Detailed components of PVLV, showing the opponent processing pathways
within the PV and LV systems, which separately encode the strength of support
for and against each US, and with opposite dynamics for appetitive versus
aversive valence. BLA has pathways for appetitive and aversive USs, along with
distinctions between acquisition and extinction learning, all of which engage in
broad inhibitory competition. The BLA projects to central amygdala (CEl, CEm)
neurons that integrate the evidence for-and-against a given US, and communicate
this net value to the VTA (and SNc, not shown). The ventral striatum (VS) has
matrix and patch subsystems, where matrix (VSm) receives modulatory inputs from
corresponding BLA neurons and represents CSs in a phasic manner, and patch (VSp)
anticipates and cancels USs. Both have a full complement of opposing D1- and
D2-dominant pathways, which have opposing effects for appetitive versus aversive
USs.