Spinal Projections of the Cat Parvicellular Red Nucleus

2002 ◽  
Vol 87 (1) ◽  
pp. 453-468 ◽  
Author(s):  
Milton Pong ◽  
Kris M. Horn ◽  
Alan R. Gibson
Keyword(s):  
Spinal Cord ◽  
Dentate Nucleus ◽  
Inferior Olive ◽  
Red Nucleus ◽  
Interpositus Nucleus ◽  
Limb Musculature ◽  
Caudal Portion ◽  
Cerebellar Interpositus Nucleus ◽  
Cerebellar Dentate Nucleus ◽  
Rostral Portion

Traditionally, the red nucleus of the cat is divided into two parts: a large-celled, magnocellular, division (RNm) and a small-celled, parvicellular, division (RNp). The RNm projects to the spinal cord and receives input from the cerebellar interpositus nucleus. The RNp projects to the inferior olive and receives input from the cerebellar dentate nucleus. In this report, we reexamine the connections of the red nucleus using the bidirectional tracer wheat germ agglutinin-horseradish peroxidase (WGA-HRP). Our findings demonstrate that the cat RNp has a large caudal and lateral region that projects to contralateral spinal cord and not to the inferior olive. The spinally projecting region of RNp receives input from the dentate nucleus and a lateral segment of anterior interpositus. Cervical projections from the red nucleus show a topography with the rostral portion of RNp favoring upper segments and the caudal portion of RNm favoring lower segments. The results show that dentate output can influence spinal activity without passing through the cerebral cortex. For the control of movements such as reaching and grasping, we suggest that RNp and dentate focus on the control of proximal limb musculature, whereas RNm and the anterior interpositus focus on the control of distal limb musculature. We also suggest that other species are likely to have a small-celled area of red nucleus projecting to the spinal cord.

Somatotopic studies on red nucleus: spinal projection level and respective receptive fields

1975 ◽  
Vol 38 (4) ◽  
pp. 965-980 ◽  
Author(s):  
J. C. Eccles ◽  
T. Rantucci ◽  
P. Scheid ◽  
H. Taborikova
Keyword(s):  
Spinal Cord ◽  
Red Nucleus ◽  
Receptive Fields ◽  
Anterior Lobe ◽  
Cervical Cord ◽  
Pars Intermedia ◽  
Interpositus Nucleus ◽  
Rubrospinal Tract ◽  
Testing Procedures ◽  
Axonal Projections

The somatotopic inputs into red nucleus (RN) neurons have been studied with special reference to their level of projection in the spinal cord. As inputs we employed either volleys in predominantly cutaneous nerves of forelimb and hindlimb or cutaneous mechanoreceptor discharges evoked by taps to footpads of forelimb and hindlimb. There has been physiological confirmation of the anatomical findings that RD neurons projecting to the lumbar cord are located in the ventrolateral zone of the pars magnocellularis, whereas in the dorsomedial zone are RN neurons with cervical but not lumbar projection. Somatotopically there was found to be a differentiation of input to RN neurons according as they projected to the lumbar or only to the cervical cord. This finding was presented in the form both of tables and of somatotopic maps. As expected, this discrimination was more restrictive for the more selective inputs from pad taps than for nerve inputs. Nevertheless, forelimb inputs often had a considerable excitatory and inhibitory action on lumbar-projecting RN neurons, and vice versa for cervical-projecting neurons. There were two notable somatotopic findings that suggest specificities of connectivities. First, despite the large convergence of IP neurons onto RN neurons (about 50-fold), the degree of somatotopic discrimination was about the same for interpositus and RN neurons with two testing procedures: between inputs from forelimb and hindlimb; and between inputs from pads on one foot. Second, although there was in the interpositus nucleus a considerable topographical admixture of neurons with dominant forelimb or hindlimb inputs, the axonal projections of these neurons were apparently unscrambled on the way to the target RN neurons, so as to deliver the somatotopic specificities observed for two classes of RN neurons; those projecting down the spinal cord beyond L2 level, and those projecting to C2 but not L2. Finally, there is a general discussion of motor control with reference to the pathway; pars intermedia of anterior lobe of cerebellum leads to interpositus nucleus leads to red nucleus leads to rubrospinal tract leads to spinal motoneurons.

Responses of red nucleus neurons to antidromic and synaptic activation

1975 ◽  
Vol 38 (4) ◽  
pp. 947-964 ◽  
Author(s):  
J. C. Eccles ◽  
P. Scheid ◽  
H. Taborikova
Keyword(s):  
Spinal Cord ◽  
Red Nucleus ◽  
Interpositus Nucleus ◽  
Rubrospinal Tract ◽  
Impulse Generation ◽  
Axonal Conduction ◽  
Antidromic Responses ◽  
Afferent Inputs ◽  
The Right ◽  
Good Agreement

An account is given of the responses of 432 red nucleus (RN) neurons with axons projecting down the spinal cord. Almost half were in an initial series of 18 experiments on anesthetized cats, and the remainder were in a second series of 12 experiments on decerebrate unanesthetized cats. The differences between the two series were of little significance. All recording was from single neurons using extracellular glass microelectrodes that were inserted throught the right superior colliculus and directed to the right red nucleus at a standard orientation. Identification of RN neurons was both by location, checked by subsequent histology, and by antidromic invasion from the spinal cord. The spinal stimulating electrodes were placed in proximity to the left rubrospinal tract at C2 and L2 segmental levels. Axonal conduction velocities were calculated from the latency differential between the L2 and C2 antidromic responses and were usually in the range 60-130 m/s, 97% of all neurons located in the red nucleus had axons projecting to the C2 level, and 37% projected to the L2 level. The responses of 229 RN neurons were observed with stimulation applied to the contralateral (left) interpositus nucleus. In 10 (5%) there were antidromic responses to both interpositus and C2 stimulation, a finding in good agreement with the anatomical description of rare axon collaterals from rubrospinal fibers to the interpositus nucleus. In 209 (91%), there was a clear monosynaptic excitation. The impulse generation was at a latency usually of 1.0-1.8 ms, which a modal value of 1.4 ms. The afferent inputs to RN neurons were provided by stimulation either of predominantly cutaneous nerves in all four limbs or of cutaneous mechanoreceptors of the contralateral forelimb and hindlimb...

scholarly journals Organization of Excitatory Inputs from the Cerebral Cortex to the Cerebellar Dentate Nucleus

1993 ◽  
Vol 20 (S3) ◽  
pp. S19-S28 ◽  
Author(s):  
Shinoda Yoshikazu ◽  
Sugiuchi Yuriko ◽  
Futami Takahiro
Keyword(s):  
Cerebral Cortex ◽  
Dentate Nucleus ◽  
Inferior Olive ◽  
Mossy Fibers ◽  
Excitatory Input ◽  
Control Mechanisms ◽  
Pontine Nucleus ◽  
Pericruciate Cortex ◽  
Cerebellar Dentate Nucleus ◽  
Stimulation Of

ABSTRACT:Intracellular recording was made from dentate nucleus neurons (DNNs) in anesthetized cats, to investigate cerebral inputs to DNNs and their responsible pathways. Stimulation of the medial portion of the contralateral pericruciate cortex most effectively produced EPSPs followed by long-lasting IPSPs in DNNs. Stimulation of the pontine nucleus (PN), the nucleus reticularis tegmenti pontis (NRTP) and the inferior olive (IO) produced monosynaptic EPSPs and polysynaptic IPSPs in DNNs. The results indicate that the excitatory input from the cerebral cortex to DNNs is at least partly relayed via the PN, the NRTP and the 10. Intraaxonal injection of HRP visualized the morphology of mossy fibers from the PN to the DN and the cerebellar cortex. The functional significance of the excitatory inputs from the PN and the NRTP to the DN is discussed in relation to the motor control mechanisms of the cerebellum.

Cerebellar Dentate Nucleus in Alzheimer’s Disease with Myoclonus

1999 ◽  
Vol 10 (2) ◽  
pp. 81-88 ◽  
Author(s):  
Yuken Fukutani ◽  
NigelJ. Cairns ◽  
IanP. Everall ◽  
Andrew Chadwick ◽  
Kiminori Isaki ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Dentate Nucleus ◽  
Cerebellar Dentate Nucleus

Red nucleus projections to distinct motor neuron pools in the rat spinal cord

2002 ◽  
Vol 448 (4) ◽  
pp. 349-359 ◽  
Author(s):  
Martin Küchler ◽  
Karim Fouad ◽  
Oliver Weinmann ◽  
Martin E. Schwab ◽  
Olivier Raineteau
Keyword(s):  
Spinal Cord ◽  
Motor Neuron ◽  
Red Nucleus ◽  
Rat Spinal Cord
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