TY  - JOUR
AU  - Trempler, Ima
AU  - Bürkner, Paul-Christian
AU  - El-Sourani, Nadiya
AU  - Binder, Ellen
AU  - Reker, Paul
AU  - Fink, Gereon R.
AU  - Schubotz, Ricarda I.
TI  - Impaired context-sensitive adjustment of behaviour in Parkinson’s disease patients tested on and off medication: An fMRI study
JO  - NeuroImage
VL  - 212
SN  - 1053-8119
CY  - Orlando, Fla.
PB  - Academic Press
M1  - FZJ-2020-01711
SP  - 116674 -
PY  - 2020
AB  - The brain’s sensitivity to and accentuation of unpredicted over predicted sensory signals plays a fundamental role in learning. According to recent theoretical models of the predictive coding framework, dopamine is responsible for balancing the interplay between bottom-up input and top-down predictions by controlling the precision of surprise signals that guide learning.Using functional MRI, we investigated whether patients with Parkinson’s disease (PD) show impaired learning from prediction errors requiring either adaptation or stabilisation of current predictions. Moreover, we were interested in whether deficits in learning over a specific time scale would be accompanied by altered surprise responses in dopamine-related brain structures. To this end, twenty-one PD patients tested on and off dopaminergic medication and twenty-one healthy controls performed a digit prediction paradigm. During the task, violations of sequence-based predictions either signalled the need to update or to stabilise the current prediction and, thus, to react to them or ignore them, respectively. To investigate contextual adaptation to prediction errors, the probability (or its inverse, surprise) of the violations fluctuated across the experiment.When the probability of prediction errors over a specific time scale increased, healthy controls but not PD patients off medication became more flexible, i.e., error rates at violations requiring a motor response decreased in controls but increased in patients. On the neural level, this learning deficit in patients was accompanied by reduced signalling in the substantia nigra and the caudate nucleus. In contrast, differences between the groups regarding the probabilistic modulation of behaviour and neural responses were much less pronounced at prediction errors requiring only stabilisation but no adaptation. Interestingly, dopaminergic medication could neither improve learning from prediction errors nor restore the physiological, neurotypical pattern.Our findings point to a pivotal role of dysfunctions of the substantia nigra and caudate nucleus in deficits in learning from flexibility-demanding prediction errors in PD. Moreover, the data witness poor effects of dopaminergic medication on learning in PD.
LB  - PUB:(DE-HGF)16
C6  - pmid:32097724
UR  - <Go to ISI:>//WOS:000525320500014
DO  - DOI:10.1016/j.neuroimage.2020.116674
UR  - https://juser.fz-juelich.de/record/874939
ER  -