Cholinergic Interneurons Control Local Circuit Activity and Cocaine Conditioning

Cholinergic neurons are widespread, and pharmacological modulation of acetylcholine receptors affects numerous brain processes, but such modulation entails side effects due to limitations in specificity for receptor type and target cell. As a result, causal roles of cholinergic neurons in circuits have been unclear. We integrated optogenetics, freely moving mammalian behavior, in vivo electrophysiology, and slice physiology to probe the cholinergic interneurons of the nucleus accumbens by direct excitation or inhibition. Despite representing less than 1% of local neurons, these cholinergic cells have dominant control roles, exerting powerful modulation of circuit activity. Furthermore, these neurons could be activated by cocaine, and silencing this drug-induced activity during cocaine exposure (despite the fact that the manipulation of the cholinergic interneurons was not aversive by itself) blocked cocaine conditioning in freely moving mammals

Optogenetic Brain Interfaces

The brain is a large network of interconnected neurons where each cell functions as a nonlinear processing element. Unraveling the mysteries of information processing in the complex networks of the brain requires versatile neurostimulation and imaging techniques. Optogenetics is a new stimulation method which allows the activity of neurons to be modulated by light. For this purpose, the cell-types of interest are genetically targeted to produce light-sensitive proteins. Once these proteins are expressed, neural activity can be controlled by exposing the cells to light of appropriate wavelengths. Optogenetics provides a unique combination of features, including multimodal control over neural function and genetic targeting of specific cell-types. Together, these versatile features combine to a powerful experimental approach, suitable for the study of the circuitry of psychiatric and neurological disorders. The advent of optogenetics was followed by extensive research aimed to produce new lines of light-sensitive proteins and to develop new technologies: for example, to control the distribution of light inside the brain tissue or to combine optogenetics with other modalities including electrophysiology, electrocorticography, nonlinear microscopy, and functional magnetic resonance imaging. In this paper, the authors review some of the recent advances in the field of optogenetics and related technologies and provide their vision for the future of the field.United States. Defense Advanced Research Projects Agency (Space and Naval Warfare Systems Center, Pacific Grant/Contract No. N66001-12-C-4025)University of Wisconsin--Madison (Research growth initiative; grant 101X254)University of Wisconsin--Madison (Research growth initiative; grant 101X172)University of Wisconsin--Madison (Research growth initiative; grant 101X213)National Science Foundation (U.S.) (MRSEC DMR-0819762)National Science Foundation (U.S.) (NSF CAREER CBET-1253890)National Institutes of Health (U.S.) (NIH/NIBIB R00 Award (4R00EB008738)National Institutes of Health (U.S.) (NIH Director’s New Innovator award (1-DP2-OD002989))Okawa Foundation (Research Grant Award)National Institutes of Health (U.S.) (NIH Director’s New Innovator Award (1DP2OD007265))National Science Foundation (U.S.) (NSF CAREER Award (1056008)Alfred P. Sloan Foundation (Fellowship)Human Frontier Science Program (Strasbourg, France) (Grant No. 1351/12)Israeli Centers of Research Excellence (I-CORE grant, program 51/11)MINERVA Foundation (Germany

Estimating motion, size and material properties of moving non-line-of-sight objects in cluttered environments

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 111-117).The thesis presents a framework for Non-Line-of-Sight Computer Vision techniques using wave fronts. Using short-pulse illumination and a high speed time-of-flight camera, we propose algorithms that use multi path light transport analysis to explore the environments beyond line of sight. What is moving around the corner interests everyone including a driver taking a turn, a surgeon performing laparoscopy and a soldier entering enemy base. State of the art techniques that do range imaging are limited by (i) inability to handle multiple diffused bounces [LIDAR] (ii) Wavelength dependent resolution limits [RADAR] and (iii) inability to map real life objects [Diffused Optical Tomography]. This work presents a framework for (a) Imaging the changing Space-time-impulse-responses of moving objects to pulsed illumination (b) Tracking motion along with absolute positions of these hidden objects and (c) recognizing their default properties like material and size and reflectance. We capture gated space-time impulse responses of the scene and their time differentials allow us to gauge absolute positions of moving objects with knowledge of only relative times of arrival (as absolute times are hard to synchronize at femto second intervals). Since we record responses at very short time intervals we collect multiple readings from different points of illumination and thus capturing multi-perspective responses allowing us to estimate reflectance properties. Using this, we categorize and give parametric models of the materials around corner. We hope this work inspires further exploration of NLOS computer vision techniques.by Rohit Pandharkar.S.M

Agriculture, nutrition and gender in India

The South Asian region has one of the highest rates of child and maternal undernutrition in the world. Undernutrition is widespread and persistent even in India despite its relatively strong economic performance and is particularly high in rural areas and among those in agriculture based livelihoods. Though agriculture has the enormous potential to contribute to improvements in undernutrition, the evidence so far in the Indian context demonstrates weak linkages between agriculture and nutrition . This research brief summarises the key findings from the different studies focusing on women’s agency and nutrition undertaken by LANSA in India.Department for International Development (DFID)UKAI

Agriculture-nutrition linkages and child undernutrition in India

The South Asian region and in particular India, has one of the highest rates of child undernutrition in the world, and is home to around 40 per cent of the global total of children who are stunted. Child stunting has been shown to have severe lifelong economic, health, and cognitive disadvantages and costs. Despite improvements in some states in recent years, the levels continue to be high. Understanding the reasons for the high prevalence of child undernutrition in India in the face of the relatively strong economic performance has emerged as an important research topic and is an area of focus of LANSA’s research in the region. Under the research theme, ‘How enabling is the wider context in linking agriculture and food systems to other determinants of nutritional status?’, LANSA research in India focuses on understanding the barriers and facilitators to nutrition-sensitive agricultural development in the country. The analyses and empirical work on the available large secondary datasets from India are expected to elaborate on the pathways that connect agriculture and nutrition and the type and degree of interaction with other non-food drivers. This research brief summarises the key findings from some of the studies undertaken by LANSA partners, on agriculture-nutrition linkages and child undernutrition in India.Department for International Development (DFID)UKAI

Knowledge, attitude and practice of preventing spread of COVID-19 amongst orthopaedic surgeons and residents in a tertiary care hospital in Navi-Mumbai

Background: With on-going coronavirus pandemic, there is high incidence of COVID-19 occupational risk exposure among health care professionals. The aim of this study was to assess the knowledge, attitude and practice (KAP) amongst orthopaedic surgeons and residents regarding prevention of spread of COVID-19 at a tertiary care hospital.Methods: A cross-sectional, observational, web-based questionnaire study was conducted at orthopaedic department of a tertiary care hospital in Navi Mumbai. The study included orthopaedic surgeons and residents of either sex. A predesigned KAP questionnaire was used to assess the knowledge, attitude and practice regarding prevention of spread of COVID-19. The web-based questionnaire was circulated to eligible participants and the responses obtained were analysed.Results: Overall, the knowledge regarding hand hygiene, mask etiquette and COVID-19 diagnoses was high. Majority participants knew the proper technique of personal protective equipment (PPE), but few 25% and 35% lacked correct technique for donning and doffing of PPE respectively. Majority participants knew the indications and pre/post-operative protocols for orthopaedic surgeries in COVID-19. Around 40% only knew the type of pressure system used in the COVID-19 operation theatre (OT). Majority felt that mask, hand hygiene and PPE were essential kit for prevention. In practice, majority participants were taking drug prophylaxis and were adequately practicing mask/hand hygiene.Conclusions: Overall, KAP regarding prevention of spread of COVID-19 among orthopaedicians were adequate. Further formal preventive education on COVID-19 and structured hands-on experience workshops are necessary to advance the proper techniques of PPE handling

Hierarchical inverse reinforcement learning from motion capture data

A human motion generally consists of multiple low-level tasks which are performed in a defined order or in parallel to achieve a high level task. For example, making pizza dough consists of several low-level tasks such as measuring water, adding yeast, measuring flour, etc. And these activities must be performed in a definite order to make the dough. For a system to imitate these sequence of activities of a long horizon task with one global reward function is a lot of work. This process can be made easier if there is hierarchical state representation of the task and learning of local rewards for the hierarchies. In this thesis, we have learned to imitate a general day to day human activity of ’setting table for one person’. This work adopts a framework called Hierarchical Inverse Reinforcement Learning (HIRL), which is a model to learn sub-task structure from demonstrations. With this framework, the activity is decomposed into multiple lower level tasks which are performed in a sequence using learned policies. In this work, Maximum Entropy Inverse Reinforcement Learning (MaxEnt-IRL) is used to learn local rewards for the sub-tasks. Together with hierarchical state space representation and local reward functions, the model encodes the high level task objective based on human demonstrations of full body motion performing the high level task. The model achieves a success rate of 84% on average for middle levels and 83% for the top level in the cross validation tests. For visualization, the model is simulated in a 2D representation that takes current environment state as input and runs till the completion of the task

Principles for applying optogenetic tools derived from direct comparative analysis of microbial opsins

Diverse optogenetic tools have allowed versatile control over neural activity. Many depolarizing and hyperpolarizing tools have now been developed in multiple laboratories and tested across different preparations, presenting opportunities but also making it difficult to draw direct comparisons. This challenge has been compounded by the dependence of performance on parameters such as vector, promoter, expression time, illumination, cell type and many other variables. As a result, it has become increasingly complicated for end users to select the optimal reagents for their experimental needs. For a rapidly growing field, critical figures of merit should be formalized both to establish a framework for further development and so that end users can readily understand how these standardized parameters translate into performance. Here we systematically compared microbial opsins under matched experimental conditions to extract essential principles and identify key parameters for the conduct, design and interpretation of experiments involving optogenetic techniques

Fair and Efficient Completion of Indivisible Goods

We formulate the problem of fair and efficient completion of indivisible goods, defined as follows: Given a partial allocation of indivisible goods among agents, does there exist an allocation of the remaining goods (i.e., a completion) that satisfies fairness and economic efficiency guarantees of interest? We study the computational complexity of the completion problem for prominent fairness and efficiency notions such as envy-freeness up one good (EF1), proportionality up to one good (Prop1), maximin share (MMS), and Pareto optimality (PO), and focus on the class of additive valuations as well as its subclasses such as binary additive and lexicographic valuations. We find that while the completion problem is significantly harder than the standard fair division problem (wherein the initial partial allocation is empty), the consideration of restricted preferences facilitates positive algorithmic results for threshold-based fairness notions (Prop1 and MMS). On the other hand, the completion problem remains computationally intractable for envy-based notions such as EF1 and EF1+PO even under restricted preferences