Moreover, it should be noted that other interpretations of the functional role of ACC/dMPFC have been developed, such as error likelihood [48], [49], regret [50], action value [51], [52], response evaluation [53], and uncertainty [54], [55], [56].
In the striatum, dopamine is known to modulate synaptic plasticity [19] allowing for the activity of these neurons to encode action value [30].
Previous work has demonstrated that neural activity in the caudate nucleus is modulated by task-relevant action values [6, 8].
Functional MRI studies have demonstrated that the striatum is clearly involved in biasing action selection in accord with current action values [13], and that activity in this structure changes in accord with ongoing prediction errors [10], [31] [32].
Z-scored regression coefficients for left minus right action value at 300 ms (ordinate) are plotted against Z-scored regression coefficients for left minus right choice at 700 ms (abscissa), for each DLPFC neuron (R=0.42; p=3.6*10-14).
The directive -- issued last February and intended to protect all workers, orchestral musicians included -- specifies a daily "upper exposure action value" of 85 decibels, amid a welter of other provisions.
The effective learning rates were significantly correlated with the standard deviations of action values in 77 of 130 sessions, whereas they were correlated with the means in only 49 sessions.
Thus, we inferred that the rats took a model-free strategy (i.e. standard Q-learning or Bayesian Q-learning model) and analysed the changes in the choice and learning rate in terms of the uncertainty of action values (Figs 5 and 7C).
According to official epidemiologic data 1.2 million Germans are exposed to a daily vibration level greater than A 8)=2,5m/s (exposure action value in a 8 hours/day exposure), which does present a potential health risk [ 29].
In Figure 1C, we calculated the Z-statistic for action value difference at 300 ms and chosen action at 700 ms for each neuron from the regression model, and plotted the relationship between these Z-statistics across all DLPFC neurons.
As can be seen, variance in their firing is explained by the action value difference early (~200- 400 ms), and the chosen action late (~600 800 ms) in the decision process.
