Proefschrift_Holstein

Reward modulation of cognitive function: the nucleus accumbens

Reward

High Low

4

2

Accuracy

a

improved performance

0 (correct > incorrect)

-2

Switch

Repeat

Switching

Figure 6.2 Task switching differences in the high versus low reward context A: For each reward context (high and low), the performance on switch and repeat trials is shown. The y axis represents the number of correct vs. incorrect lever presses (per minute), recorded during the first 10s of each trial. Error bars represent standard errors of the difference between correct and incorrect responses.

Results Discrimination training

A repeated measures GLM with the factor accuracy (correct vs. incorrect) confirmed that, by the end of training, animals were able to reliably discriminate between the two auditory stimuli (F(1,23) = 77.400, p < 0.001, η2 =0.771) and between the two visual stimuli (F(1,23) = 19..949, p < 0.001, η2 = 0.464; Table 6.3 ). Reliable discrimination between the correct and incorrect lever was achieved during day 2 of training on the auditory training and from day 8 onwards for the visual discrimination training ( Table 6.3 ). Reward context can alter task-switching performance Importantly, animals were able to use the task cue to successfully discriminate between the response-incongruent stimuli, which was reflected by a main effect of accuracy (correct vs. incorrect lever presses: (F(1,23) = 4.667, p = 0.041, η2 = 0.169). We did not observe a main effect of reward or of task-switching in terms of accuracy (F < 1). The reward context affected task-switching performance. More specifically, animals were better at switching between the auditory and visual modalities in each compound stimulus

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