Classical blink conditioning is known to depend critically on the cerebellum and the relevant circuitry is gradually being unravelled. Several lines of evidence support the theory that the conditioned stimulus is transmitted by mossy fibers to the cerebellar cortex whereas the unconditioned stimulus is transmitted by climbing fibers. This view has been dramatically confirmed by recent Purkinje cell recordings during training with a classical conditioning paradigm. We have tracked the activity of single Purkinje cells with microelectrodes for several hours in decerebrate ferrets during learning, extinction, and relearning. Paired peripheral forelimb and periocular stimulation, as well as paired direct stimulation of cerebellar afferent pathways (mossy and climbing fibers) causes acquisition of a pause response in Purkinje cell simple spike firing. This conditioned Purkinje cell response has temporal properties that match those of the behavioral response. Its latency varies with the interstimulus interval and it responds to manipulations of the conditioned stimulus in the same way that the blink does. Complex spike firing largely mirrors the simple spike behavior. We have previously suggested that cerebellar learning is subject to a negative feedback control via the inhibitory nucleo-olivary pathway. As the Purkinje cell learns to respond to the conditioned stimulus with a suppression of simple spikes, disinhibition of anterior interpositus neurons would be expected to cause inhibition of the inferior olive. Observations of complex spike firing in the Purkinje cells during conditioning and extinction confirm this prediction. Before training, complex spikes are unaffected or facilitated by the conditioned stimulus, but as the simple spike pause response develops, spontaneous and stimulus-evoked complex spikes are also strongly suppressed by the conditioned stimulus. After extinction of the simple spike pause response, the complex spikes reappear.
|State||Published - 2008|
Eva Sjöstrand, Ingela Byström, Magnus Lindgren, Johan Mårtensson, Annika Andersson, Birgitta Sahlén, Kristina Hansson, Marianne Gullberg, Roger Johansson, Mikael Johansson, Andreas Falck, Mikael Roll, Freddy Ståhlberg, Merle Horne, Frida Blomberg, Victoria Johansson, Sven Strömqvist, Jens Nirme, Agneta Gulz, Joost van de Weijer, Carita Paradis, Betty Tärning, Ines Bramao, Susan Sayehli, Simone Löhndorf, Caroline Willners, Johan Blomberg, Susanne Schötz, Magnus Haake, Jonas Brännström, Emily Grenner, Peter Gärdenfors, Jana Holsanova, Åsa Wengelin, Magnus Johnsson, Stefan Winberg, Christian Balkenius, Zahra Gharaee & Rasmus Bååth
Swedish Research Council
2008/01/01 → 2018/12/31
Project: Research › Interdisciplinary research
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