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We aimed to investigate whether novel stimulus relations would emerge from stimulus correlations when those relations explicitly conflicted with reinforced relations. In a symbolic matching-to-sample task using kanji characters as stimuli, we arranged class-specific incorrect comparison stimuli in each of three classes. After presenting either Ax or Cx stimuli as samples, choices of Bx were reinforced and choices of Gx or Hx were not. Tests for symmetry, and combined symmetry and transitivity, showed the emergence of three 3-member (AxBxCx) stimulus classes in 5 of 5 human participants. Subsequent tests for all possible emergent relations between Ax, Bx, Cx and the class-specific incorrect comparisons Gx and Hx showed that these relations emerged for 4 of 5 the participants after extended overtraining of the baseline relations. These emergent relations must have been based on stimulus-stimulus correlations, and were not properties of the trained discriminated operants, because they required control by relations explicitly extinguished during training. This result supports theoretical accounts of emergent relations that emphasize stimulus correlation over operant contingencies. (Contains 6 figures.)

Aim: Major depressive disorder (MDD) poses a significant and growing burden on the New Zealand population. It is a leading cause of disability, and resistance to currently offered treatments is common. Repetitive transcranial magnetic stimulation (rTMS) is a treatment offered internationally demonstrating good efficacy and few reports of side effects. It is an intervention that requires daily visits to a clinic over a period of at least four weeks. This study aimed to investigate the effectiveness and acceptability of offering rTMS as a treatment for MDD in the setting of New Zealand healthcare systems., Method: This was a naturalistic, open-label pilot study in which 30 patients with moderate-to-severe treatment-resistant MDD were treated with a course of rTMS (10 Hz) daily over the left dorsolateral prefrontal cortex for four weeks (20 sessions). Primary endpoint was response to treatment, stratified into non-responder, partial responder or responder based on the Montgomery-Åsberg Depression Rating Scale (MADRS) at the end of treatment compared to baseline (<25% reduction, 25-50% reduction, and >50% reduction respectively). Participant remission was also noted as reaching a score of ≤10., Results: Thirty participants completed the full course of treatment (16 women, mean age 47y, range 19-77y), with a mean baseline MADRS of 32.0 (range 21-48). Twelve participants were classified as responders, six as partial responders, and 12 as non-responders. Of the responders, nine were in remission at the end of treatment. Minimal side effects were reported., Conclusion: Daily sessions of rTMS were successfully administered and were effective in treatment-resistant MDD. The treatment was accessible and well tolerated by the majority of the study participants and should be made available to MDD patients in New Zealand as a treatment option., Competing Interests: All authors report grants from Oakley Mental Health Research Foundation during the conduct of the study.