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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 55 (1984), S. 26-32 
    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
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 48 (1982), S. 429-437 
    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
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 65 (1987), S. 649-657 
    ISSN: 1432-1106
    Keywords: Audio-initiated hand movement ; Cortical field potential ; Cerebellar hemispherectomy ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Monkeys were trained to respond to auditory stimulus by lifting a lever (audio-initiated hand movement), and field potentials were recorded. from various cortical areas with electrodes implanted on the surface and at a depth of 2.0–3.0mm, depending on the area. Tones of 500, 1000 and 2000 Hz were given to the monkey for about 500 or 10 ms, as auditory stimuli. In association with the movement, potentials of different configurations were recorded respectively in the primary auditory, auditory association, prefrontal, premotor, motor and somatosensory cortices. Initial surface-positive (s-P), depthnegative (d-N) potentials appeared in the primary auditory and auditory association cortices about 20 ms after the onset of the auditory stimulus, and they were often followed by s-N, d-P potentials. In the forelimb area of the motor cortex contralateral to the moving hand, s-N, d-P potentials appeared at a latency of about 100 ms. Following cerebellar hemispherectomy ipsilateral to the moving hand, the s-N, d-P potentials in the forelimb motor cortex were eliminated and reaction times prolonged. The same monkeys were also trained to perform a visuoinitiated movement, and results were compared with each other. Primary sensory and sensory association areas activated during such movements were certainly different, and the prefrontal association cortex appeared to participate much less predominantly in the audio- than in the visuo-initiated movement. Reaction times were generally longer and more variable for the audio- than for the visuo-initiated movement. Nevertheless the cerebello-thalamomotor cortical projection was found to be recruited in the same manner prior to both movements.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1106
    Keywords: Prefrontal cortex ; Cortical field potential ; Reaction time movement ; Colour discrimination ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Monkeys were trained to perform hand movements in a reaction time task with discrimination between positive (go) and negative (no-go) light signals, and field potentials in various cortical areas were recorded and analysed with chronically implanted cortical electrodes. As previously reported, areas such as the prefrontal, premotor and motor cortices were active in association with simple visually-initiated, reaction-time hand movements. The caudal part of the dorsal bank of the principal sulcus was found to be activated specifically on no-go trials during discrimination, and revealed a relatively sharp surface-negative, depth-positive potential. The potential appeared at a latency of 110–150 ms, which was 150–210 ms earlier than the movement onset on go trials. With reversal of the go and no-go signals, this potential was found to be recorded only on no-go trials, irrespective of the colour used for the stimulus. It is suggested that the activity in the dorsal bank of the principal sulcus is related to the judgement not to execute the movement and/or the suppression of motor execution.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell reports 19 (2000), S. 1021-1026 
    ISSN: 1432-203X
    Keywords: Key words Atropa belladonna ; Hairy root ; Littorine ; Root growth ; Tropane alkaloid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Aseptically propagated regenerates were cultivated in a hydroponic apparatus, a phytotron or in the field, and their growth and littorine contents were investigated. No littorine was detected in aseptic regenerates cultured on solidified Murashige and Skoog medium, nor was it found in leaves under the three conditions tested. In roots, it was common features to all three conditions tested that littorine increased dramatically after transplantation from culture tubes and was a major alkaloid up to week 4; subsequently the littorine contents varied depending on the cultivation conditions. Roots cultivated in the field showed a marked thickening and rapid disappearance of littorine; those cultivated in the hydroponic apparatus were thin and maintained a high level of littorine for a long time. In a plant cultivated for 16 weeks in a pot, littorine content in the roots decreased with increasing root diameter.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 70 (1988), S. 43-49 
    ISSN: 1432-1106
    Keywords: Audio-initiated hand movement ; Cortical field potential ; Motor learning ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Field potentials on the surface and at a depth of 2.0–3.0 mm in the cerebral cortex were recorded with chronically implanted electrodes in various areas of a monkey. The potentials associated with movements in response to auditory stimuli (audio-initiated hand movement) were observed during the learning process of the movement. The monkey had to lift a lever by wrist extension within the duration of the stimulus (tone of 1000 Hz) lasting for about 900, 700 or 500 ms depending on the stage of the learning process. On the first training day, potentials appeared in the primary auditory, auditory association, prefrontal and premotor cortices of a naive monkey. The potentials of the auditory association, prefrontal and premotor cortices became less marked on the next and following days. After a few weeks of training, the potential of the auditory association cortex started to increase again, while the monkey still lifted the lever randomly. When the potential of the auditory association cortex grew to a certain extent, the monkey began to respond to the stimulus with the movement, and potentials appeared in the motor cortex in response to the auditory stimulus. After this process, the potentials in the auditory association and motor cortices gradually increased with further training, and the movement became shorter and less variable in reaction time. The potential in the motor cortex was shown to be mediated by the neocerebellum and superficial thalamo-cortical projection. The changes of potentials associated with the learning processes of audio-initiated movements were respectively compared with those of the learning processes of the visuo-initiated movement, reported previously (Sasaki and Gemba 1982), and cortical and subcortical mechanisms related to the learning process were discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell reports 18 (1998), S. 249-251 
    ISSN: 1432-203X
    Keywords: Key wordsAtropa belladonna ; Hairy root ; Littorine ; Root culture ; Tropane alkaloid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A hairy root clone (M8) of Atropa belladonna, producing high levels of tropane alkaloids, was established by transformation with Agrobacterium rhizogenes (MAFF 03-01724). Littorine, an intermediate of tropane alkaloids, was detected by high-performance liquid chromatography and gas chromatography-mass spectrometry in the alkaloid fraction of the hairy roots and identified by nuclear magnetic resonance analysis. Littorine was also detected in the non-transformed root culture of A. belladonna.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-203X
    Keywords: Key words Forskolin ; Coleus forskohlii ; Hairy root
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hairy roots of Coleus forskohlii were induced by infection with the Agrobacterium rhizogenes MAFF 03-01724 strain. Growth and forskolin production of two hairy root clones cultured in various liquid media were examined. Hairy root clone B9 grew well in woody plant liquid medium and showed a high forskolin yield (ca. 1.3 mg/ 100 ml flask) after 5 weeks of culture. The time course of growth and forskolin production of the clone B9 cultured in woody plant liquid medium was also examined. Rapid growth started at week 2 and continued until week 5. The highest forskolin yield (ca. 1.6 mg/100 ml flask) was obtained at week 5. Productivity was much higher than that previously reported.
    Type of Medium: Electronic Resource
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