The dorsal visual stream, the cortical circuit that in the primate brain is mainly dedicated to the visual control of actions, is split into two routes, a lateral and a medial one, both involved in ...coding different aspects of sensorimotor control of actions. The lateral route, named “lateral grasping network”, is mainly involved in the control of the distal part of prehension, namely grasping and manipulation. The medial route, named “reach-to-grasp network”, is involved in the control of the full deployment of prehension act, from the direction of arm movement to the shaping of the hand according to the object to be grasped. In macaque monkeys, the reach-to-grasp network (the target of this review) includes areas of the superior parietal lobule (SPL) that hosts visual and somatosensory neurons well suited to control goal-directed limb movements toward stationary as well as moving objects. After a brief summary of the neuronal functional properties of these areas, we will analyze their cortical and thalamic inputs thanks to retrograde neuronal tracers separately injected into the SPL areas V6, V6A, PEc, and PE. These areas receive visual and somatosensory information distributed in a caudorostral, visuosomatic trend, and some of them are directly connected with the dorsal premotor cortex. This review is particularly focused on the origin and type of visual information reaching the SPL, and on the functional role this information can play in guiding limb interaction with objects in structured and dynamic environments.
COVID-19 causes acute respiratory distress syndrome (ARDS) and depletes the lungs of surfactant, leading to prolonged mechanical ventilation and death. The feasibility and safety of surfactant ...delivery in COVID-19 ARDS patients have not been established.
We performed retrospective analyses of data from patients receiving off-label use of exogenous natural surfactant during the COVID-19 pandemic. Seven COVID-19 PCR positive ARDS patients received liquid Curosurf (720 mg) in 150 ml normal saline, divided into five 30 ml aliquots) and delivered via a bronchoscope into second-generation bronchi. Patients were matched with 14 comparable subjects receiving supportive care for ARDS during the same time period. Feasibility and safety were examined as well as the duration of mechanical ventilation and mortality.
Patients showed no evidence of acute decompensation following surfactant installation into minor bronchi. Cox regression showed a reduction of 28-days mortality within the surfactant group, though not significant. The surfactant did not increase the duration of ventilation, and health care providers did not convert to COVID-19 positive.
Surfactant delivery through bronchoscopy at a dose of 720 mg in 150 ml normal saline is feasible and safe for COVID-19 ARDS patients and health care providers during the pandemic. Surfactant administration did not cause acute decompensation, may reduce mortality and mechanical ventilation duration in COVID-19 ARDS patients. This study supports the future performance of randomized clinical trials evaluating the efficacy of meticulous sub-bronchial lavage with surfactant as treatment for patients with COVID-19 ARDS.
The posterior parietal cortex is well known to mediate sensorimotor transformations during the generation of movement plans, but its ability to control prosthetic limbs in 3D environments has not yet ...been fully demonstrated. With this aim, we trained monkeys to perform reaches to targets located at various depths and directions and tested whether the reach goal position can be extracted from parietal signals. The reach goal location was reliably decoded with accuracy close to optimal (>90%), and this occurred also well before movement onset. These results, together with recent work showing a reliable decoding of hand grip in the same area, suggest that this is a suitable site to decode the entire prehension action, to be considered in the development of brain-computer interfaces.
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•Depths and directions of reaching actions are reliably decoded by the parietal cortex•Goal locations are discriminated well before movement onset•The entire prehension action could be decoded from a single cortical site•Neuroprosthetics from the medial parietal cortex can restore lost reach/grasp functions
Filippini et al. show that it is possible to use parietal cortex activity to predict in which direction the arm will move and how far it will reach. This opens up the possibility of neural prostheses that can accurately guide reach and grasp using signals from this part of the brain.
Perception and action are fundamental processes that characterize our life and our possibility to modify the world around us. Several pieces of evidence have shown an intimate and reciprocal ...interaction between perception and action, leading us to believe that these processes rely on a common set of representations. The present review focuses on one particular aspect of this interaction: the influence of action on perception from a motor effector perspective during two phases, action planning and the phase following execution of the action. The movements performed by eyes, hands, and legs have a different impact on object and space perception; studies that use different approaches and paradigms have formed an interesting general picture that demonstrates the existence of an action effect on perception, before as well as after its execution. Although the mechanisms of this effect are still being debated, different studies have demonstrated that most of the time this effect pragmatically shapes and primes perception of relevant features of the object or environment which calls for action; at other times it improves our perception through motor experience and learning. Finally, a future perspective is provided, in which we suggest that these mechanisms can be exploited to increase trust in artificial intelligence systems that are able to interact with humans.
The posterior parietal cortex (PPC) serves as a crucial hub for the integration of sensory with motor cues related to voluntary actions. Visual input is used in different ways along the dorsomedial ...and the dorsolateral visual pathways. Here we focus on the dorsomedial pathway and recognize a visual representation at the service of action control. Employing different experimental paradigms applied to behaving monkeys while single neural activity is recorded from the medial PPC (area V6A), we show how plastic visual representation can be, matching the different contexts in which the same object is proposed. We also present data on the exchange between vision and arm actions and highlight how this rich interplay can be used to weight different sensory inputs in order to monitor and correct arm actions online. Indeed, neural activity during reaching or reach-to-grasp actions can be excited or inhibited by visual information, suggesting that the visual perception of action, rather than object recognition, is the most effective factor for area V6A. Also, three-dimensional object shape is encoded dynamically by the neural population, according to the behavioral context of the monkey. Along this line, mirror neuron discharges in V6A indicate the plasticity of visual representation of the graspable objects, that changes according to the context and peaks when the object is the target of one’s own action. In other words, object encoding in V6A is a visual encoding for action.
In the past, neuroscience was focused on individual neurons seen as the functional units of the nervous system, but this approach fell short over time to account for new experimental evidence, ...especially for what concerns associative and motor cortices. For this reason and thanks to great technological advances, a part of modern research has shifted the focus from the responses of single neurons to the activity of neural ensembles, now considered the real functional units of the system. However, on a microscale, individual neurons remain the computational components of these networks, thus the study of population dynamics cannot prescind from studying also individual neurons which represent their natural substrate. In this new framework, ideas such as the capability of single cells to encode a specific stimulus (neural selectivity) may become obsolete and need to be profoundly revised. One step in this direction was made by introducing the concept of “mixed selectivity,” the capacity of single cells to integrate multiple variables in a flexible way, allowing individual neurons to participate in different networks. In this review, we outline the most important features of mixed selectivity and we also present recent works demonstrating its presence in the associative areas of the posterior parietal cortex. Finally, in discussing these findings, we present some open questions that could be addressed by future studies.
The current organizational structure of the Italian healthcare system does not include the institutionalization of clinical ethics services. To describe the need for structured clinical ethics ...consultation services for ICU staff members in the intensive care unit (ICU), a monocentric observational survey study was performed utilizing a paper-based questionnaire.
A total of 73 healthcare professionals (HCPs) responded out of a team of 84 people (87%). The results showed that the need for ethics consultation in the ICU is urgent, the institutionalization of the clinical ethics service is perceived as useful and should be a priority, and the issues on which the HCPs would like ethics consultation to focus are various and belong to "end of life" topics.
HCPs believe that the clinical ethicist should become an integral part of ICU healthcare teams, offering consultations similar to the other specialistic consultations carried out in hospitals.
The activity of neurons of the medial posterior parietal area V6A in macaque monkeys is modulated by many aspects of reach task. In the past, research was mostly focused on modulating the effect of ...single parameters upon the activity of V6A cells. Here, we used Generalized Linear Models (GLMs) to simultaneously test the contribution of several factors upon V6A cells during a fix-to-reach task. This approach resulted in the definition of a representative “functional fingerprint” for each neuron. We first studied how the features are distributed in the population. Our analysis highlighted the virtual absence of units strictly selective for only one factor and revealed that most cells are characterized by “mixed selectivity.” Then, exploiting our GLM framework, we investigated the dynamics of spatial parameters encoded within V6A. We found that the tuning is not static, but changed along the trial, indicating the sequential occurrence of visuospatial transformations helpful to guide arm movement.
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•The parietal cortex integrates a variety of sensorimotor inputs to guide reaching•GLM disentangled the effect of various reaching parameters upon cell activity•V6A neurons were not functionally clustered, but characterized by mixed selectivity•Spatial selectivity was dynamic and reached its peak during the movement phase
Neuroscience; Behavioral Neuroscience; Biocomputational Method
The protocol provides an extensive guide to apply the generalized linear model framework to neurophysiological recordings. This flexible technique can be adapted to test and quantify the ...contributions of many different parameters (e.g., kinematics, target position, choice, reward) on neural activity. To weight the influence of each parameter, we developed an intuitive metric (“w-value”) that can be used to build a “functional fingerprint” characteristic for each neuron. We also provide suggestions to extract complementary useful information from the method.
For complete details on the use and execution of this protocol, please refer to Diomedi et al. (2020).
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•GLM applied to neuronal discharges reveals parameters that modulate their activity•Applying regularizers helps to discard minority parameters and reduces noise•Each neuron can be characterized by the weight assigned to each parameter tested•Results are well suited for population analyses (i.e., clustering, correlation, etc)
The protocol provides an extensive guide to apply the generalized linear model framework to neurophysiological recordings. This flexible technique can be adapted to test and quantify the contributions of many different parameters (e.g., kinematics, target position, choice, reward) on neural activity. To weight the influence of each parameter, we developed an intuitive metric (“w-value”) that can be used to build a “functional fingerprint” characteristic for each neuron. We also provide suggestions to extract complementary useful information from the method.
To study disease activity during pregnancy and obstetric outcomes in patients with juvenile idiopathic arthritis (JIA) upon different subsets and with focus on medication use. Retrospective ...observational study of 22 pregnancies in 16 JIA patients (95.5% Caucasian) who were followed between 2010 and 2018. Disease activity, flares and medications were recorded before conception, during each trimester and postpartum period. Pregnancies occurred in 10 (45.5%) oligoarticular extended (OLA-E), 6 (27.3%) in polyarticular (PLA), 4 in (18.2%) systemic (SYS), 1 (4.5%) in oligoarticular persistent (OLA-P) and 1 (4.5%) in enthesitis-related arthritis (ERA) JIA patients. The median age at disease diagnosis and at conception was 5.5 and 28 years (respectively). The median disease duration was 20 years. Nineteen (95%) pregnancies started in a period of stable disease remission. Among the 22 pregnancies, 20 ended with a live birth (90.9%). No spontaneous miscarriages occurred; two voluntary interruption of pregnancy were performed. There were 7 flares in 6/20 pregnancies (35%) and 8 flares (8/22, 36.4%) occurred in postpartum period, all of them in OLA-E and PLA patients. Seven patients (35%) were taking biological disease-modifying anti-rheumatic drugs (bDMARDs) at conception, and 6 of them stopped this treatment at positive pregnancy test. Five patients resumed bDMARDs either during pregnancy (3 exposed during the third trimester) or puerperium due to a flare. Four preterm deliveries (20%) were recorded, all in patients who had a flare during pregnancy. The preconception counselling should include the evaluation of disease subset, as OLA-E and PLA may flare more than other subsets, especially if bDMARDs are discontinued at positive pregnancy test. Continuation of bDMARDs during pregnancy should be considered to minimize the risk of adverse pregnancy outcomes, particularly preterm delivery.
Key Points
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In our cohort, all the flares during pregnancy and 75% of postpartum flares were observed in patients who withdrew bDMARDs and cDMARDs at the beginning of pregnancy.
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Flares were observed only in PLA and OLA-E patients.
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Preterm delivery occurred in 20% of the pregnancies; all of these patients had a disease flare during pregnancy.
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