Single-Molecule Spectral Fluctuation Originates from the Variation in Dipole Orientation Connected to Accessible Vibrational Modes.

Fluctuation in fluorescence emission of an immobilized single molecule is typically ascribed to the chromophore's intrinsic structural conformations and the influence of local environmental factors. Despite extensive research since its initial observation, a direct connection between these spectral fluctuations and the rearrangement of emission dipole orientations has remained elusive. Here, we elucidate this fundamental molecular behavior and its underlying mechanisms by employing unique single-molecule multidimensional tracking to simultaneously monitor both the emission spectrum and the three-dimensional dipole orientation of individual fluorophores.

Expression perceptive fields explain individual differences in the recognition of facial emotions.

Humans can use the facial expressions of another to infer their emotional state, although it remains unknown how this process occurs. Here we suppose the presence of perceptive fields within expression space, analogous to feature-tuned receptive-fields of early visual cortex. We developed genetic algorithms to explore a multidimensional space of possible expressions and identify those that individuals associated with different emotions.

Simulation training in mammography with AI-generated images: a multireader study.

Objectives: The interpretation of mammograms requires many years of training and experience. Currently, training in mammography, like the rest of diagnostic radiology, is through institutional libraries, books, and experience accumulated over time. We explore whether artificial Intelligence (AI)-generated images can help in simulation education and result in measurable improvement in performance of residents in training.

Mesostriatal dopamine is sensitive to changes in specific cue-reward contingencies.

Learning causal relationships relies on understanding how often one event precedes another. To investigate how dopamine neuron activity and neurotransmitter release change when a retrospective relationship is degraded for a specific pair of events, we used outcome-selective Pavlovian contingency degradation in rats. Conditioned responding was attenuated for the cue-reward contingency that was degraded, as was dopamine neuron activity in the midbrain and dopamine release in the ventral striatum in response to the cue and subsequent reward.

Mesolimbic dopamine ramps reflect environmental timescales.

Mesolimbic dopamine activity occasionally exhibits ramping dynamics, reigniting debate on theories of dopamine signaling. This debate is ongoing partly because the experimental conditions under which dopamine ramps emerge remain poorly understood. Here, we show that during Pavlovian and instrumental conditioning, mesolimbic dopamine ramps are only observed when the inter-trial interval is short relative to the trial period.

Sensory cortical ensembles exhibit differential coupling to ripples in distinct hippocampal subregions.

Cortical neurons activated during recent experiences often reactivate with dorsal hippocampal CA1 ripples during subsequent rest. Less is known about cortical interactions with intermediate hippocampal CA1, whose connectivity, functions, and ripple events differ from dorsal CA1. We identified three clusters of putative excitatory neurons in mouse visual cortex that are preferentially excited together with either dorsal or intermediate CA1 ripples or suppressed before both ripples.

Measuring Economic Benefits of Built Environment Accessibility Technologies for People with Disabilities.

Given the challenges of wayfinding in large indoor built environments, especially for persons with disabilities (PWDs), a new class of accessible technologies called built environment accessible technologies (BEAT) are being developed. Such technologies are envisioned to help achieve product and opportunity parity for PWDs. The impact and adoption of these BEATs depends largely on clear and quantifiable (tangible and intangible) economic benefits accrued to the end-users and stakeholders.

Genetic algorithms reveal identity independent representation of emotional expressions.

People readily and automatically process facial emotion and identity, and it has been reported that these cues are processed both dependently and independently. However, this question of identity independent encoding of emotions has only been examined using posed, often exaggerated expressions of emotion, that do not account for the substantial individual differences in emotion recognition. In this study, we ask whether people's unique beliefs of how emotions should be reflected in facial expressions depend on the identity of the face.

An open-source behavior controller for associative learning and memory (B-CALM).

Associative learning and memory, i.e., learning and remembering the associations between environmental stimuli, self-generated actions, and outcomes such as rewards or punishments, are critical for the well-being of animals.

Single-Molecule Orientation Imaging Reveals Two Distinct Binding Configurations on Amyloid Fibrils.

Fluorescence readouts for an amyloid fibril sensor critically depend on its molecular interaction and local environment offered by the available structural motifs. Here we employ polarized points accumulation for imaging in nanoscale topography with intramolecular charge transfer probes transiently bound to amyloid fibrils to investigate the organization of fibril nanostructures and probe binding configurations. Besides the in-plane (θ ≈ 90°) mode for binding on the fibril surface parallel to the long fibril axis, we also observed a sizable population of over 60% out-of-plane (θ < 60°) dipoles for rotor probes experiencing a varying degree of orientational mobility.

Sensory cortical ensembles exhibit differential coupling to ripples in distinct hippocampal subregions.

Cortical neurons activated during recent experiences often reactivate with dorsal hippocampal CA1 sharp-wave ripples (SWRs) during subsequent rest. Less is known about cortical interactions with intermediate hippocampal CA1, whose connectivity, functions, and SWRs differ from those of dorsal CA1. We identified three clusters of visual cortical excitatory neurons that are excited together with either dorsal or intermediate CA1 SWRs, or suppressed before both SWRs.

Post-traumatic stress and depression following a landslide linked to the 2018 floods in Kerala, India: Relevance of screening.

There is scant information on early manifestation of trauma due to catastrophic natural events and its relation with stress-related disorders. The specific objective of this study was to estimate and compare the prevalence of post-traumatic stress and depression on day 3 (D3) and week 6 (W6) following the 2018 flood in Kerala, India. In a cross-sectional study, symptoms of post-traumatic stress and depression were studied at D3 using primary care Post-Traumatic Stress Disorder screen for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) (PC-PTSD-5), and then at W6 using PC-PTSD-5, Screening Questionnaire for Disaster Mental Health, PTSD Checklist for DSM-5 (PCL-5), and Becks Depression Inventory.

Mesolimbic dopamine release conveys causal associations.

Learning to predict rewards based on environmental cues is essential for survival. It is believed that animals learn to predict rewards by updating predictions whenever the outcome deviates from expectations, and that such reward prediction errors (RPEs) are signaled by the mesolimbic dopamine system-a key controller of learning. However, instead of learning prospective predictions from RPEs, animals can infer predictions by learning the retrospective cause of rewards.

Rectification-Based Knowledge Retention for Task Incremental Learning.

In the task incremental learning problem, deep learning models suffer from catastrophic forgetting of previously seen classes/tasks as they are trained on new classes/tasks. This problem becomes even harder when some of the test classes do not belong to the training class set, i.e.

Ethanol dehydration performance of three types of commercial-grade zeolite permselective membranes.

Background: Many organic solvents form difficult-to-separate mixtures with water and have an affinity for water, making drying a potential reuse prerequisite. Pervaporation (PV) and vapor permeation (VP) membrane technologies hold promise for energy-efficient solvent drying. Several water-selective membrane materials are commercially available, but performance data is limited, particularly for two recently commercialized membrane materials: chabazite (CHA) and T-type zeolites.

How do real animals account for the passage of time during associative learning?

Animals routinely learn to associate environmental stimuli and self-generated actions with their outcomes such as rewards. One of the most popular theoretical models of such learning is the reinforcement learning (RL) framework. The simplest form of RL, model-free RL, is widely applied to explain animal behavior in numerous neuroscientific studies.

Picosecond to Second Fluorescence Correlation Spectroscopy for Studying Solute Exchange and Quenching Dynamics in Micellar Media.

Numerous studies have been devoted to understand the reaction kinetics in micelles, where the accessible kinetic time window is often limited by the dynamic range of the employed spectroscopic technique. This is usually accompanied by a selection of probes that comfortably explore time scales where slow solute exchange kinetics is negligible, as compared to the fast excited state reactions. This has led to an undervaluation of the role played by dynamic partitioning of hydrophilic solutes in microheterogeneous media.

Artificial Intelligence-assisted chest X-ray assessment scheme for COVID-19.

Objectives: To study whether a trained convolutional neural network (CNN) can be of assistance to radiologists in differentiating Coronavirus disease (COVID)-positive from COVID-negative patients using chest X-ray (CXR) through an ambispective clinical study. To identify subgroups of patients where artificial intelligence (AI) can be of particular value and analyse what imaging features may have contributed to the performance of AI by means of visualisation techniques.

Methods: CXR of 487 patients were classified into [4] categories-normal, classical COVID, indeterminate, and non-COVID by consensus opinion of 2 radiologists.

Uncertainty Class Activation Map (U-CAM) Using Gradient Certainty Method.

Understanding and explaining deep learning models is an imperative task. Towards this, we propose a method that obtains gradient-based certainty estimates that also provide visual attention maps. Particularly, we solve for visual question answering task.

Prepronociceptin-Expressing Neurons in the Extended Amygdala Encode and Promote Rapid Arousal Responses to Motivationally Salient Stimuli.

Motivational states consist of cognitive, emotional, and physiological components controlled by multiple brain regions. An integral component of this neural circuitry is the bed nucleus of the stria terminalis (BNST). Here, we identify that neurons within BNST that express the gene prepronociceptin (Pnoc) modulate rapid changes in physiological arousal that occur upon exposure to motivationally salient stimuli.

Heterogeneous Habenular Neuronal Ensembles during Selection of Defensive Behaviors.

Optimal selection of threat-driven defensive behaviors is paramount to an animal's survival. The lateral habenula (LHb) is a key neuronal hub coordinating behavioral responses to aversive stimuli. Yet, how individual LHb neurons represent defensive behaviors in response to threats remains unknown.

Developments from Bulk Optogenetics to Single-Cell Strategies to Dissect the Neural Circuits that Underlie Aberrant Motivational States.

Motivational states are regulated by complex networks across brain regions that are composed of genetically and functionally distinct neuronal populations. Disruption within these neural circuits leads to aberrant motivational states and are thought to be the root cause of psychiatric disorders related to reward processing and addiction. Critical technological advances in the field have revolutionized the study of neural systems by allowing the use of optical strategies to precisely control and visualize neural activity within genetically identified neural populations in the brain.

Interoceptive Inception in Insula.

The neural mechanisms underlying interoception-the sensation of internal physiological states-remain largely unresolved. In this issue of Neuron, Livneh et al. (2020) demonstrate that the insula bridges different timescales of interoception by tracking and predicting thirst and hunger states.

Social Stimuli Induce Activation of Oxytocin Neurons Within the Paraventricular Nucleus of the Hypothalamus to Promote Social Behavior in Male Mice.

Oxytocin (OT) is critical for the expression of social behavior across a wide array of species; however, the role of this system in the encoding of socially relevant information is not well understood. In the present study, we show that chemogenetic activation of OT neurons within the paraventricular nucleus of the hypothalamus (PVH) of male mice (OT-Ires-Cre) enhanced social investigation during a social choice test, while chemogenetic inhibition of these neurons abolished typical social preferences. These data suggest that activation of the OT system is necessary to direct behavior preferentially toward social stimuli.