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  • 11
    Electronic Resource
    Electronic Resource
    Integration in descending motor pathways controlling the forelimb in the cat (1976)
    Springer
    Experimental brain research 26 (1976), S. 521-540 
    Details
    ISSN: 1432-1106
    Keywords: Forelimb motoneurones ; Disynaptic pyramidal EPSPs ; Intercalated neurones ; Convergence ; Rubrospinal fibres ; Primary forelimb afferents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With intracellular recording from forelimb motoneurones the spatial facilitation technique has been used to investigate interaction between descending pathways and forelimb afferents. As previously shown for the hindlimb, pyramidal volleys effectively facilitate interneuronal transmission in reflex pathways from different primary afferents. Evidence is presented suggesting disynaptic excitation from corticospinal fibres of interneurones in the reciprocal Ia inhibitory pathway. Interneurones of other reflex pathways from group I muscle afferents receive monosynaptic pyramidal excitation. During pyramidal facilitation volleys in cutaneous afferents may evoke PSPs in motoneurones after a central delay of 1.3 ms suggesting that the minimal linkage is disynaptic. Information regarding convergence on the neurones intercalated in the disynaptic cortico-motoneuronal pathway was obtained by investigating the effect from primary afferents and from other descending pathways on the disynaptic pyramidal EPSPs. Volleys in cutaneous and group I muscle afferents facilitate transmission in the disynaptic cortico-motoneuronal pathway with a time course showing oligosynaptic (probably monosynaptic) action on the intercalated neurone. Rubrospinal volleys likewise effectively facilitate disynaptic cortico-motoneuronal transmission with a time course showing monosynaptic action on the intercalated neurone. Spatial facilitation experiments involving three tests revealed that those intercalated neurones which receive convergent monosynaptic excitation from corticospinal and rubrospinal fibres are excited also from cutaneous forelimb afferents. Disynaptic cortico-motoneuronal transmission was also monosynaptically facilitated by stimuli in the dorsal mesencephalic tegmentum probably activating tectospinal fibres. Disynaptic, presumed tectospinal EPSPs were facilitated from cutaneous forelimb afferents. The convergence onto the neurones intercalated in the disynaptic excitatory cortico-motoneuronal pathway suggests that these neurones integrate the activity in different descending pathways and primary forelimb afferents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238825
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  • 12
    Electronic Resource
    Electronic Resource
    Integration in descending motor pathways controlling the forelimb in the cat (1978)
    Springer
    Experimental brain research 33 (1978), S. 101-130 
    Details
    ISSN: 1432-1106
    Keywords: Cortico-, rubro and tectospinal tracts ; Cervical primary afferents ; Monosynaptic EPSPs ; Propriospinal neurones C3-C4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recording was made in the C3-C4 segments from cell bodies of propriospinal neurones identified by their antidromic activation from more caudal segments. Monosynaptic excitatory effects from descending motor pathways and primary afferents were investigated by electrical stimulation of higher motor centres and peripheral nerves in the forelimb and neck. The cell bodies were located mainly laterally in Rexed's layer VII. Threshold mapping for single axons showed that they descend in the lateroventral part of the lateral funicle. Antidromic stimulation at different spinal cord levels showed that some neurones terminated in the forelimb segments, others in the thoracic cord or in the lumbar segments. Terminal slowing of the conduction velocity suggested axonal branching over some segments. Monosynaptic EPSPs were evoked in the neurones by stimulation of the contralateral pyramid, red nucleus and dorsal tegmentum-superior colliculus. It is concluded that corticospinal, rubrospinal and tectospinal fibres project directly to both short and long propriospinal neurones. There was marked frequency potentiation in tectospinal synapses. Convergence from two descending tracts was common and in half of the tested cells all three tracts contributed monosynaptic excitation. Experiments with collision of descending volleys and antidromic volleys from the brachial segments demonstrated that the corticospinal and rubrospinal monosynaptic projection to the propriospinal neurones is by collaterals from fibres continuing to the forelimb segments. Stimulation of cervical primary afferents in the dorsal column gave monosynaptic EPSPs in somewhat less than half of the tested propriospinal neurones. The further analysis with stimulation of forelimb nerves and C2-C3 dorsal rami showed that monosynaptic EPSPs may be evoked from low threshold cutaneous and group I muscle afferents in the forelimb and from C2-C3 neck afferents entering close to the spinal ganglia, possibly from joint receptors. Convergence from cervical afferents and at least two of the above descending tracts was common. It is postulated that the propriospinal neurones previously indirectly defined by their action on motoneurones as relaying disynaptic excitation from higher motor centres to forelimb motoneurones (Illert et al., 1977) belong to those neurones of the C3-C4 propriospinal systems which terminate in the cervical enlargement. The function of the neurones projecting beyond the upper thoracic segments is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238798
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  • 13
    Electronic Resource
    Electronic Resource
    Integration in descending motor pathways controlling the forelimb in the cat. 4. Corticospinal inhibition of forelimb motoneurones mediated by short propriospinal neurones (1978)
    Springer
    Experimental brain research 31 (1978), S. 131-141 
    Details
    ISSN: 1432-1106
    Keywords: Forelimb motoneurone ; Trisynaptic pyramidal IPSP ; Propriospinal neurone ; Ia inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A previously described inhibitory trisynaptic cortico-motoneuronal pathway (Illert et al., 1976a) was analysed in order to identify the two relay stations. Intracellular recording was made from motoneurones to elbow muscles. Corticospinal fibres were stimulated in the contralateral medullary pyramid. Pyramidal IPSPs were abolished by a transection of the Corticospinal tract in C2 but remained after a corresponding lesion in C5. After a C5 lesion pyramidal volleys facilitated transmission in the Ia inhibitory pathway with a time course suggesting disynaptic excitatory action on the Ia inhibitory interneurones. The trisynaptic pyramidal IPSPs were depressed by volleys in the appropriate recurrent motor axon collaterals as would be expected if these IPSPs were mediated by Ia inhibitory interneurones. It is concluded that trisynaptic cortico-motoneuronal inhibition is evoked by consecutive activation of propriospinal neurones in C3-C4 and segmental Ia inhibitory interneurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235810
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  • 14
    Electronic Resource
    Electronic Resource
    Solitary plasmacytomas of the occipital bone: a report of two cases (1997)
    Springer
    European radiology 7 (1997), S. 503-506 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Skull ; Occipital bone ; Plasmacytoma ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The radiological appearances of two cases of solitary plasmacytoma in the occipital bone are described. One arose in the lateral part and the other in the squama. They showed characteristic radiological features on CT, MRI and angiography. Bone scintigraphy and gallium scintigraphy were also available. Solitary plasmacytoma of the skull is a rare condition and usually occurs in the calvarium. The skull base is an extremely rare site and only four cases have been reported. The literature of solitary plasmacytoma of the skull is reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050192
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  • 15
    Electronic Resource
    Electronic Resource
    Reciprocal Ia inhibition during voluntary movements in man (1974)
    Springer
    Experimental brain research 21 (1974), S. 529-540 
    Details
    ISSN: 1432-1106
    Keywords: Man ; H-reflex ; Reciprocal Ia inhibition ; Voluntary movements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects on the H-reflex of the triceps surae muscle from the volleys in the common peroneal nerve were investigated in normal human subjects at rest and during voluntary ankle movements. A depressive effect was revealed during active dorsiflexion but not at rest. Since this depression was evoked by volleys of low-threshold afferents and had a very short latency which suggests a disynaptic linkage, it was regarded as the reciprocal Ia inhibition. In an exceptional case, which showed an H-reflex in pretibial muscles at rest in spite of normal central nervous functions, reciprocal Ia inhibition of the triceps surae as well as pretibial motoneurones was observed in a resting state. It was stressed that there is a close parallelism between the excitability of a group of a-motoneurones and of interneurones which mediate Ia inhibition of the antagonists. Relying on recent observations from animal experiments neuronal mechanisms of the present observation were discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237171
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  • 16
    Electronic Resource
    Electronic Resource
    Integration in descending motor pathways controlling the forelimb in the cat (1977)
    Springer
    Experimental brain research 29 (1977), S. 323-346 
    Details
    ISSN: 1432-1106
    Keywords: Cortico-, rubro- and tectospinal tracts ; Forelimb afferents ; Short propriospinal neurones ; Forelimb motoneurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A previously described disynaptic pathway from cortex to forelimb motoneurones whose intercalated neurones were excited both from other descending pathways and from forelimb afferents (Illert et al., 1976a, b) has been further analysed, mainly with respect to the location of the relay cells and their axons. Disynaptic EPSPs evoked in forelimb motoneurones by stimulation of the pyramid remained after complete transection of the corticospinal tract in C5 rostral to the forelimb segments but were abolished after a more rostral transection of the tract in the C2 segment. Corresponding findings were made with disynaptic rubral EPSPs after transection of the rubrospinal tract in these segments. It is concluded that disynaptic cortico-motoneuronal and rubro-motoneuronal excitation is relayed by propriospinal neurones originating in the C3–C4 segments. Other lesion experiments revealed that the axons of these propriospinal neurones descend to forelimb motoneurones in the ventrolateral part of the lateral funicle. Spatial facilitation of transmission from the corticospinal and rubrospinal tracts after transection of them in C5 occurred with a time course showing monosynaptic convergence from these pathways on common propriospinal neurones. Facilitation of disynaptic pyramidal EPSPs from the dorsal tegmentum remained after transection of the corticospinal tract at C5 but was abolished after a transection at C2. It is postulated that corticospinal and presumed tectospinal fibres converge onto common neurones in the propriospinal relay but evidence is also given for a more rostral relay (probably bulbar) with a similar convergence. The oligo- (probably mono-)synaptic facilitation of the disynaptic pyramidal EPSP evoked by volleys in cutaneous and group I muscle afferents from the forelimb likewise remained after a C5 transection of the corticospinal tract but was abolished after an additional C5 lesion in the dorsal column. It is concluded that propriospinal relay cells receive excitatory action from forelimb afferents ascending in the dorsal column. Spatial facilitation experiments using three tests revealed that propriospinal neurones monosynaptically excited from both corticospinal and rubrospinal fibres also receive excitation from cutaneous forelimb afferents. It is postulated that the propriospinal relay provides an important route for fast activation of forelimb motoneurones from the brain. The convergent monosynaptic excitation from several important motor centres in the brain is considered in relation to the general problem of the functional relationship between higher motor centres. The convergent action from forelimb afferents is taken to suggest that a descending command for a forelimb movement can be modified from the forelimb while on its way to the motoneurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236174
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  • 17
    Electronic Resource
    Electronic Resource
    Integration in descending motor pathways controlling the forelimb in the cat (1980)
    Springer
    Experimental brain research 38 (1980), S. 87-93 
    Details
    ISSN: 1432-1106
    Keywords: C3–C4 Propriospinal neurones ; Forelimb motoneurones ; Intraspinal HRP injections
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Short cervical propriospinal neurones projecting to cat forelimb segments were identified and compared in their longitudinal segmental location and transverse distribution with a propriospinal relay recently described in C3–C4 with electrophysiological methods (Illert et al., 1977, 1978). Localized horseradish peroxidase injections into the C6–C7 forelimb motornuclei demonstrated propriospinal cells in rostral cervical segments. The multiple injection technique in combination with control experiments seemed to allow delimitation of the uptake region in the ventral horn responsible for the retrograde cell labelling. Injections laterally in the ventral horn labelled propriospinal neurones ipsilaterally in C3–C5, mainly in the lateral parts of laminae VI and VII. More medially located injections labelled cells with a similar distribution ipsilaterally, but contralateral cells were found in addition. They were located in laminae VII and VIII of the C2–C5 segments, mainly medially. The evidence is discussed that the neurones located laterally in the C3–C4 segments project directly to ipsilateral forelimb motoneurones and, under this assumption, it is postulated that they constitute the C3–C4 propriospinal relay (Illert et al., 1977) and are identical with the neurones of the “C3–C4 propriospinal system” (Illert et al., 1978).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237934
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  • 18
    Electronic Resource
    Electronic Resource
    Changes in reciprocal ia inhibition during voluntary contraction in man (1984)
    Springer
    Experimental brain research 53 (1984), S. 400-408 
    Details
    ISSN: 1432-1106
    Keywords: H-reflex ; Ia inhibition ; Tonic voluntary contraction ; Ankle muscles ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Reciprocal Ia inhibition from ankle flexors to extensors was studied during voluntary tonic isometric dorsiflexion and plantar flexion in five normal subjects. The Ia inhibition was examined as the short-latency suppression of the soleus H-reflexes by stimulation of the low-threshold afferents in the common peroneal nerve (Mizuno et al. 1971). At rest, weak Ia inhibition was demonstrated in four subjects out of five, the maximal amount being 14.1 ± 5.0% suppression of the control H-reflex. The absolute amount of inhibition, which was calculated by subtracting the mean size of the conditioned H-reflex from that of the control H-reflex and expressed as a percentage of the maximal M-response, increased during ankle dorsiflexion, and decreased or disappeared during plantar flexion in parallel with the amount of contraction. The neural mechanisms for facilitation of the Ia inhibitory pathway during dorsiflexion were considered to support the hypothesis of “α-γ-linkage in reciprocal inhibition”, i.e. combined facilitatory effects on the Ia inhibitory interneurone from the supraspinal centers directly and indirectly via the γ motoneurone — Ia afferent route. The mechanism for inhibition of the pathway during plantar flexion was considered to be inhibition of the Ia interneurone of the flexor side by Ia interneurone of antagonist extensors. A quantitative aspect of activity in the reciprocal Ia inhibitory pathway on the performance of voluntary movement is revealed in this study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238170
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  • 19
    Electronic Resource
    Electronic Resource
    The long-term growth rate of residual acoustic neurinomas (1994)
    Springer
    Acta neurochirurgica 129 (1994), S. 127-130 
    Details
    ISSN: 0942-0940
    Keywords: Acoustic neurinoma ; computed tomography ; growthrate ; intracapsular removal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The growth rate of 19 residual acoustic neurinomas was examined in a long-term follow-up study (median, 10 years; range, 5 to 17 years) following intracapsular removal. Of these, 10 (53%) had regrowth, three (16%) showed regression, and six (32%) were unchanged. The 10 acoustic neurinomas showing regrowth were divided into two categories, either solid or cystic, according to computed tomographic findings. Five acoustic neurinomas with cyst formation showed rapid regrowth, with the tumour doubling time ranging from 0.15 to 5.0 years (median, 4.5 years), and required re-operation. Five solid tumours showed slow regrowth, with the tumour doubling time ranging from 9 to 34 years (median, 15 years). Although cyst formation is a major factor in rapid regrowth, residual acoustic neurinomas without cyst formation have a slower growth potential. In this study, 74% of the residual acoustic neurinomas have never required re-operation. It is advisable to choose intracapsular removal if there is major risk of neurological deficits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01406491
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  • 20
    Electronic Resource
    Electronic Resource
    Anomaly of venous system in congenital occipital dermal sinus (1994)
    Springer
    Acta neurochirurgica 128 (1994), S. 174-179 
    Details
    ISSN: 0942-0940
    Keywords: Congenital occipital dermal sinus ; dural sinuses ; development ; embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report two cases of congenital occipital dermal sinus in which elongation of the vein of Galen, elevation of the straight sinus, division of the superior sagittal sinus, elevation of the confluence of sinuses, elevation of transverse sinus and narrowing of the torcular angle were observed in the venous phase of cerebral angiography. Enhanced computed tomography (CT) revealed enlargement of the supracerebellar cistern, elevation of the straight sinus and of the confluence of sinuses, but no evidence of intracranial lesions. In order to study the relationship between anomalies in the dural venous sinuses and congenital occipital dermal sinus, we examined both cases from an embryological viewpoint.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01400671
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