High-throughput automated methods for classical and operant conditioning of Drosophila larvae.

Learning which stimuli (classical conditioning) or which actions (operant conditioning) predict rewards or punishments can improve chances of survival. However, the circuit mechanisms that underlie distinct types of associative learning are still not fully understood. Automated, high-throughput paradigms for studying different types of associative learning, combined with manipulation of specific neurons in freely behaving animals, can help advance this field. The Drosophila melanogaster larva is a tractable model system for studying the circuit basis of behaviour, but many forms of associative learning have not yet been demonstrated in this animal. Here, we developed a high-throughput (i.e. multi-larva) training system that combines real-time behaviour detection of freely moving larvae with targeted opto- and thermogenetic stimulation of tracked animals. Both stimuli are controlled in either open- or closed-loop, and delivered with high temporal and spatial precision. Using this tracker, we show for the first time that Drosophila larvae can perform classical conditioning with no overlap between sensory stimuli (i.e. trace conditioning). We also demonstrate that larvae are capable of operant conditioning by inducing a bend direction preference through optogenetic activation of reward-encoding serotonergic neurons. Our results extend the known associative learning capacities of Drosophila larvae. Our automated training rig will facilitate the study of many different forms of associative learning and the identification of the neural circuits that underpin them.

Pandemic lineage 2009 H1N1 influenza A virus infection in farmed mink in Utah.

Mink are susceptible to infection with influenza A virus (IAV) of swine and human origin. In 2019, a Utah mink farm had an outbreak of respiratory disease in kits caused by infection with the pandemic influenza A(H1N1)2009 virus [A(H1N1)pdm09]. In 3 wk, ~325, 1-2-wk-old kits died (10% mortality in kits). All deaths occurred in a single barn that housed 640 breeding females. No clinical signs or deaths occurred among adult mink. Five dead kits and 3 euthanized female mink were autopsied. All kits had moderate-to-severe neutrophilic and lymphohistiocytic interstitial pneumonia; adult mink had minimal-to-moderate lymphohistiocytic bronchointerstitial pneumonia. Immunohistochemistry and real-time PCR targeting the matrix gene detected IAV in lung of kits and adults. Virus isolation and genetic analysis identified the A(H1N1)pdm09 virus. The source of the virus was not determined but is thought to be the result of reverse zoonosis. Our case emphasizes the need for close monitoring on mink farms for interspecies transmission of IAV and for safe work practices on farms and in diagnostic laboratories. Additionally, a pandemic virus may continue to circulate at low levels long after the global event is declared over.

An outbreak of SARS-CoV-2 with high mortality in mink (Neovison vison) on multiple Utah farms.

The breadth of animal hosts that are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and may serve as reservoirs for continued viral transmission are not known entirely. In August 2020, an outbreak of SARS-CoV-2 occurred on five mink farms in Utah and was associated with high mink mortality (35-55% of adult mink) and rapid viral transmission between animals. The premise and clinical disease information, pathology, molecular characterization, and tissue distribution of virus within infected mink during the early phase of the outbreak are provided. Infection spread rapidly between independently housed animals and farms, and caused severe respiratory disease and death. Disease indicators were most notably sudden death, anorexia, and increased respiratory effort. Gross pathology examination revealed severe pulmonary congestion and edema. Microscopically there was pulmonary edema with moderate vasculitis, perivasculitis, and fibrinous interstitial pneumonia. Reverse transcriptase polymerase chain reaction (RT-PCR) of tissues collected at necropsy demonstrated the presence of SARS-CoV-2 viral RNA in multiple organs including nasal turbinates, lung, tracheobronchial lymph node, epithelial surfaces, and others. Localization of viral RNA by in situ hybridization revealed a more localized infection, particularly of the upper respiratory tract. Whole genome sequencing from multiple mink was consistent with published SARS-CoV-2 genomes with few polymorphisms. The Utah mink SARS-CoV-2 strains fell into Clade GH, which is unique among mink and other animal strains sequenced to date. While sharing the N501T mutation which is common in mink, the Utah strains did not share other spike RBD mutations Y453F and F486L found in nearly all mink from the United States. Mink in the outbreak reported herein had high levels of SARS-CoV-2 in the upper respiratory tract associated with symptomatic respiratory disease and death.

Making a Tiger's Day: Free-Operant Assessment and Environmental Enrichment to Improve the Daily Lives of Captive Bengal Tigers (Panthera tigris tigris).

There are more captive tigers in the United States than there are wild tigers in the entire world. Many animals under human care engage in problem behaviors such as excessive grooming and aggression, although the origin of these behaviors is typically unknown. Environmental enrichment may mitigate these issues in captive animals of all kinds. In order to individualize enrichment experiences, the current study used a free-operant assessment procedure to establish a menu of most preferred play items and scents among 7 Bengal tigers (Panthera tigris tigris) housed at a sanctuary in southwest Missouri. Each tiger was tested 3 times with scents (cinnamon and Calvin Klein Obsession perfume) and play items (boxes, balls, leaves, and pumpkins). The importance of rigorous assessment of presumed reinforcers among captive wild animals, as well as the difficulty of effectively assessing tigers while ensuring the safety of both the participants and researchers, is discussed.

Identifying Plant Poisoning in Livestock in North America.

Poisonous plant intoxication is one of the first considerations for various livestock diseases and unexplained animal deaths. Although toxic plants commonly poison livestock, obtaining a definitive diagnosis is difficult and challenging. This article provides a framework to help livestock producers, veterinarians, and diagnosticians reach the most accurate and definitive diagnosis. For this discussion poisoning caused by plants containing dehydropyrrolizidine alkaloids is used to provide examples and suggestions for investigating and sampling. It is also used to show how to recruit expert collaborators, diagnostic resources, and information sources to amass required expertise, information, and laboratory results to produce the best diagnosis.

Neurotoxic Plants that Poison Livestock.

In the western United States, poisonous plants most often affect grazing livestock, and the related livestock losses are estimated to cost the grazing livestock industry more than $200 million annually. Many of these toxic plants contain neurotoxins that damage or alter the function of neurologic cells in the central and peripheral nervous systems. The objectives of this article are to present common North American neurotoxic plants, including conditions of poisoning, clinical disease, pathologic changes, and available diagnostics, to identify poisoned animals and the potential prognosis for poisoned animals.

Plant-Induced Myotoxicity in Livestock.

Many toxic plants, ingested by livestock while grazing or eating contaminated processed feed, produce myoskeletal or myocardial lesions that sometimes have irreversible consequences. Some myotoxic plants are lethal after ingestion of very small amounts whereas others require consumption for many days to several weeks to produce disease. Incorporation of field studies, clinical signs, gross and microscopic pathology, and chemical identification of plants, toxins, and metabolites in animal samples is essential for an accurate diagnosis. This review introduces toxic plants that cause myotoxicity, reviews toxins and lesions, discusses analyses for making an accurate diagnosis, and summarizes treatments and recommendations to avoid future poisonings.

Plants Containing Urinary Tract, Gastrointestinal, or Miscellaneous Toxins that Affect Livestock.

Whether exposed by grazing toxic range or pasture plants or by eating contaminated feed, there are plant toxins that produce urinary tract disease, gastroenteritis, and other miscellaneous or multisystemic diseases. Diagnosis can be challenging and requires incorporation of field studies, clinical signs, gross and microscopic pathology, and chemical identification of plants, toxins, and metabolites in animal samples. The objectives of this review are to introduce poisonous plants that commonly poison livestock in North America; describe clinical and pathologic lesions they produce in livestock; and present current technology available to identify poisoning, treat affected animals, and minimize or avoid poisoning additional animals.

Hepatotoxic Plants that Poison Livestock.

The liver is one of the most commonly affected organs by ingested toxicants. This article familiarizes veterinarians with clinical signs, serum biochemistry changes, necropsy findings, and field information found in livestock poisonings with hepatotoxic plants. The focus is on the most common plant-derived hepatotoxins important to livestock in North America. Pyrrolizidine alkaloids are covered in greater detail than the other toxins, because they are likely the most important plant-derived toxins worldwide in livestock, wildlife, and even human exposure. Additionally, many of the principles discussed regarding clinical diagnosis of pyrrolizidine alkaloid intoxication can be applied to the other poisonous plants listed.

Plant-Induced Photosensitivity and Dermatitis in Livestock.

Whether poisoned by grazing certain toxic plants, by eating contaminated feed, or by topical contact with plant toxins, certain plants poison livestock causing photosensitivity and dermatitis. These dermal lesions are rarely fatal, and with appropriate therapy and protection from additional exposure most lesions heal with few permanent sequelae. However, these lesions often result in costly production losses and missed opportunities. The objectives of this review are to briefly introduce toxic plants that result in photosensitivity and dermatitis, review the toxins and pathogenesis of plant-induced skin disease, and summarize treatments and recommendations to avoid poisoning.

Plant-Induced Reproductive Disease, Abortion, and Teratology in Livestock.

Whether poisoned by grazing toxic plants or by eating feeds that are contaminated by toxic plants, affected livestock often have compromised reproductive function including infertility, abortion, and fetal deformities. Certainly all diagnostic tools-field studies, clinical signs, gross and microscopic pathology as well as chemical identification of plant and plant toxins in animal samples-are essential to make an accurate diagnosis, to develop intervening management strategies and to improve the reproductive performance. The objectives of this review are to briefly introduce toxic plants that are reproductive toxins, abortifacients, or teratogens.

Electrical stimulation of alpha oscillations stabilizes performance on visual attention tasks.

Neural oscillations in the alpha band (7-13 Hz) have long been associated with reductions in attention. However, recent studies have suggested a more nuanced perspective in which alpha oscillations also facilitate processes of cognitive control and perceptual stability. Transcranial alternating current stimulation (tACS) over occipitoparietal cortex at 10 Hz (alpha-tACS) can selectively enhance EEG alpha power. To assess the contribution of alpha oscillations to attention, we delivered alpha-tACS across 4 experiments while 178 participants performed sustained attention tasks. Poor performance on all visual tasks was previously associated with increased EEG alpha power. We therefore predicted initially that alpha-tACS would consistently impair visual task performance. However, alpha-tACS was instead found to prevent deteriorations in visual performance that otherwise occurred during sham- and 50 Hz-tACS. This finding was observed in 2 experiments, using different sustained attention tasks. In a separate experiment, we also found that alpha-tACS limited improvements on a visual task where learning was otherwise observed. Consequently, alpha-tACS appeared to exert a consistently stabilizing effect on visual attention. Such effects were not seen in an auditory control task, indicating specificity to the visual domain. We suggest that these results are most consistent with the view that alpha oscillations facilitate processes of top-down control and attentional stability. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Effects of 10 Hz Transcranial Alternating Current Stimulation on Audiovisual Task Switching.

Neural oscillations in the alpha band (7-13 Hz) are commonly associated with disengagement of visual attention. However, recent studies have also associated alpha with processes of attentional control and stability. We addressed this issue in previous experiments by delivering transcranial alternating current stimulation at 10 Hz over posterior cortex during visual tasks (alpha tACS). As this stimulation can induce reliable increases in EEG alpha power, and given that performance on each of our visual tasks was negatively associated with alpha power, we assumed that alpha tACS would reliably impair visual performance. However, alpha tACS was instead found to prevent both deteriorations and improvements in visual performance that otherwise occurred during sham & 50 Hz tACS. Alpha tACS therefore appeared to exert a stabilizing effect on visual attention. This hypothesis was tested in the current, pre-registered experiment by delivering alpha tACS during a task that required rapid switching of attention between motion, color, and auditory subtasks. We assumed that, if alpha tACS stabilizes visual attention, this stimulation should make it harder for people to switch between visual tasks, but should have little influence on transitions between auditory and visual subtasks. However, in contrast to this prediction, we observed no evidence of impairments in visuovisual vs. audiovisual switching during alpha vs. control tACS. Instead, we observed a trend-level reduction in visuoauditory switching accuracy during alpha tACS. Post-hoc analyses showed no effects of alpha tACS in response time variability, diffusion model parameters, or on performance of repeat trials. EEG analyses also showed no effects of alpha tACS on endogenous or stimulus-evoked alpha power. We discuss possible explanations for these results, as well as their broader implications for current efforts to study the roles of neural oscillations in cognition using tACS.

The many characters of visual alpha oscillations.

A central feature of human brain activity is the alpha rhythm: a 7-13 Hz oscillation observed most notably over occipitoparietal brain regions during periods of eyes-closed rest. Alpha oscillations covary with changes in visual processing and have been associated with a broad range of neurocognitive functions. In this article, we review these associations and suggest that alpha oscillations can be thought to exhibit at least five distinct 'characters': those of the inhibitor, perceiver, predictor, communicator and stabiliser. In short, while alpha oscillations are strongly associated with reductions in visual attention, they also appear to play important roles in regulating the timing and temporal resolution of perception. Furthermore, alpha oscillations are strongly associated with top-down control and may facilitate transmission of predictions to visual cortex. This is in addition to promoting communication between frontal and posterior brain regions more generally, as well as maintaining ongoing perceptual states. We discuss why alpha oscillations might associate with such a broad range of cognitive functions and suggest ways in which these diverse associations can be studied experimentally.

The roles of cortical oscillations in sustained attention.

We rely on sustained attention to protect task performance against fatigue and distraction. Time-related variations in attention correlate with amplitude changes of specific cortical oscillations. However, the ways in which these oscillations might support sustained attention, how these oscillations are controlled, and the extent to which they influence one another remain unclear. We address this issue by proposing an oscillatory model of sustained attention. Within this framework, sustained attention relies on frontomedial theta oscillations, inter-areal communication via low-frequency phase synchronisation, and selective excitation and inhibition of cognitive processing through gamma and alpha oscillations, respectively. Sustained attention also relies on interactions between these oscillations across attention-related brain networks.

Increasing seat belt use on a college campus: an evaluation of two prompting procedures.

Seat belt use is an important factor in the prevention of automobile accidents involving injuries and fatalities. The current study used a multielement design to compare the "Click It or Ticket" and "Please Buckle Up--I Care" procedures. Results indicate that the Click It or Ticket prompt resulted in a 20-percentage-point increase in seat belt use, and Please Buckle Up-I Care resulted in a 14-percentage-point increase.

Active prompting to decrease cell phone use and increase seat belt use while driving.

Automobile crashes are the leading cause of death for those aged 3 to 33, with 43,005 (118 per day) Americans killed in 2002 alone. Seat belt use reduces the risk of serious injury in an accident, and refraining from using a cell phone while driving reduces the risk of an accident. Cell phone use while driving increases accident rates, and leads to 2,600 U.S. fatalities each year. An active prompting procedure was employed to increase seat belt use and decrease cell phone use among drivers exiting a university parking lot. A multiple baseline with reversal design was used to evaluate the presentation of two signs: "Please Hang Up, I Care" and "Please Buckle Up, I Care." The proportion of drivers who complied with the seat belt prompt was high and in line with previous research. The proportion of drivers who hung up their cell phones in response to the prompt was about equal to that of the seat belt prompt. A procedure that reduces cell phone use among automobile drivers is a significant contribution to the behavioral safety literature.