Figure 2.

A) Anatomical visualization of different memory-related regions, segmented into subregions supporting different memory subsystems (MSP = monosynaptic pathway; TSP = trisynaptic pathway; DMS = dorsomedial striatum; DLS = dorsolateral striatum; CeA = central amygdala; BLA = basolateral amygdala). B) Schematic of representations supported by memory subsystems associated with brain subregions in (A). Subsystems indicated in pink tend to support specific, rapidly formed, separated memory representations whereas subsystems indicated in yellow tend to support general, gradually formed, integrated memory representations. Top: the hippocampus forms associations among stimuli (circles). Episodic associations (left) bind together trial-unique stimuli (colored circles with unique symbols) into discrete episodes. Statistically learned associations (right) reflect the extraction of commonalities across experiences (e.g., the co-occurrence of the colored circles, abstracted away from idiosyncratic details). Middle: the striatum forms associations between stimuli (circles), responses (triangles), and outcomes (squares). Goal-directed associations (left) are sensitive to outcomes, whereas habits (right) reflect continuing to make responses when the stimulus is presented, even in the absence of a (desirable) outcome. Bottom: the amygdala forms associations between stimuli (circles) and outcomes (squares). Specific conditioning (left) reflects an association between a cue and an outcome (e.g., juice reward). General conditioning (right) reflects an association between a cue and a general motivational state (e.g., positive affect).