Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex.

Orbitofrontal cortex (OFC) is classically linked to inhibitory control, emotion regulation, and reward processing. Recent perspectives propose that the OFC also generates predictions about perceptual events, actions, and their outcomes. We tested the role of the OFC in detecting violations of prediction at two levels of abstraction (i.e., hierarchical predictive processing) by studying the event-related potentials (ERPs) of patients with focal OFC lesions (n = 12) and healthy controls (n = 14) while they detected deviant sequences of tones in a local-global paradigm. The structural regularities of the tones were controlled at two hierarchical levels by rules defined at a local (i.e., between tones within sequences) and at a global (i.e., between sequences) level. In OFC patients, ERPs elicited by standard tones were unaffected at both local and global levels compared to controls. However, patients showed an attenuated mismatch negativity (MMN) and P3a to local prediction violation, as well as a diminished MMN followed by a delayed P3a to the combined local and global level prediction violation. The subsequent P3b component to conditions involving violations of prediction at the level of global rules was preserved in the OFC group. Comparable effects were absent in patients with lesions restricted to the lateral PFC, which lends a degree of anatomical specificity to the altered predictive processing resulting from OFC lesion. Overall, the altered magnitudes and time courses of MMN/P3a responses after lesions to the OFC indicate that the neural correlates of detection of auditory regularity violation are impacted at two hierarchical levels of rule abstraction.

Posterior spine fusion in a Jehovah's Witness patient with severe rigid idiopathic scoliosis - A case report.

Introduction: Early onset scoliosis (EOS) represent a challenge for spine surgeons. The selection of the best treatment is complex. Some patients, such as Jehovah's Witnesses who refuse blood transfusions, are at high risk of complication when surgical treatment is required because blood loss is a major cause of morbidity and postoperative transfusion rates. Research question: Describe blood-saving techniques that allowed an extensive and invasive surgical procedure in a Jehovah's Witness patient. Material and method: 17-year-old Jehovah's Witness girl with severe 120° Cobb Lenke 1A idiopathic scoliosis started as EOS was prepared with 4 cycles of recombinant human erythropoietin, iron and folic acid supplementation that brought her hemoglobin level from 13.6 g/dl to 16.2 g/dl. In the first surgical time, a temporary rod was implanted. Spine dissection using bipolar sealer and a special electrocautery that operates at lower temperatures than traditional ones was performed. Facetectomies and multilevel Ponte osteotomies was performed using an ultrasonic bone scalpel. The second surgical time, the definitive rods were placed, and the correction of the deformity was achieved using the rod link reducer technique. Results: A good correction of the main curve in the coronal plane is achieve. The Hb nadir was 7.2 g/dl four days after the second operation. The postoperative course was uneventful. Discussion and conclusion: The integration of modern and traditional preoperative, intraoperative, and postoperative blood sparing techniques allowed us to perform an extensive and invasive surgical procedure in a Jehovah's Witness girl with a severe idiopathic scoliosis.

Management of Recurrent Meningiomas: State of the Art and Perspectives.

BACKGROUND: While meningiomas often recur over time, the natural history of repeated recurrences and their management are not well described. Should recurrence occur, repeat surgery and/or use of adjuvant therapeutic options may be necessary. Here, we summarize current practice when it comes to meningioma recurrence after initial surgical management. METHODS: A total of N = 89 articles were screened. N = 41 articles met the inclusion criteria and N = 16 articles failed to assess management of meningioma recurrence. Finally, N = 24 articles were included in our review. RESULTS: The articles were distributed as follows: studies on chemotherapy (N = 14), radiotherapy, protontherapy, and stereotaxic radiosurgery (N = 6), boron-neutron capture therapy (N = 2) and surgery (N = 3). No study seems to provide serious alternatives to surgery in terms of progression-free and overall survival. Recurrence can occur long after the initial surgery and also affects WHO grade 1 meningiomas, even after initial gross total resection at first surgery, emphasizing the need for a long-term and comprehensive follow-up. CONCLUSIONS: Surgery still seems to be the state-of-the-art management when it comes to meningioma recurrence, since none of the non-surgical alternatives show promising results in terms of progression-free and overall survival.

Contribution of subregions of human frontal cortex to novelty processing.

Novelty processing was studied in patients with lesions centered in either OFC or lateral pFC (LPFC). An auditory novelty oddball ERP paradigm was applied with environmental sounds serving as task irrelevant novel stimuli. Lesions to the LPFC as well as the OFC resulted in a reduction of the frontal Novelty P3 response, supporting a key role of both frontal subdivisions in novelty processing. The posterior P3b to target sounds was unaffected in patients with frontal lobe lesions in either location, indicating intact posterior cortical target detection mechanisms. LPFC patients displayed an enhanced sustained negative slow wave (NSW) to novel sounds not observed in OFC patients, indicating prolonged resource allocation to task-irrelevant stimuli after LPFC damage. Both patient groups displayed an enhanced NSW to targets relative to controls. However, there was no difference in behavior between patients and controls suggesting that the enhanced NSW to targets may index an increased resource allocation to response requirements enabling comparable performance in the frontal lesioned patients. The current findings indicate that the LPFC and OFC have partly shared and partly differential contributions to the cognitive subcomponents of novelty processing.