Figure 2.

The effect of excitotoxic lesions of OFC on reward-guided behavior. A) Excitotoxic OFC lesions; location and extent of the intended lesion shown on drawing of a coronal section through the frontal lobe (Intended lesion, top), representative case with an excitotoxic lesion of OFC (T2-weighted MRI, taken 5 days after the injection of excitotoxins, middle), and representative case with an excitotoxic lesion of OFC (T1-weighted MRI, taken ~3 years after surgery, bottom). B) Serial object reversal learning. Mean (±SEM) number of errors for unoperated controls (CON_EXC and CON_ASP, unfilled circles and squares respectively), macaques with excitotoxic OFC lesions (OFC_EXC, shaded triangles) and macaques with aspiration lesions of OFC (OFC_ASP, shaded diamonds). Unlike monkeys with aspiration lesions of OFC, monkeys with excitotoxic lesions of OFC do not differ from controls in their performance on this task. C) Emotional responses to neutral and fear inducing objects. Mean (±SEM) latency of unoperated controls (unfilled bars) and monkeys with excitotoxic OFC lesions (gray bar) to retrieve a desired food reward in the presence of different objects. Monkeys with excitotoxic lesions of OFC do not differ from controls. D) Devaluation task. Mean (±SEM) difference scores for unoperated controls (unfilled bars) and macaques with excitotoxic lesions of OFC (gray bars) in the object-(left) and action-based (right) devaluation tasks. Same labels as in (C). Monkeys with excitotoxic lesions of OFC are still undergoing behavioral testing; the estimated extents of the OFC lesions as determined from postoperative T2-weighted MR scans ranged from 64 to 96% complete, and later T1-weighted (structural) MR scans are consistent with this picture. There was no correlation of the lesion extent and scores on any behavioral assessment. Adapted from Rudebeck et al. (2013b) and Rhodes and Murray (2013).