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  • 1
    Electronic Resource
    Electronic Resource
    Projection of the cerebellar dentate nucleus onto the frontal association cortex in monkeys (1979)
    Springer
    Experimental brain research 37 (1979), S. 193-198 
    Details
    ISSN: 1432-1106
    Keywords: Cerebello-cerebral projection ; Dentate nucleus ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stimulation of the cerebellar dentate nucleus in monkeys elicited responses in the frontal association cortex (area 9) on the contralateral side to the stimulation, in addition to those in the motor (area 4) and premotor (area 6) cortices which were reported previously. The responses in the frontal association cortex were characterized by surface positive-deep negative field potentials in the cortex. They contrasted with surface negative-deep positive potentials in the motor and premotor cortices on the same dentate nucleus stimulation. In the rostral part of the premotor cortex (area 6) on the border of area 9, both types of responses were induced and admixed. The relay nucleus of the thalamus was suggested for the dentate-induced responses in the frontal association cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01474266
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  • 2
    Electronic Resource
    Electronic Resource
    Electrophysiologic studies on the pallido- and cerebellothalamic projections in squirrel monkeys (Saimiri sciureus) (1983)
    Springer
    Experimental brain research 51 (1983), S. 77-87 
    Details
    ISSN: 1432-1106
    Keywords: Pallidum ; Cerebellar nuclei ; Thalamus ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thalamic projections of the pallidum and the deep cerebellar nuclei were studied by unitary recordings as well as field potential analysis in the thalamus of squirrel monkeys (Saimiri sciureus) under sodium pentobarbital anesthesia. Stimulation of the pallidum produced a positive field potential preceded by incoming afferent fiber volleys in the thalamus. Spontaneous discharges of thalamic neurons were suppressed during this positive potential, and intracellular recordings from the thalamic neurons revealed that the time course of this field potential corresponded to that of the hyperpolarizing potential. The hyperpolarization was presumed to be a monosynaptic inhibitory postsynaptic potential by the short synaptic delay (about 0.5–0.7 ms) and responsiveness to high frequency stimulation (over 150 Hz). The positive field potential on stimulation of the external pallidal segment was distributed in L.po (VA) and the reticular thalamic nucleus around L.po, whereas that on stimulation of the internal segment was in V.o.a (the anterior basal part of VL) and in Z.o (upper part of VL). The projection of the external segment appeared to be less dense than that of the internal segment. The projection of deep cerebellar nuclei was situated in V.o.a, V.o.p (posterior part of basal part of VL), V.o.i (VLm), the intralaminar nucleus (CL), and some part of V. im (the rostral part of VPLo). Projections of the interpositus and dentate nuclei were distributed in a more anterior part than those of the fastigial nucleus. A certain topographical arrangement of the projections of these three nuclei was found in V.o.p, V.o.i and V.im. No significant overlap was detected between projections of the pallidum and the deep cerebellar nuclei within the thalamus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236805
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  • 3
    Electronic Resource
    Electronic Resource
    Cortical field potentials preceding visually initiated hand movements and cerebellar actions in the monkey (1982)
    Springer
    Experimental brain research 46 (1982), S. 29-36 
    Details
    ISSN: 1432-1106
    Keywords: Premovement cortical potential ; Visually initiated movement ; Cerebellum ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cortical field potentials preceding hand movements initiated by a visual stimulus were recorded with chronically implanted electrodes in premotor, motor and somatosensory cortices of monkeys, and the influences of cerebellar hemispherectomy on cortical potentials as well as reaction time of movements were examined. As reported previously, early surface-positive, depth-negative (2.5–3 mm depth from the cortical surface) premovement potentials emerged at about 40 ms latency after onset of the light stimulus bilaterally in premotor and forelimb motor areas. Early potentials in the forelimb motor area contralateral to the moving hand were followed at about 120 ms latency by surface-negative, depth-positive late premovement potentials which are considered to be mainly composed of superficial thalamo-cortical (T-C) responses. Unilateral hemispherectomy of the cerebellum contralateral to the motor area immediately eliminated the surface-negative, depth-positive potentials. Reaction time from onset of the light stimulus to the hand movement was prolonged by 90–250 ms after cerebellar hemispherectomy. If the dentate and interpositus nuclei were also lesioned, disappearance of the late potentials and delay of the movement continued for many months. However, if the interpositus was spared, there was earlier recovery of reaction time with simultaneous reappearance of the late premovement potentials in the motor cortex. The conclusion is drawn that the cerebellar hemisphere (neocerebellum) activates the motor cortex via superficial T-C projections and participates directly in the initiation of reaction movements in response to an external stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238095
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on cortical field potentials recorded during learning processes of visually initiated hand movements in monkeys (1984)
    Springer
    Experimental brain research 55 (1984), S. 26-32 
    Details
    ISSN: 1432-1106
    Keywords: Cortical field potential ; Visually initiated movement ; Motor learning ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A monkey was trained to lift a lever by wrist extension in response to a light stimulus. During the learning process of the task over several months, field potentials related not only to the task performance but also to substitution and stimulation experiments were recorded with chronically implanted electrodes on the surface and at a depth of 2.5–3.0 mm in the prefrontal, premotor, motor and prestriate cortices. In the substitution experiment, an examiner lifted a lever for the monkey so that it was watching the light and rewarded without the hand movement. In the stimulation experiment, the same light stimulus was simply delivered to the monkey. In a naive monkey which lifted the lever independently of the stimulus, stimulus-locked potentials were evoked by the task experiment in those cortices except the motor cortex, but none was elicited by the substitution or stimulation experiment. In a welltrained monkey, the substitution and stimulation experiments induced almost the same potentials as those prior to the task movement in respective cortices except the motor cortex, in which the component of cerebellar-induced premovement potential was not observed during the substitution and stimulation experiments. At an intermediate stage of learning, the situation was intermediate between the naive and well-trained stages and most premovement potentials except those in the motor cortex were elicited by the substitution experiment in reduced sizes, but nothing by the stimulation experiment. The present study suggests that the neuronal circuits for the operantly conditioned movement are functionally organized and gradually consolidated in the learning process, and that the consolidation is made earlier for the circuit involving association and premotor cortices than the circuit including the motor cortex in the process. The circuit to the motor cortex via the cerebro-cerebellar interconnection is recruited only on the execution of movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240495
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  • 5
    Electronic Resource
    Electronic Resource
    A comparison of the inhibitory actions of Golgi cells and of basket cells (1967)
    Springer
    Experimental brain research 3 (1967), S. 81-94 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellar inhibition ; Golgi cells ; Basket cells ; Purkinje cells ; Granule cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. There has been a comparative study of two kinds of inhibition in the cerebellar cortex: basket cell inhibition of Purkinje cells; and Golgi cell inhibition of granule cells. These inhibitory actions were assayed by the degree of inhibition of the potential waves that juxta-fastigial (J.F.) stimulation evoked in the granular or molecular layers: basket cell inhibition by the N1 wave generated by antidromic invasion of Purkinje cells; and Golgi cell inhibition of the N3 or P2 waves evoked by the mossy fibre volley in the molecular and granular layers respectively. 2. The Golgi cell inhibition produced by a parallel fibre volley (LOC stimulation) extended transversely for no more than 200 μ on either side of the narrow beam of the excited parallel fibres, whereas the spread of basket cell inhibition was much larger — to as far as 1 mm. 3. When activated by the on-beam LOC stimulation, the Golgi cell and the basket cell inhibition showed much the same threshold of the stimulation. The off-beam LOC stimulation produced only the basket cell inhibition which is in conformity with the different transverse distributions described in (2) above. 4. When evoked by J. F. or trans-folial (T. F.) stimulation, the Golgi cell inhibition had a much lower threshold than the basket cell inhibition. It is suggested that in part at least this is attributable to the direct synaptic connection from mossy fibres to Golgi cells. 5. The Golgi cell inhibition elicited by the LOC stimulation showed a relatively short time course, the maximum being attained by about 10 msec, after which there was an approximately exponential decrease so that the total duration was only about 100 msec. On the other hand, the basket cell inhibition had a much slower time course, maximum being attained at a latency of 20 to 40 msec, the total duration being even in excess of 200 msec. Suggestions are made with respect to the factors responsible for the slow time course of the basket cell inhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234471
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  • 6
    Electronic Resource
    Electronic Resource
    Cortical field potentials preceding visually initiated hand movements in the monkey (1981)
    Springer
    Experimental brain research 42 (1981), S. 435-441 
    Details
    ISSN: 1432-1106
    Keywords: Premovement cortical potential ; Visually initiated movement ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With electrodes implanted chronically on the surface and in the depth of the cortex, field potentials were led from the premotor cortex and forelimb areas of the motor and somatosensory cortices of monkeys performing visually initiated hand movements, and then averaged. It was found that the visually initiated movement was preceded by early (latency about 40 ms after the visual stimulus), surface positive, depth negative potentials in the premotor and forelimb motor cortices on both sides. Later on (at about 120 ms latency), surface negative, depth positive potentials emerged prior to the movement in the motor cortex contralateral to the moving hand. The early responses were interpreted as being induced via deep thalamo-cortical and/or corticocortical projections, while the later responses were via superficial thalamo-cortical projections, according to laminar field potential analyses of cortical evoked potentials made in our previous acute experiments. These potentials were clearly different from the premovement potentials recorded in the respective cortices prior to self-paced hand movements: monkeys performing self-paced hand movements showed slowly increasing, surface negative, depth positive premovement potentials in the premotor cortex and the forelimb motor and somatosensory areas contralateral to the moving hand. It was concluded that the central nervous mechanism preparing the cerebral cortex for visually initiated movements is considerably different from that for self-paced movements, both of which consist of the same wrist extension in lifting a lever.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237508
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  • 7
    Electronic Resource
    Electronic Resource
    Compensatory motor function of the somatosensory cortex for the motor cortex temporarily impaired by cooling in the monkey (1984)
    Springer
    Experimental brain research 55 (1984), S. 60-68 
    Details
    ISSN: 1432-1106
    Keywords: Compensatory motor function ; Somatosensory cortex ; Motor cortex cooling ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The motor cortex was temporarily impaired by local cooling during repeated execution of visually initiated hand movements in monkeys. The effects of cooling were examined by recording premovement cortical field potentials in the forelimb motor and somatosensory cortices and by measuring reaction time and force exerted by the movement. The cortex was cooled by perfusing cold water (about 1° C) through a metal chamber placed on the cortical epidural surface. Cooling of the forelimb motor area lowered temperature of the cortex under the chamber to 20–29° C within 4–5 min. Recording electrodes for cortical field potentials were implanted chronically on the surface and at 2.5–3.0 mm depth of various cortical areas including that being cooled. Spread of cooling to surrounding cortical areas was prevented by placing chambers perfused with warm water (38–39° C) on the areas. Cooling of the forelimb motor area greatly reduced its premovement cortical field potentials, followed by prolonged reaction times of weakened contralateral wrist muscles. Simultaneous recording from the primary somatosensory cortex revealed an enhancement of its premovement field potentials. All changes were completely reversible by rewarming of the motor cortex. Concomitant cooling of the motor and somatosensory cortices entirely paralysed the contralateral wrist muscles. These results suggest that the motor function of the somatosensory cortex becomes predominant and compensates for dysfunction of the motor cortex when it is temporarily impaired.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240498
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  • 8
    Electronic Resource
    Electronic Resource
    Development and change of cortical field potentials during learning processes of visually initiated hand movements in the monkey (1982)
    Springer
    Experimental brain research 48 (1982), S. 429-437 
    Details
    ISSN: 1432-1106
    Keywords: Cortical field potential ; Visually initiated movement ; Motor learning ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Field potentials on the surface and at 2.5–3.0 mm depth in the cerebral cortex were recorded in various areas with chronically implanted electrodes and the potentials which preceded hand movements in response to a light stimulus were observed during the process of learning the skilled conditioned movement. A naive monkey had to lift a lever by wrist extension within duration of the light stimulus lasting for 900, 700 or 510 ms depending on the stage of the learning process. In addition to some responses in the striate gyrus, significant short-latency responses to the light stimulus appeared bilaterally in certain areas of the prefrontal and prestriate cortices at an early stage of learning in which the monkey still lifted the lever randomly, and they became gradually larger as the monkey was trained further. Short-latency responses were also often noted in the bilateral premotor cortices during an early stage of learning. When the monkey started to respond to the stimulus by the appropriate movement, early surface-positive (s-P), depth-negative (d-N) premovement potentials appeared in the forelimb motor cortex, and the responses in the premotor cortex increased in size. As the movement became faster and more skillful, late s-N, d-P premovement potentials, that are known to be mediated by the neocerebellum and superficial thalamo-cortical projections, emerged after the early s-P, d-N potentials and became more marked, larger and steeper in the forelimb motor cortex contralateral to the moving hand. All the premovement potentials in the different cortical areas thus developed into steady and constant states and remained so for many months thus maintaining their established patterns. Such successive appearances of premovement field potentials in various cortical areas were related to learning processes of the movement and the implication of these findings was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238619
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  • 9
    Electronic Resource
    Electronic Resource
    Compensatory motor function of the somatosensory cortex for dysfunction of the motor cortex following cerebellar hemispherectomy in the monkey (1984)
    Springer
    Experimental brain research 56 (1984), S. 532-538 
    Details
    ISSN: 1432-1106
    Keywords: Compensatory motor function ; Somatosensory cortex ; Cerebellar hemispherectomy ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrical activities of the motor and somatosensory cortices preceding visually-initiated hand movements were recorded with electrodes chronically implanted on the surface and at 2.5–3.0 mm depth in the cortex of monkeys, and changes in field potentials in these cortices after cerebellar hemispherectomy were observed for many weeks. As previously reported, a unilateral cerebellar hemispherectomy including the lateral and interpositus nuclei eliminates the cerebellar-mediated superficial thalamo-cortical (T-C) responses recorded in the forelimb motor cortex contralateral to the hemispherectomy. These T-C responses normally precede the hand movement, and the operation results in the delay of movement initiation. The electrodes in the forelimb area of the contralateral primary somatosensory cortex showed an enhancement of superficial T-C responses of the somatosensory cortex for 30–40 days after the operation. The enhanced potentials preceded the delayed movement as do the cerebellar-mediated superficial T-C responses of the motor cortex in normal situations. Local cooling of the somatosensory cortex following the cerebellar hemispherectomy disturbed the reaction time movement for a few weeks after the operation. This effect was rarely encountered in normal monkeys. The present study suggests the compensatory motor function of the somatosensory cortex for the dysfunction of the motor cortex in early weeks after cerebellar hemispherectomy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237994
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  • 10
    Electronic Resource
    Electronic Resource
    The profiles of physiological events produced by a parallel fibre volley in the cerebellar cortex (1966)
    Springer
    Experimental brain research 2 (1966), S. 18-34 
    Details
    ISSN: 1432-1106
    Keywords: Cerebellum ; Parallel fibres ; Basket cells ; Purkinje cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Stimulation through concentric electrodes on the surface of a wide cerebellar folium was employed to set up a parallel fibre volley or beam. Serial recording of the field potential was made over a range of depths along microelectrode tracks arranged in a transverse plane across the folium in order to discover the action on Purkinje cells, both those that were on-beam for the parallel fibre volley and those at various distances off-beam. A juxta-fastigial electrode was carefully placed so that an applied stimulus could excite the axons of Purkinje cells distributed across the folium under investigation, the antidromic propagation of impulses thus obtained being utilized to test the effect of parallel fibre volleys upon Purkinje cells. 2. The observations were in accord with the two actions that a parallel fibre volley would be expected to exert on Purkinje cells: a direct excitatory action by the synapses made by parallel fibres with the spines of the Purkinje cell dendrites; an inhibitory action mediated by the stellate and basket cells that themselves are directly excited by the parallel fibre volley. 3. The excitatory synaptic action would result in the two types of responses that were restricted to the narrow zone and superficial location of the parallel fibre volley: active sinks formed by this excitatory synaptic action on the superficial dendrites of Purkinje cells would account for the observed depth profile of extra-cellular slow potentials, a superficial negative wave reversing to a deeper positive wave formed by passive sources on deeper dendrites; superficial synaptic excitation would also account for the facilitation of the propagation of antidromic impulses into the superficial dendrites. 4. The inhibitory synaptic action would result in the two types of responses that were widely dispersed transversely and in depth, far beyond the traject of the parallel fibre volley: a slow positive potential wave with a maximum at a depth usually of 300–400 μ; an inhibitory action on the antidromic invasion of Purkinje cells. The transverse profiles of these two presumed indices of inhibitory action on Purkinje cells apparently revealed that a basket cell may give inhibitory synapses up to 1000 μ laterally from the location of its soma and dendrites. 5. A description is given of the variants in the transverse profiles of the deeper positive waves and of inhibitory actions of a parallel fibre volley that presumably are mediated by basket cells and also by the superficial stellate cells. These physiological findings are correlated with the histologically determined distribution of synapses from a basket cell onto Purkinje cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234358
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