inhibition (SI) type (n=22), and a no-effect type (n=27). These modulated neurons were intermingled in the dorso-ventral part of the RN. Our results suggest that the RN neurons receive excitatory or inhibitory inputs from the OfM.

Animals↗
PubMed1985

Ionic conductance associated with electrical activity of guinea-pig red nucleus neurones in vitro.

Intracellular recordings were made from red nucleus (r.n.) neurones in guinea-pig slice preparations in vitro. In the control solution, a fast action potential was elicited by a depolarizing current pulse. This fast action potential was abolished by tetrodotoxin (TTX). When tetraethylammonium (TEA) was added to the perfusing solution, a TTX-resistant slow action potential was elicited by a large depolarizing current pulse. This TTX-resistant slow action potential was abolished by Co2+ or Mn2+. In the control solution, the action potential was followed by a fast and a slow after-hyperpolarization (a.h.p.). The fast a.h.p. was abolished by TEA. The amplitude of the fast a.h.p. was dependent on the extracellular K+ concentration. The slow a.h.p. was reversibly abolished by Co2+ or Mn2+. The reversal potential of the slow a.h.p. was dependent on the extracellular K+ concentration. When the membrane potential was hyperpolarized, a time-dependent inward rectification was observed. This inward rectification was inhibited by Cs+ but not by Ba2+, TTX, TEA or Co2+. It is concluded that the fast action potential is produced by a voltage-dependent Na+ conductance, the TTX-resistant slow action potential is produced by a voltage-dependent Ca2+ conductance, the fast a.h.p. is produced by a voltage-dependent K+ conductance, the slow a.h.p. is produced by a Ca2+-activated K+ conductance and the inward rectification is produced by a time-dependent inward rectifier in r.n. neurones.

Action Potentials↗
PubMedDate not supplied

A special role of the parvocellular red nucleus in lesion-induced spontaneous tremor in monkeys.

The neural mechanisms underlying spontaneous tremor were investigated in monkeys. Tremor-producing ventromedial tegmental (VMT) lesions involve at least three major neural elements. (1) Parvocellular division of the red nucleus (RNpc); (2) cerebellothalamic fibers passing through the red nucleus, and, (3) nigrostriatal fibers. These three elements were destroyed stereotaxically in areas remote from the VMT area separately and/or in various combinations, and correlation between the site of lesions and tremor was made. Lesion-induced tremor appeared only when the three elements were destroyed. A possible, particular role of the RNpc in the production of the spontaneous tremor is discussed.

Animals↗
PubMed1981

Inferior red nucleus syndrome (Benedikt's syndrome) due to a single intramesencephalic metastasis from a prostatic carcinoma. Case report.

The authors describe a case of inferior red nucleus syndrome due to a solitary intramesencephalic metastasis from a glandular epithelioma of the prostate. They emphasize the rarity of cerebral metastases of prostatic origin, particularly at the level of the brain stem, and the exceptional features of a red nucleus syndrome originating from a tumour.

Brain Neoplasms↗
PubMed1987

The N-CAM D2-protein as marker for synaptic remodelling in the red nucleus.

We have followed the time-course of changes in the concentration of 3 neuronal and one glial antigen in the red nucleus in rats after unilateral lesion of the cerebellorubral connections. The neuronal markers were the neuronal cell adhesion molecule (N-CAM) D2-protein which is prevalent in newly formed neuronal membranes, and the D1- and D3-proteins, which are found mainly in mature neuronal membranes. The glial marker was S-100, a cytoplasmic protein. Six days after the lesion no changes in the concentration of the markers were found in the partially deafferentiated red nucleus. However, 10 days after the lesion the D2-protein concentration was significantly increased, in contrast to the D1-protein concentration which was decreased. After a further 3 days the D2-protein concentration began to decrease, approaching the still significantly decreased D1-protein concentration. Twenty-one days after the lesion the marker protein concentrations were not significantly changed from normal. However, whereas the concentrations of neuronal membrane markers were lower, the glial S-100 concentration showed a tendency to increase. Furthermore, although the changes in D3-protein concentration were unable to reach statistical significance alone they always followed the direction of D1-protein and were significantly in variance with the changes in D2-protein and S-100 concentrations. Our results support the notion of the N-CAM D2-protein as a useful marker for synaptic turnover in adult brain.

Animals↗
PubMed1985

Relation between red nucleus discharge and movement parameters in trained macaque monkeys.

Correlation and regression analyses were performed on thirty-three of the magnocellular red nucleus cells described in the previous paper. We sought to test for reliable relations between the parameters of individual tracking movements and corresponding bursts of neural discharge. High correlations were found between the following burst and movement parameters: (i) burst latency versus movement latency; (ii) burst duration versus movement duration; (iii) burst frequency versus movement velocity and (iv) number of spikes in the burst versus movement amplitude. Cells were ranked according to the average of the duration, velocity and amplitude correlation coefficients. The top twenty cells had average correlation coefficients ranging from 0.69 to 0.88 for their preferred movement. These cases were judged most likely to reveal the control functions of the red nucleus, and the following points refer to this sample. Burst onset led movement onset by 118 +/- 23 ms, and burst offset led movement offset by 50 +/- 38 ms. Burst duration increased as the duration of the movement increased (r = 0.87 +/- 0.11). The duration of the burst was approximately equal to movement duration (slope of 0.99 +/- 0.16) plus a constant (72 +/- 34 ms) throughout a broad range. Average discharge rate during the burst increased with average movement velocity (r = 0.69 +/- 0.15). The slope of the relation was 0.36 +/- 0.21 (pulses/s)/(deg/s) of joint rotation. The regression lines had consistent upward offsets (56 +/- 15 pulses/s) that exceeded the spontaneous discharge rate (17 +/- 10 pulses/s). The number of spikes in the burst increased with movement amplitude independent of velocity (r = 0.72 +/- 0.11). The slope of the relation was 0.62 spikes/deg and the offset was 13 +/- 4 spikes. The preferred movement was co-ordinated hand in fifteen cases, digit in three, elbow in one and shoulder in one. When these cells were tested with an alternate movement, the failure rate (cases in which a burst did not accompany a movement) increased from 1.4 to 20%, and the correlation coefficients generally were low and lacked significance. Cells in the top twenty had directionally specific responses, low variance in lead time, large depths of modulation (41-118 pulses/s) and low failure rates. Cells that failed to show strong parametric correlations often had one or more of the former attributes. It appears that high parametric correlations with individual movements are particularly restrictive criteria of relatedness.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1990

Inhibition of sensory responses of cat inferior olive neurons produced by stimulation of red nucleus.

1. The sensory responsiveness of cells in the inferior olive is known to be suppressed during certain phases of active movement. These experiments were designed to test the possibility that activity in the rubrospinal pathway contributes to this suppression. We recorded from cells sensitive to light touch located in one of the divisions of the inferior olive, the rostral dorsal accessory olive (rDAO), in cats anesthetized with pentobarbitol sodium. Responsiveness to peripheral stimuli was tested during and after trains of conditioning stimuli delivered to the rubrospinal pathway. 2. All 44 cells in our sample of rDAO neurons showed an inhibition of responsiveness to peripheral stimuli after conditioning stimulation of the rubrospinal pathway. Typical conditioning trains consisted of 0.2-ms pulses at 200 Hz for 100 ms. The mean current required for a reduction in firing probability to 0.5 was 31 microA. Slight increases in intensity often completely inhibited responses to peripheral stimuli. 3. Inhibition of responsiveness showed a delayed time course. Peak inhibition occurred approximately 50 ms after the last pulse in the conditioning train. In many cases there was no demonstrable inhibition during the conditioning train. Increases of train frequency, train duration, or stimulus intensity produced stronger and broader periods of olivary inhibition. 4. The lowest threshold points for eliciting rDAO inhibition coincided with either the magnocellular red nucleus (RNm) or the rubrospinal tract (RST). Stimulation at RST sites produced inhibition of responses in the contralateral but not in the ipsilateral rDAO. Transection of the RST in the upper brain stem blocked the inhibition produced by red-nucleus stimulation without altering the inhibition produced by tract stimulation caudal to the transection. The inhibitory effects thus appear to be caused by activation of the rubrospinal pathway. 5. The inhibitory timing observed in this study may be appropriate for explaining the suppression of olivary responsiveness to contact that has been observed in awake animals. Bursts of movement-related, red nucleus discharge often cease approximately 50 ms before the end of movement. This timing would allow peak inhibition to develop at approximately the time of contact with an object at the end of a goal-directed limb movement.

Animals↗
PubMed2002

Functional specialization within the cat red nucleus.

Magnocellular (RNm) and parvicellular (RNp) divisions of the cat red nucleus (RN) project to the cervical spinal cord. RNp projects more heavily to upper cervical levels and RNm projects more heavily to lower levels. The cells in RN are active during reaching and grasping, and the differences in termination suggest that the divisions influence different musculature during this behavior. However, the spinal termination may not reflect function because most rubrospinal terminations are to interneuronal regions, which can influence motor neurons at other spinal levels. To test for functional differences between RNm and RNp, we selectively stimulated RNm and RNp as well as the efferent fibers from each region. Electromyographic activity was recorded from seven muscles of the cat forelimb during reaching. The activity from each muscle was averaged over several thousand stimuli to detect influences of stimulation on muscle activity. Stimulation within the RN produced a characteristic pattern of poststimulus effects. The digit dorsiflexor, extensor digitorum communis (edc), was most likely to show facilitation, and several other muscles showed suppression. The pattern of activation did not differ between RNm and RNp. In contrast, stimulation of RNp fibers favored facilitation of shoulder muscles (spinodeltoideus and supraspinatus), and stimulation of RNm fibers favored facilitation of digit and wrist muscles (edc, palmaris longus, and extensor carpi ulnaris). Fiber stimulation produced few instances of poststimulus suppression. The results from fiber stimulation indicate that the physiological actions of RNm and RNp match their levels of spinal termination. The complex pattern of facilitation and suppression seen with RN stimulation may reflect synaptic actions within the nucleus.

Animals↗
PubMedDate not supplied

Synaptic responses of neurons in the parietal associative cortex of the cat to stimulation of the red nucleus.

Acute experiments on anesthetized and immobilized cats using intracellular recording were used to study the responses of neurons in the parietal associative cortex to stimulation of the red nucleus. Efferent neurons of the parietal cortex were identified by antidromal activation on stimulation of the intrinsic nuclei of the pons and motor cortex. Oligo- and polysynaptic EPSP in response to stimulation of the red nucleus were seen. The results are discussed in the light of the morphological organization of the rubrothalamic and cerebellothalamocortical tracts.

Action Potentials↗
PubMed1977

[Excitability of the senso-motor cortex and red nucleus of rabbits with different levels of cortical potential spatial synchronization].

The motor reaction of the rabbit to the threshold electrical stimulation of the sensomotor cortex and red nucleus was studied to determine excitability of these structures. Under conditions of the computer-controlled experiment the excitability of the two structures was compardd for situations characterized by different levels of cortical potential correlation. An increase in the spatial synchronization of the cortical potentials is shown to be accompanied by intensification in excitability of the sensomotor cortex and red nucleus. This intensification seems to be one of possible neurophysiological mechanisms of the probability increase for the effector reaction to sensory stimuli when the cortical spatial synchronization rises.

Animals↗
PubMed2006

Modulation of cortically induced rhythmical jaw movements by stimulation of the red nucleus in the rat.

We study whether stimulation of the red nucleus (RN) can modulate rhythmical jaw movements in rats anesthetized by urethane. Rhythmical jaw movements were induced by repetitive electrical stimulation of the two cortical masticatory areas (area A: the orofacial motor cortex; area P: the insular cortex). Stimuli applied to the RN did influence rhythmical jaw movements induced by stimulation of the A-area. Stimuli applied in the jaw-closing phase increased the amplitude of the jaw-closing movement. Stimuli applied in the jaw-opening phase disturbed the rhythm of jaw movements and induced a small jaw-closing movement. Stimuli applied to the RN did not influence rhythmical jaw movements induced by stimulation of the P-area. These results indicate that the RN is involved in the modulation of rhythmical jaw movements induced by stimulation of the A-area.

Animals↗
PubMed1994

A Golgi study on the red nucleus in man.

The different cell types comprising the human red nucleus (RN) from eight patients without neuronal diseases were investigated using the Golgi-Braitenberg method for long-stored autopsy material. No giant cells were found due to regression of the magnicellular part of the human RN. We found larger (40-50 microns) and smaller (30 microns perikaryon size) medium-sized multipolar neurons with long dendrites, mushroom spines and typical distal dendritic tufts. The larger medium-sized RN neurons had some brush-shaped dendritic end portions which could not be observed in the Golgi studies on various other mammals described in the literature. We additionally found small neurons with a perikaryon size of 15 microns. These cells were thought to be intrinsic neurons similar to those in animal investigations. The neuronal types found in the normal human RN corresponded to those in the parvicellular part of the mammalian RN. Dendritic end brushes, however, are typical only for the human RN.

Aged↗
PubMedDate not supplied

Electrophysiological identification of a somaesthetic pathway to the red nucleus.

In awake chronically implanted cat, the cells in the red nucleus (RN) can be either activated or inhibited by natural stimulation on periphery. The effective stimuli are touching the fur, rotating the joints and tapping the muscles. A somaesthetic map has been constructed with the face area dorsally, the forelimb more ventrally and the hindlimb lateroventrally in the RN. In acute preparations, after ablation of the motor cortex and the cerebellum and section of the dorsal columns of the spinal cord at cervical level, the RN cells were still reacting to natural stimulation of the skin or electrical stimulation of peripheral nerves. The course of the somaesthetic pathway was systematically mapped by microstimulation of the spinal cord. It was shown that it follows the primary afferents which enter the dorsal columns, where they give off collaterals which relay at segment levels. After decussation the fibres ascend the ventromedial quadrant of the cord. A large portion of the fibres relay a second time in the medulla. The existence of such a pathway can account for the somaesthetic responses recorded in the RN in awake cats.

Afferent Pathways↗