the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
medial prefrontal cortical ( mpfc ) functions may be aspects of ventral or dorsal control pathways , depending on the position along a rostral  ventral to caudal 
 dorsal gradient within medial cortex that may mirror the pattern of interconnections between cortex and striatum . 
 rostral 
 ventral mpfc is connected to ventral striatum and posterior cingulate cortex / precuneus are connected with dorsal striatum . 
 reentrant ventral ( limbic ) , central ( associative ) , and dorsal ( motor ) corticostriatal loops pass information from ventral - to - dorsal striatum , shifting hedonic processing toward habitual action . 
 splitting up unexpected occurrences ( positive surprise ) from non - occurrences ( negative surprise ) instead of splitting according to valence mirrors the importance of negative surprise in dorsal habitual control which is insensitive to the valence of outcomes . 
 the importance of positive surprise and valence increases toward the rostral  ventral end of the gradient in mpfc and ventrolateral prefrontal cortex . 
 we discuss paradigms that may help to disentangle positive from negative surprise . 
 moreover , we think that the framework of the functional gradient may help giving various functions in mpfc their place in a larger scheme .