The present findings of impaired trace eyeblink acquisition in patients with cortical cerebellar degeneration suggest that the cerebellar cortex in humans, in addition to the interposed nucleus, is involved in trace eyeblink conditioning, if the trace interval is relatively short. 
Effects of inactivating the IO on CR expression and on neuronal activity in the anterior cerebellar interposed nucleus (IN) were examined.
interposed nucleus likely contributes to movement performance.
In SCA patients with lesions including parts of the cerebellar interposed nucleus trace eyeblink conditioning was significantly impaired. Consistent with animal studies the findings of the present human lesion study suggest that, in addition to forebrain areas, the interposed nucleus is of importance in trace eyeblink conditioning.
However, there is evidence to show that the interposed nucleus contains respiratory-modulated neurons and is involved in coughing motor control..
Larsell lobule H VI and interposed nucleus) are commonly supplied by the SCA.
Labeled terminals were seen ipsilaterally in the ventrolateral part of the posterior interposed nucleus and the basal interstitial nucleus of the cerebellum at their rostral levels, and in the ventromedial part of the lateral cerebellar nucleus.
At 6 weeks postinfection, PrP(Sc) was detected in the lateral vestibular nucleus and the interposed nucleus of the cerebellum ipsilateral to the site of sciatic nerve inoculation and in the red nucleus contralateral to HY TME inoculation.
In RMN, many neurons exhibited definite alpha(1A) subunit-staining in the medial nucleus, interposed nucleus, and lateral nucleus of deep cerebellar nuclei.
We have examined the organisation of connections between the zona incerta (ZI), a small diencephalic nucleus deriving from the ventral thalamus, and the interposed nucleus (Int) of the cerebellum.
A mediolateral topography was noted in the projections from the rostral half of the medial accessory olive to the posterior interposed nucleus. The anterior interposed nucleus receives olivary afferents from the dorsal accessory olive. Its rostromedial parts are directed to the lateral part of the anterior interposed nucleus and its caudolateral part reach the medial anterior interposed nucleus.
A stimulating electrode was sequentially placed into the fastigial nucleus (FN), the interposed nucleus, and the lateral nucleus.
The medial part of the posterior interposed nucleus sends most projections to the caudomedial red nucleus, prerubral regions and parvicellular reticular formation, all contralateral to the injection site. The anterior interposed nucleus specifically targets the inferior olive, the red nucleus, the pontine reticulotegmental nucleus, the prectectum and the ventrolateral thalamic nucleus.
The CS was a weak electric shock applied on the interposed nucleus of the cerebellum in sites that initially elicited forelimb flexion (i.e., alpha motor responses) in three cats, and equal proportions of flexor and extensor responses in two cats.
Skilled movements, which in the cat are controlled by the C1, C3 and Y zones via the anterior interposed nucleus, may in the rat be partly controlled by the ax zone via the rostrolateral part of the fastigial nucleus..
The present study used single-unit recording and electrical microstimulation techniques in alert, trained rhesus monkeys to examine the involvement of the posterior interposed nucleus (IP) of the cerebellum in vergence and accommodative eye movements. The results of this study demonstrate the involvement of a specific region of the posterior interposed nucleus of the cerebellum in vergence and accommodation.
In this study, we investigated whether individual Purkinje cells of the C1 zone of the paramedian lobe of the rat innervate both groups of projection neurons in the anterior interposed nucleus.
Cerebellar nuclei [ the rostral interposed nucleus (INr) and the rostral fastigial nucleus (FNr)] known to be involved in respiratory control were ablated to determine their potential role in the cough response.
The major novel findings described and reviewed in the present study have all been demonstrated in the C2 module, which is formed by the rostral medial accessory olive, posterior interposed nucleus of the cerebellum, and zone C2. We show (1) that expression of dendritic lamellar bodies and dendrodendritic gap junctions in the rostral medial accessory olive are both down regulated by removal of the GABAergic input from the posterior interposed nucleus of the cerebellum to electrotonically coupled olivary dendrites; (2) that the high density of dendritic lamellar bodies in the rostral medial accessory olive can be correlated with a relatively high level of CS synchrony in the C2 zone of the flocculus; and (3) that the C2 zone of the flocculus is involved in head movements and probably gaze control.
In the cerebellar nuclei, immunoreactive cells were found in the medial part of the anterior interposed nucleus, in the interstitial cell groups, and within specific parts of the medial, posterior interposed, and lateral nuclei.
Expression of AT2 receptor mRNA was found in several thalamic nuclei (ventral posterolateral, mediodorsal, central medial, paracentral, and paraventricular), the medial geniculate nuclei, the nucleus of the optic tract, the subthalamic nucleus, the interposed nucleus of the cerebellum, and in the inferior olive.
The most lateral compartment is continuous with the C2 compartment of the paraflocculus and contains the posterior interposed nucleus.
In situ hybridization reveals a wide distribution in rat brain; in particular, abundant hybridization was detected in the hippocampus, cerebellum, habenula, reticular thalamic nucleus and interposed nucleus.
Terminals from the posterior interposed nucleus were located slightly rostral and lateral to those from the lateral nucleus, mainly around the border between the ventral lateral nucleus and the ventral posterior medial nucleus. Terminals from the anterior interposed nucleus were located slightly rostral and lateral to those from the posterior interposed nucleus, predominantly in the rostral pole of the ventral posterior lateral nucleus.
Stimulations of the anterior interposed nucleus caused both inspiratory and expiratory activities to increase, whereas no systematic changes followed stimulations of the vermis.
Injections restricted to LGv consistently labelled a small cluster of cells in the contralateral posterior interposed nucleus.
However, labelled cells were particularly concentrated in the ventrolateral corner of the contralateral posterior interposed nucleus and in the contralateral and, to a lesser extent, the ipsilateral fastigial nuclei. Injections of the posterior interposed nucleus labelled terminals in the portion of the supraoculomotor area dorsal to the fastigial projection and did not involve the Edinger-Westphal nucleus. Taken as a whole, these results demonstrate the presence of a highly specific pattern of labelling in the supraoculomotor area, which may indicate that the posterior interposed nucleus and the fastigial nucleus play different roles in the control of the near-response.
Labeling appeared in the red nucleus only when HRP encroached upon the posterior interposed nucleus..
The distribution of corticonuclear fibers to medial-most parts of the posterior interposed nucleus (NIP) from lateral areas of the vermis was studied in the squirrel monkey (Saimiri sciureus), using a silver impregnation method.
The medial part of the posterior interposed nucleus connects to caudolateral areas of the rostral half of the medial accessory olive, whereas lateral areas project to more rostromedial parts. Rostromedial projections to the dorsal accessory olive originate from the lateral part of the anterior interposed nucleus, whereas its medial parts project to more lateral and caudal regions of this olivary subnucleus.
The afferents of the fastigial nucleus (FN) were studied in two capuchin monkeys (Cebus apella) one of which had received a unilateral injection of horseradish peroxidase in the caudal FN, and a second monkey which received a control injection that involved the lateral caudal FN but extended into the cerebellar white matter between the FN and posterior interposed nucleus (PIN).
The other pathway is derived from cells in the posterior interposed nucleus and the adjacent posterior wing of the dentate nucleus, and it terminates contralaterally throughout the ventral half of the intermediate gray and the deep gray layers.
In the cerebellar nuclei, portions of the medial nucleus and magnocellular portion of the lateral nucleus had moderately dense networks of immunoreactive fibers, whereas loose networks of fibers were observed in the posterior interposed nucleus.
The caudal medial accessory olive (MAO) projected to FN, the rostral MAO to the posterior interposed nucleus (NIP), the rostral part of the dorsal accessory olive (DAO) to the anterior interposed nucleus (NIA), and the principal olive (PO) to LCN.(ABSTRACT TRUNCATED AT 400 WORDS).
HRP injection into the posterior interposed nucleus (PIN) resulted in labeling of P cells in the paravermal zone and of IO neurons in the rostral two-thirds of the MAO and the dorsal accessory olive (DAO).
One group of cats received a WGA-HRP injection in the posterior interposed nucleus of the cerebellum and another group received an injection in the nucleus of Darkschewitsch.
Antidromic field potentials and antidromic unit responses of Purkinje cells (PCs) to the stimulation of fastigial nucleus (FN), interposed nucleus (IN) and dentate nucleus (DN) were respectively recorded from the lobule VII of posterior cortex of decerebrated cats, to identify the corticonuclear projection in the lobule VII.
Thus, the anterior interposed nucleus receives fibres from all parts of the main NRL, its rostral part especially from laterally situated neurons, while subsequent more caudal parts from more medially situated neurons, while the posterior interposed nucleus receives fibres mainly from the dorsomedial part of the main NRL. No topical differences could be observed following ejections in different parts of the NRL; the majority of the projecting neurons were always concentrated along the ventral and lateral borders of the fastigial nucleus and in the adjacent medial part of the anterior interposed nucleus..
After injection of Phaseolus vulgaris-leucoagglutinin (PHA-L) into the interposed nucleus of the cat, labelled fibers were found in the granular layer as well as in the molecular layer of the cerebellar cortex.
Although termination was found in all the CCN, it was most pronounced in the lateral nucleus and the lateral aspect of the posterior interposed nucleus. The extreme lateral aspect of the anterior interposed nucleus and the caudal part of the fastigial nucleus received a projection of modest intensity. The projection of the NRTP to the ventrocaudal part of the lateral nucleus was found in conjunction with a projection to the ventrolateral part of the posterior interposed nucleus.
The largest number of single-TB-labeled (paraoculomotor-projecting) cells was observed in the medial cerebellar nucleus (MCN) and posterior interposed nucleus (PIN), whereas the largest number of single-DY-labeled (mPRF-projecting) cells was in the MCN.
No retrogradely labelled rubral cells were observed following implantations in the posterior interposed nucleus, and only very few such cells were identified in the contralateral red nucleus after implantations restricted to the anterior interposed nucleus with no contamination of cerebellar white matter or cortex. However, when WGA-HRP was delivered by a pressure injection, which in addition to the anterior interposed nucleus included the adjacent white cerebellar matter along the needle track and the overlying cortex, many retrogradely labelled cells were present contralaterally in the magnocellular red nucleus, with some also found in its rostral parvicellular part. The same observation was made when injection of free HRP exceeded the boundaries of the anterior interposed nucleus. Anterogradely labelled fibres could be followed from the implantations in the posterior interposed nucleus to a medial crescent of the entire contralateral red nucleus. Caudal as well as rostral parts of the posterior interposed nucleus project into the same area of the red nucleus. Implantations restricted to the anterior interposed nucleus label a projection to the contralateral magnocellular red nucleus which is topographically organized. The caudal part of the anterior interposed nucleus projects to the dorsomedial portion of the magnocellular red nucleus, the rostral part to its ventrolateral portion. In addition, a mediolateral organization in the anterior interposed nucleus coincides with a caudorostral arrangement in the red nucleus.
The nucleus reticularis tegmenti pontis contained a small number of retrogradely labelled cells after implantations in the anterior interposed nucleus, but none after implantations restricted to the posterior interposed nucleus.
The main projection from the anterior interposed nucleus reaches the rostral two thirds of the dorsal accessory olive, while the main projection from the posterior interposed nucleus reaches the rostral half of the medial accessory olive.
In the same monkeys, however, 78% of the neurons in the neighboring interposed nucleus were direction sensitive, and one-quarter of these displayed reciprocal patterns of discharge.
From the localization of the lesions in the cerebellar nuclei, as well as from the distribution of degenerations in the area of the LGv, it was postulated that the parent neurons for the cerebello-LGV fibers are located in the contralateral posterior interposed nucleus, although the anteroventral lateral cerebellar nucleus, the Y group and the infracerebellar nucleus have been not excluded.
After neonatal deep cerebellar nuclear lesions involving the dentate nucleus and the adjacent interposed nucleus, the cerebrocorticorubral fibers form similar synaptic contacts with somatic, dendritic and axonal profiles.
The fastigial and dentate nuclei contribute the majority of fibers to the dPRN whereas the interposed nucleus provides very little.
The interposed nucleus gives rise to a sparser projection, apparently limited to the ventral NRTP and immediate peripeduncular zones.
The interposed nucleus received a fair amount of heavy labeling only in the precentral arm and face cases.
Fibers from lateral areas of some vermal lobules appear to enter contiguous parts of the immediately adjacent posterior interposed nucleus.
Purkinje cells (P cells) in the intermediate zone of the cerebellar cortex as well as neurons of the interposed nucleus (IPN) were found to discharge with burst patterns fully synchronized with the drug-induced RN rhythm.
(1963) and its lateral part, (designated here as the lateral dentate, LD), and the neighboring interposed nucleus (NI), emerging fibres are numerous and leave laterally from the B.C.
Corticonuclear fibres from the flocculus terminate in an almost continuous band extending through the ipsilateral dentate nucleus and into the posterior interposed nucleus (through the nuclear regions previously designated cerebellar zones D2, D1 and C2).
The results showed that the cerebello-tectal projections arise from two different regions of the cerebellar nuclei: the caudal half of the medial nucleus and the ventrolateral part of the posterior interposed nucleus. Fibers arising from the medial nucleus distribute bilaterally in the superficial zone of the intermediate gray layer in the superior colliculus, while those originating from the posterior interposed nucleus terminate contralaterally in the deeper aspect of the intermediate gray layer and in the deep gray and white layers.
Thus the effects of the interposed nucleus concern preferably flexor muscles whereas the effects of the dentate nucleus appear to be equally distributed among flexor and extensor muscles. Somatotopic motor localization were evidenced both in the interposed and dentate nuclei: there are somatotopic relations between every region of the interposed nucleus and musculature.
There are 68,000 neurons in the dentate nucleus, 25,000 neurons in the posterior interposed nucleus, and 19,000 neurons in both the anterior interposed the fastigial nuclei.
Crus II receives input from neurons located predominately in the dentate nucleus, while the paramedian lobule is projected on by neurons located in a large postero-dorsal sector of the interposed nucleus and in a smaller medial strip of the dentate nucleus. Neurons in the ventral part of the dentate nucleus and the lateral part of the interposed nucleus send fibers to the paraflocculus.
The rostral medial accessory olive projects to zone C2 and sends collaterals to the posterior interposed nucleus. These fibers issue collaterals to the anterior interposed nucleus.
Nucleocortical fibers from the posterior interposed nucleus projected principally to the paramedian lobule, to the medial hemispheric area of Crus I and the lobus simplex, and to the flocculus and paraflocculus. Nucleocortical projections from the anterior interposed nucleus coursed to the anterior lobe paravermis and to the ventral folia of the paramedian lobule.
Cerebellar corticonuclear fibers of both dorsal (Dpf) and ventral (Vpf) divisions of the paraflocculus terminate in the lateral cerebellar nucelus (NL) and in the posterior interposed nucleus (NIP).
Caudal dorsal accessory olive projects to lateral vermal zone B in lobules I-VI, Deiters' nucleus and dorsomedial subnucleus of interposed nucleus.
-
[ View All ]
