A model of working memory for encoding multiple items and ordered sequences exploiting the theta-gamma code

Recent experimental evidence suggests that oscillatory activity plays a pivotal role in the maintenance of information in working memory, both in rodents and humans. In particular, cross-frequency coupling between theta and gamma oscillations has been suggested as a core mechanism for multi-item memory. The aim of this work is to present an original neural network model, based on oscillating neural masses, to investigate mechanisms at the basis of working memory in different conditions. We show that this model, with different synapse values, can be used to address different problems, such as the reconstruction of an item from partial information, the maintenance of multiple items simultaneously in memory, without any sequential order, and the reconstruction of an ordered sequence starting from an initial cue. The model consists of four interconnected layers; synapses are trained using Hebbian and anti-Hebbian mechanisms, in order to synchronize features in the same items, and desynchronize features in different items. Simulations show that the trained network is able to desynchronize up to nine items without a fixed order using the gamma rhythm. Moreover, the network can replicate a sequence of items using a gamma rhythm nested inside a theta rhythm. The reduction in some parameters, mainly concerning the strength of GABAergic synapses, induce memory alterations which mimic neurological deficits. Finally, the network, isolated from the external environment ("imagination phase") and stimulated with high uniform noise, can randomly recover sequences previously learned, and link them together by exploiting the similarity among items

Confocal Laser Scanning Microscopy Applied to a New Species Helps Understand the Functioning of the Reproductive Apparatus in Stylet-Bearing Urodasys (Gastrotricha: Macrodasyida)

Gastrotrichs are highly diverse and abundant in all aquatic ecosystems; however, they are often overlooked. During a biodiversity survey in Sardinia (Italy), a new species of gastrotrich herein described was discovered. Specimens of Urodasys bifidostylis sp. nov. were found in sandy sediments from two submarine caves. Using an integrative approach of traditional light (DIC) and high-resolution (CLSM) microscopies, we herein reveal, for the first time, the fine structure and function of the reproductive organ in an Urodasys representative. This is particularly relevant considering the complex reproductive organs and strategies of this group. Results allow comparisons between the reproductive apparatus and sperm transfer modalities in Urodasys and the closely related genus Macrodasys. One similarity is that both groups transfer male gametes in packets, suggesting the production of spermatophores to be a common phenomenon in Gastrotricha. Unique to Urodasys is the ability of multiple and consecutive copulations and sperm transfers and, differently than Macrodasys, the transfer of sperms unlikely occurs simultaneously between the two hermaphroditic partners. These findings provide new insights into the reproductive strategies of Urodasys and are expected to advance future studies on the evolution of reproductive strategies and the rise of interspecific reproductive barriers in interstitial meiofauna

Epidemiological overview of Hodgkin lymphoma across the Mediterranean Basin

The epidemiology of Hodgkin lymphoma (HL) has always been a source of fascination to researchers due to its heterogeneous characteristics of presentation. HL is an uncommon neoplasm of B-cell origin with an incidence that varies significantly by age, sex, ethnicity, geographic location and socioeconomic status. This complex pattern was also found to be replicated among Mediterranean basin populations. HL incidence rates progressively decreased from industrialized European countries such as France (ASR=2.61) and Italy (ASR=2.39) to less developed nations such as Albania (ASR=1.34) and Bosnia Herzegovina (ASR=1.1). Regarding HL mortality we have found that countries with the lowest incidence rates show the highest number of deaths from this cancer and viceversa. Finally, a wide gap in terms of survival was showed across the Mediterranean basin with survival rates ranged from 82.3% and 85.1% among Italian men and women, to 53.3 % and 59.3% among Libyan men and women, respectively. Factors such as the degree of socio-economic development, the exposure to risk factors westernization-related, the availability of diagnostic practices along with different genetic susceptibilities to HL may explain its variation across Mediterranean countries. Furthermore, the lack of health resources decisively contribute to the poor prognosis recorded in less developed region. In the future, the introduction of appropriate and accessible treatment facilities along with an adequate number of clinical specialists in the treatment of HL and other cancers are warranted in order to improve the outcomes of affected patients and treat a largely curable type of cancer in disadvantaged regions

Implementation and Assessment Methodologies of Teachers' Training Courses for STEM Activities

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Decreasing incidence of gastric MALT lymphomas in the era of anti-Helicobacter pylori interventions: results from a population-based study on extranodal marginal zone lymphomas

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Intraoperatively malpositioned stent as a complication of common bile duct injury during laparoscopic cholecystectomy

Injuries occurring during laparoscopic bile duct exploration in the course of laparoscopic cholecystectomy may represent threatening complications and lead to inappropriate management. We present a case of patient with biliary colic who underwent laparoscopic cholecystectomy. During the procedure, a common bile duct injury occurred, compelling conversion to open approach, and the patient was treated using a manually inserted biliary stent. She was referred with severe right upper quadrant pain six weeks after the surgery. Investigation with endoscopic retrograde cholangiopancreatography showed a malpositioned biliary stent with completely extra-biliary trajectory. This is thought to be the first description of a malpositioned common bile duct stent through the common biliary duct as a complication of the commonly performed surgical procedure of bile duct exploration

Diagnostic Value of Prenatal MR Imaging in the Detection of Brain Malformations in Fetuses before the 26th Week of Gestational Age

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From deceased to bioengineered graft: New frontiers in liver transplantation

none6siopenCesaretti M.; Zarzavajian Le Bian A.; Moccia S.; Iannelli A.; Schiavo L.; Diaspro A.Cesaretti, M.; Zarzavajian Le Bian, A.; Moccia, S.; Iannelli, A.; Schiavo, L.; Diaspro, A

Variability of Forebrain Commissures in Callosal Agenesis: A Prenatal MR Imaging Study

BACKGROUND AND PURPOSE: Agenesis of the corpus callosum, even when isolated, may be characterized by anatomic variability. The aim of this study was to describe the types of other forebrain commissures in a large cohort of randomly enrolled fetuses with apparently isolated agenesis of the corpus callosum at prenatal MR imaging. MATERIALS AND METHODS: All fetuses with apparent isolated agenesis of the corpus callosum undergoing prenatal MR imaging from 2004 to 2014, were evaluated for the presence of the anterior or a vestigial hippocampal commissure assessed in consensus by 2 pediatric neuroradiologists. RESULTS: Overall, 62 cases of agenesis of the corpus callosum were retrieved from our data base. In 3/62 fetuses (4.8%), no forebrain commissure was visible at prenatal MR imaging, 23/62 fetuses (37.1%) presented with only the anterior commissure, and 20/62 fetuses (32.3%) showed both the anterior commissure and a residual vestigial hippocampal commissure, whereas in the remaining 16/62 fetuses (25.8%), a hybrid structure merging a residual vestigial hippocampal commissure and a rudiment of the corpus callosum body was detectable. Postnatal MR imaging, when available, confirmed prenatal forebrain commissure findings. CONCLUSIONS: Most fetuses with apparent isolated agenesis of the corpus callosum showed at least 1 forebrain commissure at prenatal MR imaging, and approximately half of fetuses also had a second commissure: a vestigial hippocampal commissure or a hybrid made of a hippocampal commissure and a rudimentary corpus callosum body. Whether such variability is the result of different genotypes and whether it may have any impact on the long-term neurodevelopmental outcome remains to be assessed. AC : anterior commissure ACC : agenesis of the corpus callosum CC : corpus callosum GA : gestational age HC : hippocampal commissure HS : hybrid structur