Circling Behavior Research Articles

Ketamine modulates the exploratory dynamics and homebase-related behaviors of adult zebrafish

Anxiety is a protective behavior when animals face aversive conditions, but commonly associated with various neuropsychiatric disorders when exacerbated. Drug repurposing has emerged as a valuable strategy to use existing pharmaceuticals for new therapeutic purposes. Ketamine, traditionally used as an anesthetic, acts as a non-competitive antagonist of the N-methyl-d-aspartate (NMDA) receptor, and evidence has shown potential anxiolytic and antidepressant effects at subanesthetic doses. However, the influence of ketamine on multiple behavioral domains in vertebrates is not completely understood. Here, we evaluated the potential modulatory effect of ketamine on the spatio-temporal exploratory dynamics and homebase-related behaviors in adult zebrafish using the open field test (OFT). Animals were exposed to subanesthetic concentrations of ketamine (0, 2, 20, and 40 mg/L) for 20 min and locomotion- exploration- and homebase-related behaviors were assessed in a single 30-min trial. Our data revealed that ketamine (20 and 40 mg/L) induced hyperlocomotion, as verified by the increased total distance traveled. All concentrations tested elicited circling behavior, a stereotyped-like response which gradually reduced across the periods of test. We also observed modulatory effects of ketamine on the spatio-temporal exploratory pattern, in which the reduced thigmotaxis and homebase activity, associated with the increased average length of trips were suggestive of anxiolytic-like effects. Collectively, our novel findings support the modulatory effects of ketamine on the spatio-temporal exploratory activity, as well as the utility of homebase-related measurements to evaluate the behavioral dynamics of zebrafish.

An open-source tool for automated human-level circling behavior detection

Quantitatively relating behavior to underlying biology is crucial in life science. Although progress in keypoint tracking tools has reduced barriers to recording postural data, identifying specific behaviors from this data remains challenging. Manual behavior coding is labor-intensive and inconsistent, while automatic methods struggle to explicitly define complex behaviors, even when they seem obvious to the human eye. Here, we demonstrate an effective technique for detecting circling in mice, a form of locomotion characterized by stereotyped spinning. Despite circling's extensive history as a behavioral marker, there currently exists no standard automated detection method. We developed a circling detection technique using simple postprocessing of keypoint data obtained from videos of freely-exploring (Cib2−/−;Cib3−/−) mutant mice, a strain previously found to exhibit circling behavior. Our technique achieves statistical parity with independent human observers in matching occurrence times based on human consensus, and it accurately distinguishes between videos of wild type mice and mutants. Our pipeline provides a convenient, noninvasive, quantitative tool for analyzing circling mouse models without the need for software engineering experience. Additionally, as the concepts underlying our approach are agnostic to the behavior being analyzed, and indeed to the modality of the recorded data, our results support the feasibility of algorithmically detecting specific research-relevant behaviors using readily-interpretable parameters tuned on the basis of human consensus.

How Japanese eels escape from the stomach of a predatory fish

Predation shapes diversity in the defensive tactics of prey. One specialized defensive tactic is to escape the digestive system of the predator after capture1,2,3,4,5,6,7,8. While most of these defensive tactics involve passive ejection alive from predators' mouths and vents1,2,3,4,5, active escape from the digestive tracts of predators has recently been observed in certain invertebrate species6,7 and fish8. However, no study has yet uncovered the behavioral patterns and escape routes of the prey within a predator's digestive tract. Here, we report the sequential escape processes of the Japanese eel Anguilla japonica from capture to escape via the gills of predatory fish Odontobutis obscura using an X-ray video system. All captured eels had at least one portion of their bodies swallowed into the stomach of the predator. Surprisingly, after being swallowed, most individuals attempted to escape by going back up the digestive tract towards the esophagus and gill, and some of them succeeded in escaping via the predator's gill. Some eels, whose entire bodies were completely inside the stomach, exhibited circling behavior along the stomach, seemingly searching for possible escape routes. An electro-anesthetization experiment revealed that eels utilize various escape routes through gill clefts, rather than just one.

Clinical and magnetic resonance imaging features of unilateral thalamic porencephaly in a dog

AbstractA 1‐year‐3‐month‐old, female, neutered labrador retriever was presented with a history of circling behaviour since 2 months of age and a recently detected blindness affecting its right eye. Neurological examination revealed a left‐sided head tilt, compulsive tight circling towards the left, postural reaction deficits in the right thoracic and pelvic limbs, absent menace response in the right eye and ventral positional strabismus of the left eye. The neurological examination findings were localised to the left thalamus. Magnetic resonance imaging of the head revealed porencephaly involving the left dorsal aspect of the thalamus. Furthermore, reduced volume of the left rostral colliculus, crus cerebri and optic chiasm, alongside marked thinning of the left cerebral hemispheric white matter tracts with associated left lateral ventriculomegaly, were present. Based on magnetic resonance imaging features and clinical history, a congenital or perinatal encephaloclastic porencephaly with secondary hypoplasia or atrophy of the associated thalamic projection pathways was prioritised.

A novel copy number variant in the murine Cdh23 gene gives rise to profound deafness and vestibular dysfunction.

Hearing loss is the most common congenital sensory deficit worldwide and exhibits high genetic heterogeneity, making molecular diagnoses elusive for most individuals. Detecting novel mutations that contribute to hearing loss is crucial to providing accurate personalized diagnoses, tailored interventions, and improving prognosis. Copy number variants (CNVs) are structural mutations that are understudied, potential contributors to hearing loss. Here, we present the Abnormal Wobbly Gait (AWG) mouse, the first documented mutant exhibiting waltzer-like locomotor dysfunction, hyperactivity, circling behaviour, and profound deafness caused by a spontaneous CNV deletion in cadherin 23 (Cdh23). We were unable to identify the causative mutation through a conventional whole-genome sequencing (WGS) and variant detection pipeline, but instead found a linked variant in hexokinase 1 (Hk1) that was insufficient to recapitulate the AWG phenotype when introduced into C57BL/6J mice using CRISPR-Cas9. Investigating nearby deafness-associated genes revealed a pronounced downregulation of Cdh23 mRNA and a complete absence of full-length CDH23 protein, which is critical for the development and maintenance of inner ear hair cells, in whole head extracts from AWG neonates. Manual inspection of WGS read depth plots of the Cdh23 locus revealed a putative 10.4kb genomic deletion of exons 11 and 12 that was validated by PCR and Sanger sequencing. This study underscores the imperative to refine variant detection strategies to permit identification of pathogenic CNVs easily missed by conventional variant calling to enhance diagnostic precision and ultimately improve clinical outcomes for individuals with genetically heterogenous disorders such as hearing loss.

Optogenetic fMRI reveals therapeutic circuits of subthalamic nucleus deep brain stimulation

While deep brain stimulation (DBS) is widely employed for managing motor symptoms in Parkinson's disease (PD), its exact circuit mechanisms remain controversial. To identify the neural targets affected by therapeutic DBS in PD, we analyzed DBS-evoked whole brain activity in female hemi-parkinsonian rats using functional magnetic resonance imaging (fMRI). We delivered subthalamic nucleus (STN) DBS at various stimulation pulse repetition rates using optogenetics, allowing unbiased examination of cell-type specific STN feedforward neural activity. Unilateral optogenetic STN DBS elicited pulse repetition rate-dependent alterations of blood-oxygenation-level-dependent (BOLD) signals in SNr (substantia nigra pars reticulata), GP (globus pallidus), and CPu (caudate putamen). Notably, this modulation effectively ameliorated pathological circling behavior in animals expressing the kinetically faster Chronos opsin, but not in animals expressing ChR2. Furthermore, mediation analysis revealed that the pulse repetition rate-dependent behavioral rescue was significantly mediated by optogenetic DBS induced activity changes in GP and CPu, but not in SNr. This suggests that the activation of GP and CPu are critically involved in the therapeutic mechanisms of STN DBS.

Artificial structure selection by economically important reef fishes at North Carolina artificial reefs

Artificial reefs can play an important role in marine fisheries management by supplementing or enhancing natural habitats. Despite their increased use in recent years, the choice of structures used at artificial reefs remains largely haphazard due to the lack of information on reef structure performance. Few studies have examined the use of different artificial reef structures by individual fish. From 2021-2022, we acoustically tagged 72 black sea bass (Centropristis striata), 34 gag (Mycteroperca mircrolepis), 27 greater amberjack (Seriola dumerili), nine almaco jack (S. rivoliana), and eight red snapper (Lutjanus campechanus) on four artificial reef complexes near Cape Lookout, North Carolina, U.S. Available artificial reef structures consisted of materials of various sizes and heights made of concrete and metal. We tracked tagged fish using a fine-scale positioning system for ~100 days. Black sea bass exhibited high site fidelity to the artificial structure where we caught them, rarely moving away from that structure. The limited movement resulted in low transition probabilities; we conclude that black sea bass do not select for particular artificial structures. Gag and red snapper moved greater distances away from artificial structures and routinely moved between them. Greater amberjack and almaco jack moved the most within the complexes displaying circling behavior around individual structures and were the only species that regularly moved off the artificial reef complexes. Greater amberjack movements away from artificial sites were most commonly directed to surrounding shipwrecks. Whereas gag, red snapper, almaco jack, and greater amberjack used all available structures, they consistently selected for high relief structures, such as vessels, more than other structures. These results will be useful to managers charged with decisions on what types of structures to place at artificial reef complexes to supplement or enhance habitat for economically important fishes.

Phenotypical, genotypical and pathological characterization of the moonwalker mouse, a model of ataxia

We performed a comprehensive study of the morphological, functional, and genetic features of moonwalker (MWK) mice, a mouse model of spinocerebellar ataxia caused by a gain of function of the TRPC3 channel. These mice show numerous behavioral symptoms including tremor, altered gait, circling behavior, impaired motor coordination, impaired motor learning and decreased limb strength. Cerebellar pathology is characterized by early and almost complete loss of unipolar brush cells as well as slowly progressive, moderate loss of Purkinje cell (PCs). Structural damage also includes loss of synaptic contacts from parallel fibers, swollen ER structures, and degenerating axons. Interestingly, no obvious correlation was observed between PC loss and severity of the symptoms, as the phenotype stabilizes around 2 months of age, while the cerebellar pathology is progressive. This is probably due to the fact that PC function is severely impaired much earlier than the appearance of PC loss. Indeed, PC firing is already impaired in 3 weeks old mice. An interesting feature of the MWK pathology that still remains to be explained consists in a strong lobule selectivity of the PC loss, which is puzzling considering that TRPC is expressed in every PC. Intriguingly, genetic analysis of MWK cerebella shows, among other alterations, changes in the expression of both apoptosis inducing and resistance factors possibly suggesting that damaged PCs initiate specific cellular pathways that protect them from overt cell loss.

Formation of intraneuronal iron deposits following local release from nanostructured silica injected into rat brain parenchyma

Nanostructured materials with controllable properties have been used to cage and release various types of compounds. In the present study, iron-loaded nanostructured sol-gel SiO2–Fe materials were prepared and injected into the rat brain to develop a method for gradual iron delivery into the neurons with the aims to avoid acute iron toxicity and develop an animal model of gradual, metal-induced neurodegeneration. Nanoparticles were prepared by the traditional method of hydrolysis and condensation reactions of tetraethyl orthosilicate at room temperature and subsequent heat treatment at 200 °C. FeSO4 was added in situ during the silica preparation. The resulting materials were characterized by UV-VIS and infrared spectroscopies, X-ray diffraction, and N2 adsorption-desorption. An in vitro ferrous sulfate release test was carried out in artificial cerebrospinal fluid as the release medium showing successful ferrous sulfate loading on nanostructured silica and sustained iron release during the test time of 10 h. Male Wistar rats administered with SiO2–Fe nanoparticles in the substantia nigra pars compacta (SNpc) showed significant intraneuronal increase of iron, in contrast to the animals administered with FeSO4 that showed severe neuronal loss, 72 h post-treatment. Both treatments induced lipid fluorescent product formation in the ventral midbrain, in contrast to iron-free SiO2 and PBS-only injection controls. Circling behavior was evaluated six days after the intranigral microinjection, considered as a behavioral end-point of brain damage. The apomorphine-induced ipsilateral turns in the treated animals presented significant differences in relation to the control groups, with FeSO4 administration leading to a dramatic phenotype, compared to a milder impact in SiO2–Fe administrated animals. Thus, the use of SiO2–Fe nanoparticles represents a slow iron release system useful to model the gradual iron-accumulation process observed in the SNpc of patients with idiopathic Parkinson's disease.

The effects of social environment on AD-related pathology in hAPP-J20 mice and tau-P301L mice

In humans, social factors (e.g., loneliness) have been linked to the risk of developing Alzheimer's Disease (AD). To date, AD pathology is primarily characterized by amyloid-β plaques and tau tangles. We aimed to assess the effect of single- and group-housing on AD-related pathology in a mouse model for amyloid pathology (J20, and WT controls) and a mouse model for tau pathology (P301L) with and without seeding of synthetic human tau fragments (K18).Female mice were either single housed (SH) or group housed (GH) from the age of 6–7 weeks onwards. In 12-week-old P301L mice, tau pathology was induced through seeding by injecting K18 into the dorsal hippocampus (P301LK18), while control mice received a PBS injection (P301LPBS). P301L mice were sacrificed at 4 months of age and J20 mice at 10 months of age. In all mice brain pathology was histologically assessed by examining microglia, the CA1 pyramidal cell layer and specific AD pathology: analysis of plaques in J20 mice and tau hyperphosphorylation in P301L mice.Contrary to our expectation, SH-J20 mice interestingly displayed fewer plaques in the hippocampus compared to GH-J20 mice. However, housing did not affect tau hyperphosphorylation at Ser202/Thr205 of P301L mice, nor neuronal cell death in the CA1 region in any of the mice. The number of microglia was increased by the J20 genotype, and their activation (based on cell body to cell size ratio) in the CA1 was affected by genotype and housing condition (interaction effect). Single housing of P301L mice was linked to the development of stereotypic behavior (i.e. somersaulting and circling behavior). In P301LK18 mice, an increased number of microglia were observed, among which were rod microglia.Taken together, our findings point to a significant effect of social housing conditions on amyloid plaques and microglia in J20 mice and on the development of stereotypic behavior in P301L mice, indicating that the social environment can modulate AD-related pathology.

Dual-AAV vector-mediated expression of MYO7A improves vestibular function in a mouse model of Usher syndrome 1B

Usher syndrome is the most common cause of deafness-blindness in the world. Usher syndrome type 1B (USH1B) is associated with mutations in MYO7A. Patients with USH1B experience deafness, blindness, and vestibular dysfunction. In this study, we applied adeno-associated virus (AAV)-mediated gene therapy to the shaker-1 (Myo7a4626SB/4626SB) mouse, a model of USH1B. The shaker-1 mouse has a nonsense mutation in Myo7a, is profoundly deaf throughout life, and has significant vestibular dysfunction. Because of the ∼6.7-kb size of the MYO7A cDNA, a dual-AAV approach was used for gene delivery,which involves splitting human MYO7A cDNA into 5' and 3' halves and cloning them into two separate AAV8(Y733F) vectors. When MYO7A cDNA was delivered to shaker-1 inner ears using the dual-AAV approach, cochlear hair cell survival was improved. However, stereocilium organization and auditory function were not improved. In contrast, in the vestibular system, dual-AAV-mediated MYO7A delivery significantly rescued hair cell stereocilium morphology and improved vestibular function, as reflected in a reduction of circling behavior and improved vestibular sensory-evoked potential (VsEP) thresholds. Our data indicate that dual-AAV-mediated MYO7A expression improves vestibular function in shaker-1 mice and supports further development of this approach for the treatment of disabling dizziness from vestibular dysfunction in USH1B patients.

Repurposing Simvastatin in Parkinson’s Disease Model: Protection Is throughout Modulation of the Neuro-Inflammatory Response in the Substantia nigra

Parkinson’s disease is a neurodegenerative disorder characterized by oxidative stress and immune activation in the nigro-striatal pathway. Simvastatin regulates cholesterol metabolism and protects from atherosclerosis disease. Simvastatin-tween 80 was administered 7 days before sterotaxic intrastriatal administration of MPP+ (1-methyl-4-phenylpyridine) in rats. Fluorescent lipidic product formation, dopamine levels, and circling behavior were considered damage markers. Twenty-four hours and six days after, the animal group lesioned with MPP+ showed significant damage in relation to the control group. Animals pretreated with simvastatin significantly reduced the MPP+-induced damage compared to the MPP+ treated group. As apoptosis promotes neuroinflammation and neuronal degeneration in Parkinson’s disease, and since there is not currently a proteomic map of the nigro-striatum of rats and assuming a high homology among the identified proteins in other rat tissues, we based the search for rat protein homologs related to the establishment of inflammation response. We demonstrate that most proteins related to inflammation decreased in the simvastatin-treated rats. Furthermore, differential expression of antioxidant enzymes in striated tissue of rat brains was found in response to simvastatin. These results suggest that simvastatin could prevent striatal MPP+-induced damage and, for the first time, suggest that the molecular mechanisms involved in this have a protective effect.

Quantitative analysis and correlative evaluation of video-oculography, micro-computed tomography, and histopathology in Pendrin-null mice

Patients with SLC26A4 mutations exhibit highly variable hearing loss and vestibular dysfunction. Although Slc26a4 mutant mice similarly exhibit vestibular deficits, including circling behavior, head tilting, and torticollis, the underlying pathogenesis of the vestibular symptoms remains unclear, hindering its effective management for patients with SLC26A4 mutations. In this study, we evaluated the equilibrium function using the inspection equipment, which can record eye movements against rotational, gravitational, and thermal stimulations. Moreover, we correlated the degree of functional impairment with the morphological alterations observed in Slc26a4Δ/Δ mice. The rotational stimulus and ice water caloric tests revealed considerable impairment of the semicircular canal, while the tilted gravitational stimulus test showed a severe functional decline of the otolithic system in Slc26a4Δ/Δ mice. Generally, the degree of impairment was more severe in circling Slc26a4Δ/Δ mice than in non-circling Slc26a4Δ/Δ mice. In non-circling Slc26a4Δ/Δ mice, the semicircular canal function was normal. Micro-computed tomography results showed enlargement of the vestibular aqueduct and bony semicircular canals but no correlative relationship between the severity of the caloric response and the size of bony labyrinths. Giant otoconia and a significant decrease in total otolith volume in the saccule and utricle were observed in Slc26a4Δ/Δ mice. However, the giant otoconia were not overly dislocated in the bony otolithic system and ectopic otoconia were absent in the semicircular canal. The number and morphology of the utricular hair cells in Slc26a4Δ/Δ mice were not significantly reduced compared to those in Slc26a4Δ/+ mice. Collectively, we can conclude that vestibular impairments are mainly associated with otoconia formation and morphology rather than hair cell degeneration. In addition, severe disturbances of semicircular canals cause circling behavior in Slc26a4Δ/Δ mice. Our comprehensive morphological and functional assessments apply to mouse models of other genetic diseases with vestibular impairment.

Acetic acid-induced pain elicits stress-, and camouflage-related responses in zebrafish: Modulatory effects of opioidergic drugs on neurobehavioral phenotypes

While pain results from the activation of nociceptors following noxious stimuli, mounting evidence links pain- and stress-related responses in mammals. In zebrafish, the activation of hypothalamic-pituitary-interrenal (HPI) axis may also regulate body pigmentation (the camouflage response). Here, we aimed to investigate a putative relationship between pain-, stress-, and camouflage-related parameters in adult zebrafish. To answer this question, we assessed whether intraperitoneal acetic acid injection can activate the HPI axis, measuring whole-body cortisol and the camouflage response as physiological endpoints in the presence or absence of morphine or naloxone, an opioid antagonist. Acetic acid induced a stereotypic circling behavior in the top of the tank, accompanied by abdominal writhing-like response, a specific phenotype that reflects local nociceptive effect. Both whole-body cortisol levels and camouflage response increased in the acetic acid group, while morphine prevented these responses, and naloxone antagonized morphine-induced effects. Moreover, we observed positive correlations between representative behavioral, physiological and skin coloration endpoints, and a “pain index” was proposed to summarize phenotypic profile of zebrafish under different pharmacological manipulations. Collectively, these findings suggest a coordinated activation of pain, camouflage- and stress-related pathways following acetic acid injection in zebrafish. Our data also support that camouflage response represents a novel and relevant biomarker for future probing pain and stress neurobiology, with a robust sensitivity to opioidergic drugs.

Developmental cadmium exposure disrupts zebrafish vestibular calcium channels interfering with otolith formation and inner ear function

Dizziness or balance problems are estimated to affect approximately 3.3 million children aged three to 17 years. These disorders develop from a breakdown in the balance control system and can be caused by anything that affects the inner ear or the brain, including exposure to environmental toxicants. One potential environmental toxicant linked to balance disorders is cadmium, an extremely toxic metal that occurs naturally in the earth’s crust and is released as a byproduct of industrial processes. Cadmium is associated with balance and vestibular dysfunction in adults exposed occupationally, but little is known about the developmental effects of low-concentration cadmium exposure. Our findings indicate that zebrafish exposed to 10–60 parts per billion (ppb) cadmium from four hours post-fertilization (hpf) to seven days post-fertilization (dpf) exhibit abnormal behaviors, including pronounced increases in auditory sensitivity and circling behavior, both of which are linked to reductions in otolith growth and are rescued by the addition of calcium to the media. Pharmacological intervention shows that agonist-induced activation of the P2X calcium ion channel in the presence of cadmium restores otolith size. In conclusion, cadmium-induced ototoxicity is linked to vestibular-based behavioral abnormalities and auditory sensitivity following developmental exposure, and calcium ion channel function is associated with these defects.

The suitability of zebrafish (danio rerio) as an optimal organism to further investigate the associated schizophrenia-like phenotype

IntroductionZebrafish (Danio rerio) has evolved over the years as a preferred organism due to its vast repertoire in research fields that mimic a targeted phenotype, particularly behavioral typologies and specific attributes comparable to murine models and relatively high homology with humans. Considering this consideration, different pharmacological treatments have been tested and proven that under different concentrations may trigger schizophrenia (SCZ)-like symptoms.ObjectivesStarting from the actual stage of knowledge according to which agents used as N-methyl-D-aspartate (NMDA) inhibitors (MK-801, ketamine, and phencyclidine) alongside psychedelic (mescaline, lysergic acid diethylamide), psychoactive substances (amphetamine), and non- and essential amino acids (proline and methionine), we aimed to reunite and review all existing evidence. This approach may offer an updated and critical overview regarding the possible future directions surrounding these compounds regarding the pharmaco-dynamics/kinetics.MethodsTo ensure the coverage of all relevant literature, we performed searches in four databases (PubMed/Medline, ISI Web of Knowledge, Scopus, and ScienceDirect) per combinations of keywords: “schizophrenia” with “MK-801”, “ketamine”, “phencyclidine”, “mescaline”, “lysergic acid diethylamide”, “amphetamine”, “proline”, “methionine”, and “zebrafish”. Eligible studies had to be “research article(s)” written in English.ResultsA total of n = 246 studies were returned during the established interval (2010 – 2022). Precisely, n = 16 were identified in PubMed/Medline, n = 16 in ISI Web of Knowledge, n = 17 in Scopus, and n = 197 in ScienceDirect per database. If taken per year, n = 13 were published in 2010, n = 12 in 2011, n = 15 in 2012, n = 24 in 2013, n = 21 in 2014, n = 21 in 2015, n = 32 in 2016, n = 8 in 2017, n = 12 in 2018, n = 9 in 2019, n = 17 in 2020, n = 34 in 2021, and n = 28 in 2022. Depending on the combination of keywords, we had the following situation: n = 65 for “schizophrenia+MK-801+zebrafish”, n = 42 for “schizophrenia+ketamine+zebrafish”, n = 21 for “schizophrenia+phencyclidine+zebrafish”, n = 4 for “schizophrenia+mescaline+zebrafish”, n = 5 for “schizophrenia+lysergic acid diethylamide+zebrafish”, n = 36 for “schizophrenia+amphetamine+zebrafish”, n = 37 for “schizophrenia+proline+zebrafish”, n = 36 for “schizophrenia+ methionine+zebrafish”.ConclusionsThere can be seen an uprising trend in the current literature of studies focused on the administration of MK-801, ketamine, amphetamine, proline, methionine, and phencyclidine aiming to trigger SCZ-like symptoms as opposed to mescaline and lysergic acid diethylamide. Most of the data is contradicting, with either a decrease/increase in behavior (locomotion, aggression, sociability, circling behavior, and memory deficits), which is why additional studies are mandatory.Disclosure of InterestNone Declared

Behavior-Based Herding Algorithm for Social Force Model Based Sheep Herd

Inspired by real-world sheepdog herding behavior, in this paper, four behavior-based herding algorithms have been proposed for the social force model-based sheep herd. First, a basic behavior-based herding algorithm is designed where four types of critical sheep are rigorously defined. The decision of the sheepdog is made by constantly checking the positions of these four critical sheep. Then, on top of this basic herding algorithm, two extra mechanisms are considered to improve the performance of the basic herding algorithm, namely the dynamic far-end mechanism and the pausing mechanism, thus, forming the other three herding algorithms. The dynamic far-end mechanism helps to avoid the undesired circling behavior of the sheepdog around the destination area, while the pausing mechanism can greatly reduce the control cost of the sheepdog. To validate the effectiveness of the proposed herding algorithms, comprehensive tests have been conducted. The performance of the four algorithms is evaluated and compared from three aspects, namely, success rate, completion step, and control cost. Moreover, parameter analysis is provided to examine how different design parameters will affect the performance of the proposed algorithm. Finally, it is shown that when the size of the sheep herd increases, as expected, it takes more time and control effort to complete herding.

Whole-body analysis of TRPML3 (MCOLN3) expression using a GFP-reporter mouse model reveals widespread expression in secretory cells and endocrine glands.

TRPML3 (mucolipin 3, MCOLN3) is an endolysosomal cation channel belonging to the TRPML subfamily of transient receptor potential channels. Gain-of-function mutations in the Trpml3 gene cause deafness, circling behavior and coat color dilution in mice due to cell death of TRPML3-expressing hair cells of the inner ear or skin melanocytes, respectively. Furthermore, TRPML3 was found to play a role in the long term survival of cochlear hair cells (its absence contributing to presbycusis), in specialized giant lysosomes that neonatal (birth to weaning) enterocytes used for the uptake and digestion of maternal milk nutrients, and in the expulsion of exosome-encased bacteria such as uropathogenic E. coli, infecting bladder epithelial cells. Recently, TRPML3 was found to be expressed at high levels in alveolar macrophages and loss of TRPML3 results in a lung emphysema phenotype, confirmed in two independently engineered Trpml3 knockout lines. TRPML3 is not ubiquitously expressed like its relative TRPML1 and thus cellular expression of TRPML3 on a whole-tissue level remains, with the exceptions mentioned above, largely elusive. To overcome this problem, we generated a τGFP reporter mouse model for TRPML3 and compared expression data obtained from this model by immunofluorescence on tissue sections with immunohistochemistry using TRPML3 antibodies and in situ hybridization. We thus uncovered expression in several organs and distinct cell types. We confirmed TRPML3 expression in both neonatal and adult alveolar macrophages, in melanocytes of hair follicles and glabrous skin, in principle cells of the collecting duct of the neonatal and adult kidney, and in olfactory sensory neurons of the olfactory epithelium, including its fibres protruding to the glomeruli of the olfactory bulb. Additionally, we localized TRPML3 in several glands including parathyroid, thyroid, salivary, adrenal, and pituitary gland, testes and ovaries, suggestive of potential roles for the channel in secretion or uptake of different hormones.

Circles in the sea: annual courtship "torus" behaviour of basking sharks Cetorhinus maximus identified in the eastern North Atlantic Ocean.

Groups of basking sharks engaged in circling behaviour are rarely observed, and their function remains enigmatic in the absence of detailed observations. Here, underwater and aerial video recordings of multiple circling groups of basking sharks during late summer (August and September 2016-2021) in the eastern North Atlantic Ocean showed groups numbering between 6 and 23 non-feeding individuals of both sexes. Sharks swam slowly in a rotating "torus" (diameter range: 17-39 m), with individuals layered vertically from the surface to a maximum depth of 16 m. Within a torus, sharks engaged in close-following, echelon, close-flank approach or parallel-swimming behaviours. Measured shark total body lengths were 5.4-9.5m (mean LT : 7.3m ± 0.9s.d.; median: 7.2m, n= 27), overlapping known lengths of sexually mature males and females. Males possessed large claspers with abrasions that were also observed on female pectoral fins. Female body colouration was paler than that of males, similar to colour changes observed during courtship and mating in other shark species. Individuals associated with most other members rapidly (within minutes), indicating toroidal behaviours facilitate multiple interactions. Sharks interacted through fin-fin and fin-body contacts, rolling to expose the ventral surfaces to following sharks, and breaching behaviour. Toruses formed in late summer when feeding aggregations in zooplankton-rich thermal fronts switched to non-feeding following and circling behaviours. Collectively, the observations explain a courtship function for toruses. This study highlights northeast Atlantic coastal waters as a critical habitat supporting courtship reproductive behaviour of endangered basking sharks, the first such habitat identified for this species globally.

Quinolinic Acid Induces Alterations in Neuronal Subcellular Compartments, Blocks Autophagy Flux and Activates Necroptosis and Apoptosis in Rat Striatum.

Quinolinic acid (QUIN) is an agonist of N-methyl-D-aspartate receptor (NMDAr) used to study the underlying mechanism of excitotoxicity in animal models. There is evidence indicating that impairment in autophagy at early times contributes to cellular damage in excitotoxicity; however, the status of autophagy in QUIN model on day 7 remains unexplored. In this study, the ultrastructural analysis of subcellular compartments and the status of autophagy, necroptosis, and apoptosis in the striatum of rats administered with QUIN (120nmol and 240nmol) was performed on day 7. QUIN induced circling behavior, neurodegeneration, and cellular damage; also, it promoted swollen mitochondrial crests, spherical-like morphology, and mitochondrial fragmentation; decreased ribosomal density in the rough endoplasmic reticulum; and altered the continuity of myelin sheaths in axons with separation of the compact lamellae. Furthermore, QUIN induced an increase and a decrease in ULK1 and p-70-S6K phosphorylation, respectively, suggesting autophagy activation; however, the increased microtubule-associated protein 1A/1B-light chain 3-II (LC3-II) and sequestosome-1/p62 (SQSTM1/p62), the coexistence of p62 and LC3 in the same structures, and the decrease in Beclin 1 and mature cathepsin D also indicates a blockage in autophagy flux. Additionally, QUIN administration increased tumor necrosis factor alpha (TNFα) and receptor-interacting protein kinase 3 (RIPK3) levels and its phosphorylation (p-RIPK3), as well as decreased B-cell lymphoma 2 (Bcl-2) and increased Bcl-2-associated X protein (Bax) levels and c-Jun N-terminal kinase (JNK) phosphorylation, suggesting an activation of necroptosis and apoptosis, respectively. These results suggest that QUIN activates the autophagy, but on day 7, it is blocked and organelle and cellular damage, neurodegeneration, and behavior alterations could be caused by necroptosis and apoptosis activation.