Figure 2.

Performance in the (A) cognitive and (B) physical effort tasks (mean ± 1 SEM). (A) In the cognitive effort task, decrements in target detection sensitivity (left) and reinforcement rates (right) with increasing effort were more pronounced in the Huntington’s disease (HD) group (in blue) than controls (in black). (B) A similar pattern of results was found in the physical effort task. The proportion of time participants were able to maintain their force above the target level decreased with effort (left) and this decrement was steeper in the HD group (in red) than controls (in black). This was reflected in the reinforcement rates of each group (right). SEM = standard error of the mean.