Epidemiological and Clinical Aspects of Cutaneous and Mucosal Leishmaniases in Portugal: Retrospective Analysis of Cases Diagnosed in Public Hospitals and Reported in the Literature between 2010 and 2020.

Leishmania infantum, a zoonotic vector-born parasite, is endemic in the Mediterranean region, presenting mostly as visceral (VL), but also as cutaneous (CL) and mucosal leishmaniasis (ML). This study aimed to describe the epidemiological and clinical aspects of the CL and ML cases diagnosed in mainland Portugal between 2010 and 2020. Collaboration was requested from every hospital of the Portuguese National Health System. Cases were screened through a search of diagnostic discharge codes or positive laboratory results for Leishmania infection. Simultaneously, a comprehensive literature search was performed. Descriptive statistics and hypothesis testing were performed using IBM® SPSS® Statistics. A total of 43 CL and 7 ML cases were identified, with a predominance of autochthonous cases (86%). In CL, immunosuppressed individuals constituted a significant proportion of patients (48%), and in this group, disseminated CL (22%) and simultaneous VL (54%) were common. In autochthonous cases, lesions, mostly papules/nodules (62%), were frequently observed on the head (48%). The approach to treatment was very heterogeneous. ML cases were all autochthonous, were diagnosed primarily in older immunosuppressed individuals, and were generally treated with liposomal amphotericin B. The findings suggest a need for enhanced surveillance and reporting, clinical awareness, and diagnostic capacity of these forms of leishmaniasis to mitigate underdiagnosis and improve patient outcomes. A holistic One Health approach is advocated to address the multifaceted challenges posed by leishmaniases in Portugal and beyond.

Cecal Volvulus in an Elderly Woman: A Rare Cause of Bowel Obstruction.

Cecal volvulus is a rare, life-threatening form of bowel obstruction caused by the entanglement of the bowel around the mesenteric axis, compromising blood supply and leading to obstruction and ischemia. The diagnosis is challenging due to its highly variable clinical presentation and differential diagnoses, which may delay timely intervention. This is a case report of an 89-year-old woman who presented with a two-day history of lower right quadrant abdominal pain, nausea, and a temporary loss of consciousness. She also reported a history of chronic constipation. Clinical examination and imaging were suggestive of bowel obstruction, prompting further investigation. Plain radiography and abdominal CT confirmed bowel obstruction, with suspicion of volvulus. The diagnostic uncertainty between cecal and sigmoid volvulus prompted a colonoscopy, which excluded sigmoid volvulus. Emergency laparotomy revealed cecal volvulus and a distended cecum with ischemic changes but without necrosis. A right hemicolectomy was performed, and the patient recovered well postoperatively. This case report aims to expand the medical knowledge around the topic of cecal volvulus. It underscores the challenges in diagnosing and managing this condition and emphasizes the importance of prompt recognition and surgical intervention to improve patient outcomes.

Parental gonadossomatic mosaicism in HIVEP2-related intellectual disability and impact on genetic counseling-case report.

Intellectual development disorder, autosomal dominant 43 (MRD43) is an autosomal dominant disorder caused by heterozygous mutations in the HIVEP2 gene. In this report, we describe a case of a 4-year-old boy with global development delay, hypotonia, and dysmorphic features, in whom the finding of a heterozygous nonsense pathogenic variant in exon 5 of HIVEP2 [c.2827C>T p. (Arg943*)] through WES established a MRD43 diagnosis. Our patient's phenotype overlaps with other MRD43 descriptions in the literature. Unlike previously reported cases, where the condition was almost invariably de novo, the healthy mother in this case presented mosaicism for the pathogenic variant. Thus, the recurrence risk increased significantly from 1% to up to 50%. The description of a variant inherited for MDR43 is singular in the literature and this description highlights the importance of parental studies for accurate genetic counseling, particularly for family planning.

Brugada Phenocopy Caused by Intracranial Hemorrhage.

Brugada syndrome (BrS) is a congenital channelopathy associated with an increased risk of malignant ventricular arrhythmias and sudden cardiac death in individuals without any structural cardiopathy. Brugada phenocopies (BrPs) are clinical entities that present electrocardiographic patterns similar to those of BrS that are elicited only under transitory pathophysiological conditions, with normalization of the ECG pattern after the resolution of those conditions. We present a rare case of BrP due to intracranial hemorrhage. We also present and discuss the diagnostic criteria for BrPs and their application to this case.

Mice identify subgoal locations through an action-driven mapping process.

Mammals form mental maps of the environments by exploring their surroundings. Here, we investigate which elements of exploration are important for this process. We studied mouse escape behavior, in which mice are known to memorize subgoal locations-obstacle edges-to execute efficient escape routes to shelter. To test the role of exploratory actions, we developed closed-loop neural-stimulation protocols for interrupting various actions while mice explored. We found that blocking running movements directed at obstacle edges prevented subgoal learning; however, blocking several control movements had no effect. Reinforcement learning simulations and analysis of spatial data show that artificial agents can match these results if they have a region-level spatial representation and explore with object-directed movements. We conclude that mice employ an action-driven process for integrating subgoals into a hierarchical cognitive map. These findings broaden our understanding of the cognitive toolkit that mammals use to acquire spatial knowledge.

Gradenigo's Syndrome With Septic Lateral Sinus Thrombosis.

Gradenigo's syndrome (GS) is a rare but life-threatening complication of acute otitis media (AOM). It is classically defined as a clinical triad of acute otitis media, ipsilateral sixth (abducens) nerve palsy, and pain in the distribution of the first and second branches of the trigeminal nerve. Another rare but serious complication of AOM is venous sinus thrombosis, which is often associated with GS. The diagnosis of these conditions requires clinical suspicion, sound interpretation of signs and symptoms, and the use of the correct imaging techniques. Here, we present the case of an 81-year-old man with a previous history of recurrent otitis media, who presented with GS and septic lateral sinus thrombosis. The clinical presentation, physiopathology, and management of these conditions are discussed.

A cortico-collicular circuit for orienting to shelter during escape.

When faced with predatory threats, escape towards shelter is an adaptive action that offers long-term protection against the attacker. Animals rely on knowledge of safe locations in the environment to instinctively execute rapid shelter-directed escape actions1,2. Although previous work has identified neural mechanisms of escape initiation3,4, it is not known how the escape circuit incorporates spatial information to execute rapid flights along the most efficient route to shelter. Here we show that the mouse retrosplenial cortex (RSP) and superior colliculus (SC) form a circuit that encodes the shelter-direction vector and is specifically required for accurately orienting to shelter during escape. Shelter direction is encoded in RSP and SC neurons in egocentric coordinates and SC shelter-direction tuning depends on RSP activity. Inactivation of the RSP-SC pathway disrupts the orientation to shelter and causes escapes away from the optimal shelter-directed route, but does not lead to generic deficits in orientation or spatial navigation. We find that the RSP and SC are monosynaptically connected and form a feedforward lateral inhibition microcircuit that strongly drives the inhibitory collicular network because of higher RSP input convergence and synaptic integration efficiency in inhibitory SC neurons. This results in broad shelter-direction tuning in inhibitory SC neurons and sharply tuned excitatory SC neurons. These findings are recapitulated by a biologically constrained spiking network model in which RSP input to the local SC recurrent ring architecture generates a circular shelter-direction map. We propose that this RSP-SC circuit might be specialized for generating collicular representations of memorized spatial goals that are readily accessible to the motor system during escape, or more broadly, during navigation when the goal must be reached as fast as possible.

Refinements to rodent head fixation and fluid/food control for neuroscience.

The use of head fixation in mice is increasingly common in research, its use having initially been restricted to the field of sensory neuroscience. Head restraint has often been combined with fluid control, rather than food restriction, to motivate behaviour, but this too is now in use for both restrained and non-restrained animals. Despite this, there is little guidance on how best to employ these techniques to optimise both scientific outcomes and animal welfare. This article summarises current practices and provides recommendations to improve animal wellbeing and data quality, based on a survey of the community, literature reviews, and the expert opinion and practical experience of an international working group convened by the UK's National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs). Topics covered include head fixation surgery and post-operative care, habituation to restraint, and the use of fluid/food control to motivate performance. We also discuss some recent developments that may offer alternative ways to collect data from large numbers of behavioural trials without the need for restraint. The aim is to provide support for researchers at all levels, animal care staff, and ethics committees to refine procedures and practices in line with the refinement principle of the 3Rs.

Preparation of acute midbrain slices containing the superior colliculus and periaqueductal Gray for patch-clamp recordings.

This protocol is a practical guide for preparing acute coronal slices from the midbrain of young adult mice for electrophysiology experiments. It describes two different sets of solutions with their respective incubation strategies and two alternative procedures for brain extraction: decapitation under terminal isoflurane anaesthesia and intracardial perfusion with artificial cerebrospinal fluid under terminal isoflurane anaesthesia. Slices can be prepared from wild-type mice as well as from mice that have been genetically modified or transfected with viral constructs to label subsets of cells. The preparation can be used to investigate the electrophysiological properties of midbrain neurons in combination with pharmacology, opto- and chemogenetic manipulations, and calcium imaging; which can be followed by morphological reconstruction, immunohistochemistry, or single-cell transcriptomics. The protocol also provides a detailed list of materials and reagents including the design for a low-cost and easy to assemble 3D printed slice recovery chamber, general advice for troubleshooting common issues leading to suboptimal slice quality, and some suggestions to ensure good maintenance of a patch-clamp rig.

Differential Geometry Methods for Constructing Manifold-Targeted Recurrent Neural Networks.

Neural computations can be framed as dynamical processes, whereby the structure of the dynamics within a neural network is a direct reflection of the computations that the network performs. A key step in generating mechanistic interpretations within this computation through dynamics framework is to establish the link among network connectivity, dynamics, and computation. This link is only partly understood. Recent work has focused on producing algorithms for engineering artificial recurrent neural networks (RNN) with dynamics targeted to a specific goal manifold. Some of these algorithms require only a set of vectors tangent to the target manifold to be computed and thus provide a general method that can be applied to a diverse set of problems. Nevertheless, computing such vectors for an arbitrary manifold in a high-dimensional state space remains highly challenging, which in practice limits the applicability of this approach. Here we demonstrate how topology and differential geometry can be leveraged to simplify this task by first computing tangent vectors on a low-dimensional topological manifold and then embedding these in state space. The simplicity of this procedure greatly facilitates the creation of manifold-targeted RNNs, as well as the process of designing task-solving, on-manifold dynamics. This new method should enable the application of network engineering-based approaches to a wide set of problems in neuroscience and machine learning. Our description of how fundamental concepts from differential geometry can be mapped onto different aspects of neural dynamics is a further demonstration of how the language of differential geometry can enrich the conceptual framework for describing neural dynamics and computation.

Protocol to Study Spatial Subgoal Learning Using Escape Behavior in Mice.

Rodent spatial navigation is a key model system for studying mammalian cognition and its neural mechanisms. Of particular interest is how animals memorize the structure of their environments and compute multi-step routes to a goal. Previous work on multi-step spatial reasoning has generally involved placing rodents at the start of a maze until they learn to navigate to a reward without making wrong turns. It thus remains poorly understood how animals rapidly learn about the structure of naturalistic open environments with goals and obstacles. Here we present an assay in which mice spontaneously memorize two-step routes in an environment with a shelter and an obstacle. We allow the mice to explore this environment for 20 min, and then we remove the obstacle. We then present auditory threat stimuli, causing the mouse to escape to the shelter. Finally, we record each escape route and measure whether it targets the shelter directly (a 'homing-vector' escape) or instead targets the location where the obstacle edge was formerly located (an 'edge-vector' escape). Since the obstacle is no longer there, these obstacle-edge-directed escape routes provide evidence that the mouse has memorized a subgoal location, i.e., a waypoint targeted in order to efficiently get to the shelter in the presence of an obstacle. By taking advantage of instinctive escape responses, this assay probes a multi-step spatial memory that is learned in a single session without pretraining. The subgoal learning phenomenon it generates can be useful not only for researchers working on navigation and instinctive behavior, but also for neuroscientists studying the neural basis of multi-step spatial reasoning.

Threat history controls flexible escape behavior in mice.

In many instances, external sensory-evoked neuronal activity is used by the brain to select the most appropriate behavioral response. Predator-avoidance behaviors such as freezing and escape1,2 are of particular interest since these stimulus-evoked responses are behavioral manifestations of a decision-making process that is fundamental to survival.3,4 Over the lifespan of an individual, however, the threat value of agents in the environment is believed to undergo constant revision,5 and in some cases, repeated avoidance of certain stimuli may no longer be an optimal behavioral strategy.6 To begin to study this type of adaptive control of decision-making, we devised an experimental paradigm to probe the properties of threat escape in the laboratory mouse Mus musculus. First, we found that while robust escape to visual looming stimuli can be observed after 2 days of social isolation, mice can also rapidly learn that such stimuli are non-threatening. This learned suppression of escape (LSE) is extremely robust and can persist for weeks and is not a generalized adaptation, since flight responses to novel live prey and auditory threat stimuli in the same environmental context were maintained. We also show that LSE cannot be explained by trial number or a simple form of stimulus desensitization since it is dependent on threat-escape history. We propose that the action selection process mediating escape behavior is constantly updated by recent threat history and that LSE can be used as a robust model system to understand the neurophysiological mechanisms underlying experience-dependent decision-making.

Innate heuristics and fast learning support escape route selection in mice.

When faced with imminent danger, animals must rapidly take defensive actions to reach safety. Mice can react to threatening stimuli in ∼250 milliseconds1 and, in simple environments, use spatial memory to quickly escape to shelter.2,3 Natural habitats, however, often offer multiple routes to safety that animals must identify and choose from.4 This is challenging because although rodents can learn to navigate complex mazes,5,6 learning the value of different routes through trial and error during escape could be deadly. Here, we investigated how mice learn to choose between different escape routes. Using environments with paths to shelter of varying length and geometry, we find that mice prefer options that minimize path distance and angle relative to the shelter. This strategy is already present during the first threat encounter and after only ∼10 minutes of exploration in a novel environment, indicating that route selection does not require experience of escaping. Instead, an innate heuristic assigns survival value to each path after rapidly learning the spatial environment. This route selection process is flexible and allows quick adaptation to arenas with dynamic geometries. Computational modeling shows that model-based reinforcement learning agents replicate the observed behavior in environments where the shelter location is rewarding during exploration. These results show that mice combine fast spatial learning with innate heuristics to choose escape routes with the highest survival value. The results further suggest that integrating prior knowledge acquired through evolution with knowledge learned from experience supports adaptation to changing environments and minimizes the need for trial and error when the errors are costly.

Accurate determination of marker location within whole-brain microscopy images.

High-resolution whole-brain microscopy provides a means for post hoc determination of the location of implanted devices and labelled cell populations that are necessary to interpret in vivo experiments designed to understand brain function. Here we have developed two plugins (brainreg and brainreg-segment) for the Python-based image viewer napari, to accurately map any object in a common coordinate space. We analysed the position of dye-labelled electrode tracks and two-photon imaged cell populations expressing fluorescent proteins. The precise location of probes and cells were physiologically interrogated and revealed accurate segmentation with near-cellular resolution.

Multisensory coding of angular head velocity in the retrosplenial cortex.

To successfully navigate the environment, animals depend on their ability to continuously track their heading direction and speed. Neurons that encode angular head velocity (AHV) are fundamental to this process, yet the contribution of various motion signals to AHV coding in the cortex remains elusive. By performing chronic single-unit recordings in the retrosplenial cortex (RSP) of the mouse and tracking the activity of individual AHV cells between freely moving and head-restrained conditions, we find that vestibular inputs dominate AHV signaling. Moreover, the addition of visual inputs onto these neurons increases the gain and signal-to-noise ratio of their tuning during active exploration. Psychophysical experiments and neural decoding further reveal that vestibular-visual integration increases the perceptual accuracy of angular self-motion and the fidelity of its representation by RSP ensembles. We conclude that while cortical AHV coding requires vestibular input, where possible, it also uses vision to optimize heading estimation during navigation.

Loss of Seizure Control in a Patient With Vitamin D Deficiency and Phenytoin-Induced Hypocalcemia.

Phenytoin is a widely used antiseizure drug with well-documented side effects, including hypocalcemia, particularly in patients with concomitant vitamin D deficiency. Decreased serum calcium levels can induce seizures. In stabilized patients under long-term anticonvulsant treatment with phenytoin, loss of seizure control is rare but has been reported. This report illustrates a case of a 69-year-old woman under treatment with phenytoin for more than 10 years, who presented persistent hypocalcemia despite calcium correction, and seizures refractory to treatment with four combined antiepileptic drugs. She also presented with low vitamin D and elevated parathyroid hormone levels. Only when phenytoin administration was stopped it was possible to correct hypocalcemia and achieve seizure control. This case illustrates the need for regular monitoring and supplementation with calcium and vitamin D for patients under prolonged treatment with phenytoin. The proposed mechanism for phenytoin-induced hypocalcemia is reviewed. When installed, hypocalcemia can be resistant to supplementation until phenytoin is stopped, and in rare cases may lead to loss of seizure control.