Table 1.

Hypothesized factors affecting fMRI tasks

Factor	FIX	CONrew	SWITCH	REDrew
Anticipation	x	x	x	x
Target detection		x	x	x
Constant reward		x	x	x
Motor response		x	XX	XX
Novelty detection			x	x
Reduced reward				XX
Error detection*

Factors hypothesized to affect fMRI responses (first column) have established single-neuron representations from monkey studies. The x marks indicate a hypothesized contribution to the condition above. The presence of XX denotes a particularly large hypothesized influence (i.e., much more processing is needed to overcome a prepotent motor output tendency in SWITCH and REDrew trials, and REDrew-specific cells represent 37% of dACC cells; ref. 27). Error detection units, though part of the model, are indicated here with an asterisk, as the current study could not assess this (because error rates were equivalent among the three tasks).