Value-guided remapping of sensory cortex by lateral orbitofrontal cortex.

Adaptive behaviour crucially depends on flexible decision-making, which in mammals relies on the frontal cortex, specifically the orbitofrontal cortex (OFC)1-9. How OFC encodes decision variables and instructs sensory areas to guide adaptive behaviour are key open questions. Here we developed a reversal learning task for head-fixed mice, monitored the activity of neurons of the lateral OFC using two-photon calcium imaging and investigated how OFC dynamically interacts with primary somatosensory cortex (S1). Mice learned to discriminate 'go' from 'no-go' tactile stimuli10,11 and adapt their behaviour upon reversal of stimulus-reward contingency ('rule switch'). Imaging individual neurons longitudinally across all behavioural phases revealed a distinct engagement of S1 and lateral OFC, with S1 neural activity reflecting initial task learning, whereas lateral OFC neurons responded saliently and transiently to the rule switch. We identified direct long-range projections from lateral OFC to S1 that can feed this activity back to S1 as value prediction error. This top-down signal updated sensory representations in S1 by functionally remapping responses in a subpopulation of neurons that was sensitive to reward history. Functional remapping crucially depended on top-down feedback as chemogenetic silencing of lateral OFC neurons disrupted reversal learning, as well as plasticity in S1. The dynamic interaction of lateral OFC with sensory cortex thus implements computations critical for value prediction that are history dependent and error based, providing plasticity essential for flexible decision-making.

Hyperbaric oxygen for idiopathic sudden hearing loss: is the routine application helpful?

CONCLUSION: We recommend the routine application of hyperbaric oxygen (HBO) in conjunction with intravenous steroid (IVS) for all patients with idiopathic sudden sensorineural hearing loss (ISSNHL). For best results, this therapy must be started within 14 days. OBJECTIVE: To investigate the necessity of routine application of HBO therapy for ISSNHL. METHODS: This was a retrospective cohort study. A total of 300 patients (300 diseased ears) were divided into 3 groups according to the therapy received: IVS (group A), HBO (group B), or IVS + HBO (group C). Patients in each treatment group were subdivided into subgroups according to the time of therapy initiation. The outcomes of their hearing recovery were classified into three recovery grades: good, fair, and poor. RESULTS: The proportion of patients responding to therapy and those with complete recovery was the highest in the combined treatment group, 84% and 58%, respectively, regardless of the initial hearing levels. In all the groups, mean gains of cases in whom therapy was started in the first 2 weeks were significantly higher (p < 0.05) and hypercholesterolemia (>240 mg/dl) caused significantly worse responses (p < 0.05).

Underwater acoustic sensors based on fiber bragg gratings.

We report on recent results obtained with a fiber optic hydrophone based on the intensity modulation of the laser light in a FBG (Fiber Bragg Grating) under the influence of the sound pressure. In order to control the behavior of the hydrophone in terms of sensitivity and bandwidth, FBGs have been coated with proper materials, characterized by different elastic modulus and shapes. In particular, new experiments have been carried out using a cylindrical geometry with two different coating, showing that the sensitivity is not influenced by the shape but by the transversal dimension and the material characteristics of the coating.

Osteosarcoma of the larynx: a case report.

BACKGROUND: We add a new rare illustrative case of osteosarcoma of the larynx to the literature. CASE PRESENTATION: The patient (man; 56 years old) first underwent several biopsies, followed in the end by a total laryngectomy. Diagnosis was histological. The patient developed regional and distant metastases and died of disease after 3 months from surgery. CONCLUSION: Osteosarcoma of the larynx is a rare and aggressive tumour with a poor long-term prognosis. The preferred treatment for this tumour is aggressive surgery.To perform a diagnosis we must be in presence of osteoid or of neoplastic osseous tissue directly produced by the neoplastic cells.