Klassische Konditionierung posturaler Reaktionen beim Menschen, unter Einbeziehung der Kleinhirnfunktion

The aim of the current study was to examine whether postural
reactions following externally triggered pertubations of the body
equilibrium can be modified due to a motor learning process. By
using the classical conditioning paradigm a ramp-shaped movement,
elicited by a dynamic platform, represented the unconditioned
stimulus (US) and a preceeding auditory information the
conditioning stimulus (CS). To modify spinal postural reflexes
supraspinal structures have to be involved. Subjects used the
information given by the CS in a completely different manner. Two
classes of response-patterns were observed, which were assumed to
be based on different strategies. For the strategy I an associative
process for strategy II a primarily non-associative process was
assumed. Nowadays the cerebellum is accepted to be substantially
involved in associative and non-associative processes. A patient,
suffering from an almost unilateral circumscript lesion in the
intermediate part of the left cerebellar anterior lobe resulting
from a tumor exstirpation, was examined with our paradigm. From the
findings it can be concluded that the cerebellum is substantially
involved in plastic processes. This is also coherent with the
clinically based functional compartimentation of the cerebellum
which postulates the intermediate parts of the cerebellum to be
involved in associative learning processes.