| 1. |
- 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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| 2. |
- Jörntell, Henrik, et al.
(författare)
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Segregation of tactile input features in neurons of the cuneate nucleus.
- 2014
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Ingår i: Neuron. - : Elsevier BV. - 0896-6273. ; 83:6, s. 1444-1452
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Tidskriftsartikel (refereegranskat)abstract
- Our tactile perception of external objects depends on skin-object interactions. The mechanics of contact dictates the existence of fundamental spatiotemporal input features-contact initiation and cessation, slip, and rolling contact-that originate from the fact that solid objects do not interpenetrate. However, it is unknown whether these features are represented within the brain. We used a novel haptic interface to deliver such inputs to the glabrous skin of finger/digit pads and recorded from neurons of the cuneate nucleus (the brain's first level of tactile processing) in the cat. Surprisingly, despite having similar receptive fields and response properties, each cuneate neuron responded to a unique combination of these inputs. Hence, distinct haptic input features are encoded already at subcortical processing stages. This organization maps skin-object interactions into rich representations provided to higher cortical levels and may call for a re-evaluation of our current understanding of the brain's somatosensory systems.
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| 3. |
- Jörntell, Henrik, et al.
(författare)
-
Synaptic memories upside down: bidirectional plasticity at cerebellar parallel fiber-purkinje cell synapses.
- 2006
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Ingår i: Neuron. - : Elsevier BV. - 0896-6273. ; 52:2, s. 227-238
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Forskningsöversikt (refereegranskat)abstract
- Information storage in neural circuits depends on activity-dependent alterations in synaptic weights, such as long-term potentiation (LTP) and long-term depression (LTD). Bidirectional synaptic plasticity endows synapses with mechanisms for rapid reversibility, but it remains unclear how it correlates with reversibility in behavioral learning and whether there is a universal synaptic memory mechanism that operates similarly at all types of synapses. A recently discovered postsynaptic form of LTP at cerebellar parallel fiber (PF)-Purkinje cell (PC) synapses provides a reversal mechanism for PF-LTD and enables a fresh look at the implications of bidirectional plasticity in a brain structure that is particularly suitable to correlate cellular to behavioral learning events. Here, we will review recent studies that reveal unique properties of bidirectional cerebellar plasticity and suggest that the induction cascades for cerebellar LTP and LTD provide a mirror image of their counterparts at hippocampal synapses. We will also discuss how PF-LTP helps to explain reversibility observed in cerebellar motor learning.
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