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The aims of this project were to evaluate whether early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion resulted in any psychosocial benefits. This multicenter trial was carried out in the United Kingdom, with 174 children aged 8 to 10 years with Class II Division 1 malocclusions randomly allocated to receive treatment with Twin-block appliances or to an untreated control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in an increase in self-concept and a reduction of negative social experiences. The subjects also reported treatment benefits that could be related to improved self-esteem. Further research is needed to determine the extent to which these effects translate into social behavior and experiences.

Emerging human, animal, and computational evidence suggest that, within the hippocampus, stored memories are compared with current sensory input to compute novelty, i.e., detecting when inputs deviate from expectations. Hippocampal subfield CA1 is thought to detect mismatches between past and present, and detected novelty is thought to modulate encoding processes, providing a mechanism for gating the entry of information into memory. Using high-resolution functional MRI, we examined human hippocampal subfield and medial temporal lobe cortical activation during prediction violations within a sequence of events unfolding over time. Subjects encountered sequences of four visual stimuli that were then reencountered in the same temporal order (Repeat) or a rearranged order (Violation). Prediction strength was manipulated by varying whether the sequence was initially presented once (Weak) or thrice (Strong) prior to the critical Repeat or Violation sequence. Analyses of blood oxygen level-dependent signals revealed that task-responsive voxels in anatomically defined CA1, CA23/dentate gyrus, and perirhinal cortex were more active when expectations were violated than when confirmed. Additionally, stronger prediction violations elicited greater activity than weaker violations in CA1, and CA1 contained the greatest proportion of voxels displaying this prediction violation pattern relative to other medial temporal lobe regions. Finally, a memory test with a separate group of subjects showed that subsequent recognition memory was superior for items that had appeared in prediction violation trials than in prediction confirmation trials. These findings indicate that CA1 responds to temporal order prediction violations, and that this response is modulated by prediction strength.