Figure 3.

Over-activation and inactivation of area 25 in marmoset has largely opposing effects on tests measuring the regulation of responsivity to rewarding and punishing stimuli. Top from left. Over-activation via presynaptic glutamatergic disinhibition increased the bias away from punishment in an approach-avoidance decision making paradigm [140], and over-activation via inhibition of the excitatory glutamate amino acid transporter (EAAT2; with dihydrokainic acid [DHK]) increased anxiety-like behavior in the human intruder paradigm, increased the break point in a progressive ratio task, left sucrose consumption unaltered, and blunted the anticipation of food reward during appetitive conditioning [141]. Bottom from left. In contrast, inactivation with GABA A and B agonists (muscimol and baclofen) decreased the avoidance of punishment during approach-avoidance decision making [140] and reversed the blunted cardiovascular responsivity to threat in high trait anxious animals [46]. Inactivation also blunted the threat-induced anticipatory increases in heart rate and vigilant scanning (not shown) during Pavlovian threat conditioning and enhanced the rate of threat extinction [38], but had no effect on reward anticipation during appetitive conditioning [141]. *, p < 0.05, ^†, p < 0.05, main effect of manipulation; error bars indicate SEM. Thus, in general, over-activation blunted appetitive responses whilst enhancing threat-induced responses whilst inactivation primarily dampened threat-induced responses.