| 1. |
- Ekerot, Carl-Fredrik, et al.
(författare)
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Parallel fiber receptive fields: a key to understanding cerebellar operation and learning.
- 2003
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Ingår i: Cerebellum. - : Springer Science and Business Media LLC. - 1473-4230. ; 2:2, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- In several theories of the function of the cerebellum in motor control, the mossy-fiber-parallel fiber input has been suggested to provide information used in the control of ongoing movements whereas the role of climbing fibers is to induce plastic changes of parallel fiber (PF) synapses on Purkinje cells. From studies of climbing fibers during the last few decades, we have gained detailed knowledge about the zonal and microzonal organization of the cerebellar cortex and the information carried by climbing fibers. However, properties of the PF input to Purkinje cells and inhibitory interneurones have been largely unknown. The present review, which focuses on the C3 zone of the cerebellar anterior lobe, will present and discuss recent data of the cutaneous PF input to Purkinje cells, interneurons and Golgi cells as well as novel forms of PF plasticity
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| 2. |
- Jörntell, Henrik, et al.
(författare)
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Functional organization of climbing fibre projection to the cerebellar anterior lobe of the rat
- 2000
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Ingår i: Journal of Physiology. - 1469-7793. ; 522:2, s. 297-309
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Tidskriftsartikel (refereegranskat)abstract
- 1. The input characteristics and distribution of climbing fibre field potentials evoked by electrical stimulation of various parts of the skin were investigated in the cerebellum of barbiturate anaesthetized rats. 2. Climbing fibre responses were recorded in sagittally oriented microelectrode tracks across the mediolateral width of the anterior lobe. Climbing fibres with similar response latencies and convergence patterns terminated in sagittal bands with widths of 0.5-1.5 mm. The principal organization of the anterior lobe with respect to input characteristics and locations of sagittal zones was similar to that in the cat and ferret. Hence, the sagittal bands in the rat were tentatively named the a, b, c1, c2 and d1 zones. 3. In contrast to the cat and ferret, the a zone of the rat was characterized by short latency ipsilateral climbing fibre input. Furthermore, it was divisible into a medial 'a1' zone with convergent, proximal input and a lateral 'ax' zone with somatotopically organized input. A forelimb area with similar location and input characteristics as the X zone of the cat was found, but it formed an integral part of the ax zone. A somatotopic organization of ipsilateral, short latency climbing fibre input was also found in the c1 zone. 4. Rostrally in the anterior lobe, climbing fibres activated at short latencies from the ipsilateral side of the body terminated in a somatotopically organized transverse band which extended from the midline to the lateral end of the anterior lobe. 5. The absence of the C3 and Y zones may be interpreted as a reflection of differences in the organization of the motor systems in the rat as compared with the cat. 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.
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| 3. |
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| 4. |
- Jörntell, Henrik, et al.
(författare)
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Receptive field plasticity profoundly alters the cutaneous parallel fiber synaptic input to cerebellar interneurons in vivo
- 2003
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Ingår i: The Journal of Neuroscience. - 1529-2401. ; 23:29, s. 9620-9631
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Tidskriftsartikel (refereegranskat)abstract
- The cutaneous parallel fiber (PF) receptive fields of cerebellar stellate and basket cells in the cerebellar C3 zone in vivo are normally very small but can be dramatically enlarged by climbing fiber (CF)-dependent plasticity. To analyze the effects of this receptive field plasticity, we present for the first time whole-cell patch-clamp recordings from these interneurons during natural and electrical activation of cutaneously driven synaptic input. In "naive" interneurons, peripheral input nearly exclusively activated a few (two to eight) large PF EPSPs from a specific small skin area that overlapped the receptive field of the local CF input. After conjunctive PF and CF stimulation, numerous small and large EPSPs and ramp-like depolarizations could be activated from the entire forelimb skin. These findings therefore confirm previous suggestions that conjunctive PF and CF activation leads to a long-lasting potentiation of PF synaptic input to interneurons. The CF response, which is crucial for the induction of the PF synaptic potentiation, was strong but variable and very different from the conventional EPSPs evoked by PFs.
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| 5. |
- Jörntell, Henrik, et al.
(författare)
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Reciprocal bidirectional plasticity of parallel fiber receptive fields in cerebellar Purkinje cells and their afferent interneurons.
- 2002
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Ingår i: Neuron. - 0896-6273. ; 34:5, s. 797-806
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Tidskriftsartikel (refereegranskat)abstract
- The highly specific relationships between parallel fiber (PF) and climbing fiber (CF) receptive fields in Purkinje cells and interneurons suggest that normal PF receptive fields are established by CF-specific plasticity. To test this idea, we used PF stimulation that was either paired or unpaired with CF activity. Conspicuously, unpaired PF stimulation that induced long-lasting, very large increases in the receptive field sizes of Purkinje cells induced long-lasting decreases in receptive field sizes of their afferent interneurons. In contrast, PF stimulation paired with CF activity that induced long-lasting decreases in the receptive fields of Purkinje cells induced long-lasting, large increases in the receptive fields of interneurons. These properties, and the fact the mossy fiber receptive fields were unchanged, suggest that the receptive field changes were due to bidirectional PF synaptic plasticity in Purkinje cells and interneurons.
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