Figure 4:

Four channels may convey acquired signals from the striatum to the lateral habenula, with Direct path inhibiting GPi (globus pallidus internal segment) while Indirect path via GPe (external segment) has a disinhibitory effect. The effect of GPi on LHb (lateral habenula) appears to be net excitatory, while LHb is net inhibitory on DA (VTA, SNc) via the RMTg (rostromedial tegmental nucleus). As shown, immediate firing from the Matrix pathway can drive appropriate phasic DA signaling (Direct = positive valence, Indirect = negative), while Patch has more delayed timing, with the timing becoming more precise via GP dynamics, such that the effect on LHb opposes the direct effect of USs (dotted lines, negative valence for the Direct pathway, positive for Indirect) – if the US does not occur, then DA responds as shown in the solid lines.