Relating genetic variations in dopamine brain transmission to task performance with and without rewards

To evaluate potential genetic influences on learning in young people with
and without cerebral palsy (CP), we calculated individual dopamine-related
gene scores and compared these to the ability to learn two different
tasks, an implicit sequence learning task, the Serial Reaction Time Task
(SRTT) and a probabilistic classification task, the Weather Prediction
Task (WPT).  For the SRTT, 85% of trials had the same sequence
(i.e., probable) which should lead to implicit learning; 15% were a
different sequence (i.e., improbable), The SRTT was also administered in
an unrewarded condition and a rewarded one known to increase circulating
levels of dopamine, each consisting of 20 trials each.  Data are
presented for each block for 4 different outcomes (unrewarded probable
which is considered the baseline learning score; unrewarded improbable;
rewarded probable which indicates the effect of rewards on learning, and
rewarded improbable). There were two outcome measures for each set of
blocks: Reaction Time and Error Rate. For the WPT, the Feedback condition
(rewarded) had 150 training trials during which they received rewards for
accurate performance  Training for the Paired association
condition consisted of showing them the cards and the outcome for each of
the 150 trials. Then both the Feedback (FB) and the Paired Association
(PA) conditions had a test which was used for data analysis. Both the
proportion correct and reaction time were the outcome
measures.    Gene scores are presented
individually and in a summed gene score for each participant. All analyses
reported in the paper were performed using these data or values computed
from these data. The main analyses were to determine if learning occurred,
whether it differed by participant groups, or whether it was improved with
rewards.  Finally, the central hypothesis was tested which was on
the influences of gene scores on learning with and without
rewards.