Tranexamic acid versus adrenaline-soaked pledgets for the reduction of intraoperative bleeding in functional endoscopic sinus surgery.

OBJECTIVE: Aim: To examine the impact of locally applied tranexamic acid and adrenaline, separately and in combination, on intraoperative blood loss and surgical field quality during functional endoscopic sinus surgery. PATIENTS AND METHODS: Materials and Methods: The study involved 40 patients with chronic rhinosinusitis. They were divided into two groups. Group I received adrenaline alone in one side and a mixture of adrenaline and tranexamic acid in the other side. Group II received adrenaline alone in one side and tranexamic acid in the otherside. Parameters like surgery time, blood loss, and surgical field quality were studied. RESULTS: Results: In Group I, the combination of adrenaline and tranexamic acid significantly reduced blood loss and enhanced surgical field quality compared to adrenaline alone. In Group II, adrenaline outperformed tranexamic acid in shortening surgery duration and improving surgical field quality. However, there was no significant difference in blood loss reduction between adrenaline and tranexamic acid. CONCLUSION: Conclusions: The study concluded that tranexamic acid is less effective than adrenaline when introduced as topical intranasal pledgets in both decreasing the time needed for the surgery and improving the subjective satisfaction of the surgeon while there is no significant difference regarding decreasing intraoperative blood loss. The mixture of adrenaline and tranexamic acid pledgets are more effective than adrenaline-only pledgets in terms of decreasing the intraoperative blood loss and improving the surgeon's satisfaction with no significant difference regarding the time needed for the surgery.

Knowledge and attitude of Palestinian women to contraceptives: a cross-sectional study.

BACKGROUND: Contraceptives have documented efficiency, but outcomes are highly dependent on women's understanding of how they should be used. We assessed the knowledge and attitudes of married Palestinian women about contraceptives and understanding of use of the available methods and side-effects. METHODS: This cross-sectional study involved married Palestinian women of childbearing age (18-50 years), and was done between Jan 20, 2017, and Jan, 1, 2018. A stratified random sample of 900 women was selected from each Palestinian governorate in the West Bank and East Jerusalem, with the number selected based on population size. An interviewer-assisted questionnaire was completed by each participant. FINDINGS: 833 women were selected to participate and 771 (93%) completed the questionnaire. 123 (16%) of women reported not using any method of contraception. Among those who used contraception, intrauterine devices were most commonly used (312 [41%] of 771), followed by oral contraceptives (162 [21%]). Progestagen-only pills were the most frequently used type of oral contraceptive (45 [28%] of 162). Female sterilisation was used as a birth control method by 19 (3%) of 771 women. Investigation of the reasons behind contraception use showed that organisation of pregnancies was most common (511 [79%] of 648), followed by having too many children (131 [20%]) and economic reasons (73 [11%]). Regarding attitudes and beliefs towards contraceptive use, of the 771 participants, 49 (6%) believed that religion forbids their use and 112 (14·5%) considered them socially unacceptable. The study revealed poor scores for knowledge about use and possible side effects of contraceptives (mean 8·2 [SD 2·9] correct answers to 14 questions). INTERPRETATION: Most Palestinian women have used contraceptives, but poor knowledge of how to use them and side-effects is apparent. The attitudes of Palestinian women and their partners towards contraceptives indicates general acceptance of their use. A strength of our study is that it included representative sample of Palestinian women and our results and conclusions reflect the knowledge and attitudes towards contraceptives in Palestinian society. FUNDING: None.

A systematic review of interventions to reduce anticholinergic burden in older people with dementia in primary care.

OBJECTIVE: This systematic review aimed to assess the types and effectiveness of interventions that sought to reduce anticholinergic burden (ACB) in people with dementia (PwD) in primary care. METHODS: One trial registry and eight electronic databases were systematically searched to identify eligible English language studies from inception until December 2021. To be eligible for inclusion, studies had to be randomised controlled trials (RCTs) or non-randomised studies (NRS), including controlled before-and-after studies and interrupted time-series studies, of interventions to reduce ACB in PwD aged ≥65 years (either community-dwelling or care home residents). All outcomes were to be considered. Quality was to be assessed using the Cochrane Risk of Bias tool for RCTs and ROBINS-I tool for NRS. If data could not be pooled for meta-analysis, a narrative synthesis was to be conducted. RESULTS: In total, 1880 records were found, with 1594 records remaining after removal of duplicates. Following title/abstract screening, 13 full-text articles were assessed for eligibility. None of these studies met the inclusion criteria for this review. Reasons for exclusion were incorrect study design, ineligible study population, lack of focus on reducing ACB, and studies conducted outside the primary care setting. CONCLUSIONS: This 'empty' systematic review highlights the lack of interventions to reduce ACB in PwD within primary care, despite this being highlighted as a priority area for research in recent clinical guidance. Future research should focus on development and testing of interventions to reduce ACB in this patient population through high-quality clinical trials.

The association between early MRI and length of disability in acute lower back pain: a systematic review and narrative synthesis.

BACKGROUND: Clinical guideline recommendations are against early magnetic resonance imaging (eMRI) within the first 4 to 6 weeks of conservative management of acute low back pain (LBP) without "clinical suspicion" of serious underlying conditions (red flags). There is some limited evidence that a significant proportion of patients with LBP receive eMRI non- indicated by clinical guidelines, which could be associated with increased length of disability (LOD). The aim of this systematic review was to investigate whether eMRI for acute LBP without red flags is associated with increased LOD. The LOD was defined as the number of disability days (absence from work). METHODS: Medline, EMBASE, and CINAHL bibliographic databases were searched from inception until June 5, 2021. Two reviewers independently assessed the methodological quality of included studies using the Newcastle-Ottawa scale and extracted data for the review. The search identified 324 records, in which seven studies met the inclusion criteria. Three of the included studies used the same study population. Owing to between-study heterogeneity, a narrative synthesis of results was used. RESULTS: All included studies were of good methodological quality and consistently reported that patients with acute LBP without red flags who received eMRI had increased LOD compared to those who did not receive eMRI. Three retrospective cohort studies reported that the eMRI groups had a higher mean LOD than the no eMRI groups ranging from 9.4 days (95% CI 8.5, 10.2) to 13.7 days (95% CI 13.0, 14.5) at the end of 1-year follow-up period. The remaining studies reported that the eMRI groups had a higher hazard ratio of work disability ranging between 1.75 (95% CI 1.23, 2.50) and 3.57 (95% CI 2.33, 5.56) as compared to the no eMRI groups. CONCLUSION: eMRI is associated with increased LOD in patients with acute LBP without red flags. Identifying reasons for performing non-indicated eMRI and addressing them with quality improvement interventions may improve adherence to clinical guidelines and improve disability outcomes among patients with LBP.

Assessment of sexual and reproductive health knowledge and awareness among single unmarried women living in Lebanon: a cross-sectional study.

BACKGROUND: Sexual and reproductive health (SRH), a globally recognized fundamental health concern and a basic human right is poorly addressed and seldom researched in the Arab world. Disregarding this aspect of health creates various obstacles to accessing SRH related services and education. This threatens the health of a female, namely through increasing the probability of unplanned pregnancies and unsafe abortions, augmenting the risk of acquiring sexually transmitted infections, and most importantly, increasing the hazard of maternal and neonatal death. Thus, this study aimed to assess the level of SRH related knowledge and awareness among single unmarried women living in Lebanon. METHODS: A descriptive cross-sectional study design was conducted using a self-administered questionnaire in both English and Arabic languages. The questionnaire included 9 sections; socio-demographic characteristics section, sexually transmitted infections (STIs) section, premarital tests section, vaccines section, menstruation and its abnormalities section, pregnancy symptoms and identification section, methods of contraception section, vitamins section, and honeymoon events section. The questionnaire was distributed among all Lebanese governorates to 491 single unmarried women living in Lebanon aged between 17 and 55 years. Student t-test and Chi-Square test were used to analyze results. RESULTS: It was found that only 8.8% of all the participants had adequate knowledge. The highest level of SRH related knowledge was about pregnancy (88.0%), and the least was about contraception (13.5%). Most of the knowledgeable participants lived in Beirut governorate (13.6%, n = 8) and had reached universities (10.3%, n = 41), but this was not statistically significant (p-value > 0.05). The effect of a prior visit to a gynecologist was statistically non-significant on the overall level of knowledge (p-value = 0.269). CONCLUSION: Due to the inadequate level of knowledge, SRH education campaigns empowered by the Ministry of Public Health in collaboration with primary care physicians and gynecologists, are recommended in both the societal and academic sectors to enhance the awareness level and make SRH knowledge readily available among unmarried women aged between 17 and 55. Knowing the massive role of social media nowadays, the messages they present should contribute to enhancing the level of SRH knowledge and redirect attitudes and behaviors of unmarried females in Lebanon.

A minimal synaptic model for direction selective neurons in Drosophila.

Visual motion estimation is a canonical neural computation. In Drosophila, recent advances have identified anatomic and functional circuitry underlying direction-selective computations. Models with varying levels of abstraction have been proposed to explain specific experimental results but have rarely been compared across experiments. Here we use the wealth of available anatomical and physiological data to construct a minimal, biophysically inspired synaptic model for Drosophila's first-order direction-selective T4 cells. We show how this model relates mathematically to classical models of motion detection, including the Hassenstein-Reichardt correlator model. We used numerical simulation to test how well this synaptic model could reproduce measurements of T4 cells across many datasets and stimulus modalities. These comparisons include responses to sinusoid gratings, to apparent motion stimuli, to stochastic stimuli, and to natural scenes. Without fine-tuning this model, it sufficed to reproduce many, but not all, response properties of T4 cells. Since this model is flexible and based on straightforward biophysical properties, it provides an extensible framework for developing a mechanistic understanding of T4 neural response properties. Moreover, it can be used to assess the sufficiency of simple biophysical mechanisms to describe features of the direction-selective computation and identify where our understanding must be improved.

Impact of nitrogen source and supply level on growth, yield and nutritional value of two contrasting ecotypes of Cichorium spinosum L. grown hydroponically.

BACKGROUND: In the present study, two contrasting stamnagathi (Cichorium spinosum L.) ecotypes originating either from a mountainous or from a seaside habitat were grown hydroponically and supplied with a nutrient solution differing in the total-N level (4 or 16 mmol L-1 ) and the N source (NH4+ -N/total-N: 0.05, 0.25 or 0.50). The aim was to search for genotypic differences in nitrogen nutrition. RESULTS: At commercial maturity, the dry weight of mountainous plants was higher than that of seaside plants. The shoot mineral concentrations were higher in seaside plants than in mountainous plants in both harvests. The leaf nitrate concentration was influenced by the levels of both total-N and NH4+ -N/total-N at both harvests, whereas plants with a seaside origin exhibited higher nitrate concentrations than those originating from a mountainous site in all total-N and NH4+ -N/total-N treatments. CONCLUSION: The two stamnagathi ecotypes differed considerably in their responses to nitrogen nutrition and tissue nitrate content. The mountainous ecotype was superior in terms of growth, tissue nitrate concentration and antioxidant capacity, whereas the seaside ecotype accumulated more nutrient microcations in leaves. A low total-N concentration (up to 4 mmol L-1 ) combined with a high NH4+ -N/total-N ratio (up to 0.05) could minimize tissue NO3- concentrations without compromising yield. © 2017 Society of Chemical Industry.

The effect of vitamin D supplementation on knee osteoarthritis, the VIDEO study: a randomised controlled trial.

OBJECTIVE: Epidemiological data suggest low serum 25-hydroxyvitamin D3 (25-OH-D3) levels are associated with radiological progression of knee osteoarthritis (OA). This study aimed to assess whether vitamin D supplementation can slow the rate of progression. METHOD: A 3-year, double-blind, randomised, placebo-controlled trial of 474 patients aged over 50 with radiographically evident knee OA comparing 800 IU cholecalciferol daily with placebo. Primary outcome was difference in rate of medial joint space narrowing (JSN). Secondary outcomes included lateral JSN, Kellgren & Lawrence grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, stiffness and the Get up and Go test. RESULTS: Vitamin D supplementation increased 25-OH-D3 from an average of 20.7 (standard deviation (SD) 8.9) µg/L to 30.4 (SD 7.7) µg/L, compared to 20.7 (SD 8.1) µg/L and 20.3 (SD 8.1) µg/L in the placebo group. There was no significant difference in the rate of JSN over 3 years in the medial compartment of the index knee between the treatment group (average -0.01 mm/year) and placebo group (-0.08 mm/year), average difference 0.08 mm/year (95% confidence interval (CI) [-0.14-0.29], P = 0.49). No significant interaction was found between baseline vitamin D levels and treatment effect. There were no significant differences for any of the secondary outcome measures. CONCLUSION: Vitamin D supplementation did not slow the rate of JSN or lead to reduced pain, stiffness or functional loss over a 3-year period. On the basis of these findings we consider that vitamin D supplementation has no role in the management of knee OA.

Relationship Between Cognitive Assessment and Balance Measures in Adolescents Referred for Vestibular Physical Therapy After Concussion.

OBJECTIVE: To examine the relationship between cognitive and balance performance in adolescents with concussion. DESIGN: Retrospective case series. SETTING: Tertiary. PATIENTS: Sixty patients. INTERVENTIONS: Correlation analyses were performed to describe the relationship between symptoms, cognitive measure, and balance measure at the time of initiation of vestibular physical therapy. MAIN OUTCOME MEASURES: Cognitive performance was assessed using the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT). The dizziness and balance function measures included dizziness severity rating, Activities-specific Balance Confidence scale (ABC), Dizziness Handicap Inventory (DHI), Functional Gait Assessment, gait speed, Timed "UP and GO," Five Times Sit to Stand, and Sensory Organization Test (SOT). To account for multiple comparisons, the False Discovery Rate method was used. RESULTS: Performance measures of balance were significantly correlated with cognitive measures. Greater total symptom scores were related to greater impairment in the ABC and DHI (r = 0.35-0.39, P ≤ 0.008) and worse performance in condition 2 of the SOT (r = -0.48, P = 0.004). Among the ImPACT composite scores, lower memory scores were correlated with impaired balance performance measures (r = 0.37-0.59, P ≤ 0.012). Lower visual memory was also correlated with worse ABC scores. CONCLUSIONS: The significant relationships reported between the cognitive performance scores and balance measures may reflect that similar levels of functioning exist across domains in individuals with protracted recovery who receive vestibular physical therapy. CLINICAL RELEVANCE: The weak-to-moderate relationships warrant the continuous use of multiple domains of assessment. A better understanding to the relationships between the domains of functioning after concussion may improve the overall management approach for adolescents with concussion.

Performance of high school adolescents on functional gait and balance measures.

PURPOSE: To describe the performance of high school adolescents during common functional gait and balance measures used in vestibular physical therapy. METHODS: A cross-sectional study of 91 participants determined their performance on the Activities-specific Balance Confidence (ABC) scale, Dynamic Gait Index, Functional Gait Assessment, Timed "Up and Go" (TUG), Five Times Sit to Stand (FTSTS) test, tests of gait speed (GS), and the Balance Error Scoring System. In a subset of this sample, GS, TUG, and the FTSTS were repeated twice to examine test-retest reliability. RESULTS: The measures of GS, TUG, and FTSTS were normally distributed. The Activities-specific Balance Confidence, Dynamic Gait Index, and Functional Gait Assessment exhibited a ceiling effect. The timed measures exhibited moderate to good reliability. CONCLUSIONS: These performance scores may provide end points for discharge from vestibular physical therapy. However, clinicians should be aware of the ceiling effect exhibited by some measures.

Influence of overlay strength degradation on bond stresses of bridge deck system.

This research paper intends to numerically investigate the impact of selected factors on the strength of the concrete overlay-bridge deck bond, directly and indirectly, using the nonlinear finite element analysis (NLFEA) method. Besides, the research introduces the guidelines necessary to attain adequate bond strength to eliminate the possibility of concrete detachment under the effect of different developed stresses. The NLFEA has been utilized in predicting and correlating the live applied loads and the induced shrinkage stresses at the interfacial region between the concrete overlay and the bridge deck. The developed stresses were related to the overlay's direct tensile bond strength. A total of 336 NLFEA models of overlay-bridge deck slab segments were designed and examined after being properly validated. The parameters of the study were as follows: the overlay degradation level (0 %, 19 %, 36 %, 51 %, 64 %, and 75 %); the ratio of the overlay's relative thickness-to-the bridge deck slab (toverlay/tslab); in addition to the age of the shrinkage induced stresses (early age (3 and 7 days) and moderate age (14 and 28 days)). The NLFEA live load and shrinkage stress values were validated using experimental results from the literature with difference percentages of less than 5 %. The numerical study results recommended that the thickness of the concrete's overlay should be within certain overlay thickness limits to be capable of handling the lower and higher stresses at the service and overloading conditions. The proposed guidelines enable the avoidance of unfavorable detachment between the interface parts under the effect of AASHTO HS-20 truck cyclic and impact loadings, as well as shrinkage loading.

Surgical Written Consent in Aesthetic Plastic Surgery: A Plastic Center Audit of Surgical Consent Standards.

Background Informed consent is a fundamental aspect of modern medical practice that requires effective communication and an ample understanding of medical ethics, patient autonomy, and the legal obligations of healthcare professionals. Maintaining high-quality surgical informed consent is a crucial step in the healthcare process. Thus, we aimed to obtain surgical written consent on abdominoplasty, suction-assisted abdominal dermo lipectomy, and lower body lifting from our hospital database over three months (January to March, 2023) to assess our level across the American Society of Plastic Surgeons (ASPS) system. Results A total of 45 surgical written consents were obtained and 37 consents remained after exclusion. Bleeding, infection, and hematoma were mentioned in more than 80% of our consents. However, important complications such as ileus and umbilical malposition were never mentioned. Overall, the completion rate of written complications ranged from 14% to 56% in comparison to data from the ASPS. Conclusions Our results show a measurable inconsistency in surgical written consents at our center. Thus, establishing a comprehensive and accurate surgical written consent will aid in protecting our center against deficient surgical written consent accusations, improve the experience of patients, and enhance the quality of service provided by our center.

Intra-biliary hydatid cyst rupture: A rare case report with superinfection.

Key Clinical Message: Hydatid cysts, primarily found in the liver (70%), are caused by parasitic infections and can lead to severe complications such as cyst rupture. This case report describes a unique instance of a hydatid liver cyst occupying the right lobe with a communicating part with the biliary tree that ruptured showing a concurrent superinfection. Abstract: Hydatid cysts are a clinical pathology resulting from parasitic infections. They may occur in different organs of the body. However, these are mostly found in the liver (70%). This can cause significant complications including cyst rupture. Several case reports have described various hydatid cyst ruptures; however, only a few have reported an intra-biliary hydatid cyst rupture. A 24-year-old male patient presented with right upper quadrant pain, jaundice, dark urine, and pale stool. Imaging studies, including Magnetic resonance cholangiopancreatography (MRCP) and computed tomography (CT), revealed a beavertail liver, cystobiliary communication and intrahepatic biliary tree-ruptured hydatid cysts. The cyst was in the right liver lobe, which is the most common site for hydatid cysts. Surgical intervention involving laparoscopic de-roofing and cyst removal resulted in a smooth recovery without complications. Several case reports have described various hydatid cyst ruptures; however, only a few have reported originally placed intra-biliary hydatid cyst ruptures. This case report describes a unique instance of a hydatid liver cyst occupying the right lobe with a communicating part with the biliary tree that ruptured showing a concurrent superinfection.

Prognostic factors and predictive models in hot gallbladder surgery: A prospective observational study in a high-volume center.

Backgrounds/Aims: The standard treatment for acute cholecystitis, biliary pancreatitis and intractable biliary colics ("hot gallbladder") is emergency laparoscopic cholecystectomy (LC). This paper aims to identify the prognostic factors and create statistical models to predict the outcomes of emergency LC for "hot gallbladder." Methods: A prospective observational cohort study was conducted on 466 patients having an emergency LC in 17 months. Primary endpoint was "suboptimal treatment," defined as the use of escape strategies due to the impossibility to complete the LC. Secondary endpoints were postoperative morbidity and length of postoperative stay. Results: About 10% of patients had a "suboptimal treatment" predicted by age and low albumin. Postop morbidity was 17.2%, predicted by age, admission day, and male sex. Postoperative length of stay was correlated to age, low albumin, and delayed surgery. Conclusions: Several predictive prognostic factors were found to be related to poor emergency LC outcomes. These can be useful in the decision-making process and to inform patients of risks and benefits of an emergency vs. delayed LC for hot gallbladder.

Necrotizing Soft Tissue Infection Post VASER-Assisted Liposuction and Lipofilling: A Case Report.

Liposuction is a very common aesthetic procedure nowadays. The complication rate is very minimal, and it increases relatively when combined with other procedures. Infection is an expected complication in liposuction and its risk is below 1% in isolated procedures. Although the risk is very low, it might lead to fatal consequences. In this manuscript, the authors present a previously healthy female who presented to the authors' emergency department post-vibration amplification of sound energy at resonance (VASER)-assisted liposuction and lipofilling done in a private center. Her signs and symptoms started after the procedure and she visited the private center multiple times; however, no significant improvement was felt. Upon her presentation to the authors' facility, immediate resuscitation was initiated, and she was admitted for further investigations and management. Despite all resuscitation efforts and interventions, the patient's condition kept deteriorating. She was admitted to the surgical intensive care unit and taken to the operating theater twice with no observed significant improvement. The patient developed septic shock, a multiorgan failure state, followed by cardiac arrest. All resuscitation measures were taken, but the patient could not be revived and was declared dead. Early recognition of signs and symptoms of infection could be lifesaving. Aggressive resuscitation and surgical interventions (extensive debridement and antibiotics) might be necessary to produce successful outcomes.

The association between mobile phone use and neuromusculoskeletal complaints.

BACKGROUND: Mobile phones have become an essential component in our life. There are many concerns about the effects of prolonged mobile phone use on the upper extremity. OBJECTIVE: This research aims to investigate the effects of prolonged mobile phone use on the neuromusculoskeletal system of the upper extremity in young adults in Jordan. METHODS: A total of 228 subjects (age = 20.7±1.27 years) participated in this study. A structured questionnaire was used to collect data on sociodemographic variables, mobile phone size, hand/finger used for typing, duration of use daily, and the presence of musculoskeletal pain/syndromes and their location. RESULTS: Statistically significant relations (p < 0.05) were found between the prolonged use of mobile phones and self-reported pain in neck/upper back, hands, and symptoms of cubital syndrome; between smaller hand-to-phone ratio and pain in neck/upper back and shoulders with the higher frequency of pain in females. Females and subjects with a smaller hand-to-phone ratio tend to use two hands (p < 0.05). CONCLUSION: The results show an association between mobile phone use and self-reported pain. This study provides guidance for mobile phone manufacturers and regulatory agencies on the potential effects, the need for awareness programs that alert to musculoskeletal complaints, choosing the appropriate mobile phone, and changing using habits. Further investigations on a larger sample with quantitative measures on the kinematics and muscular activities are necessary to generalize and better interpret the results.

Synthesis, Molecular Modeling and Biological Evaluation of Novel Trifluoromethyl Benzamides as Promising CETP Inhibitors.

BACKGROUND: Hyperlipidemia is considered a major risk factor for the progress of atherosclerosis. OBJECTIVE: Cholesteryl ester transfer protein (CETP) facilitates the relocation of cholesterol esters from HDL to LDL. CETP inhibition produces higher HDL and lower LDL levels. METHODS: Synthesis of nine benzylamino benzamides 8a-8f and 9a-9c was performed. RESULTS: In vitro biological study displayed potential CETP inhibitory activity, where compound 9c had the best activity with an IC50 of 1.03 µM. Induced-fit docking demonstrated that 8a-8f and 9a-9c accommodated the CETP active site and hydrophobic interaction predominated ligand/ CETP complex formation. CONCLUSION: Pharmacophore mapping showed that this scaffold endorsed CETP inhibitors features and consequently elaborated the high CETP binding affinity.

Machine learning approaches to predict drug efficacy and toxicity in oncology.

In recent years, there has been a surge of interest in using machine learning algorithms (MLAs) in oncology, particularly for biomedical applications such as drug discovery, drug repurposing, diagnostics, clinical trial design, and pharmaceutical production. MLAs have the potential to provide valuable insights and predictions in these areas by representing both the disease state and the therapeutic agents used to treat it. To fully utilize the capabilities of MLAs in oncology, it is important to understand the fundamental concepts underlying these algorithms and how they can be applied to assess the efficacy and toxicity of therapeutics. In this perspective, we lay out approaches to represent both the disease state and the therapeutic agents used by MLAs to derive novel insights and make relevant predictions.

Long timescale anti-directional rotation in Drosophila optomotor behavior.

Locomotor movements cause visual images to be displaced across the eye, a retinal slip that is counteracted by stabilizing reflexes in many animals. In insects, optomotor turning causes the animal to turn in the direction of rotating visual stimuli, thereby reducing retinal slip and stabilizing trajectories through the world. This behavior has formed the basis for extensive dissections of motion vision. Here, we report that under certain stimulus conditions, two Drosophila species, including the widely studied D. melanogaster, can suppress and even reverse the optomotor turning response over several seconds. Such "anti-directional turning" is most strongly evoked by long-lasting, high-contrast, slow-moving visual stimuli that are distinct from those that promote syn-directional optomotor turning. Anti-directional turning, like the syn-directional optomotor response, requires the local motion detecting neurons T4 and T5. A subset of lobula plate tangential cells, CH cells, show involvement in these responses. Imaging from a variety of direction-selective cells in the lobula plate shows no evidence of dynamics that match the behavior, suggesting that the observed inversion in turning direction emerges downstream of the lobula plate. Further, anti-directional turning declines with age and exposure to light. These results show that Drosophila optomotor turning behaviors contain rich, stimulus-dependent dynamics that are inconsistent with simple reflexive stabilization responses.

Neural mechanisms to incorporate visual counterevidence in self motion estimation.

In selecting appropriate behaviors, animals should weigh sensory evidence both for and against specific beliefs about the world. For instance, animals measure optic flow to estimate and control their own rotation. However, existing models of flow detection can confuse the movement of external objects with genuine self motion. Here, we show that stationary patterns on the retina, which constitute negative evidence against self rotation, are used by the fruit fly Drosophila to suppress inappropriate stabilizing rotational behavior. In silico experiments show that artificial neural networks optimized to distinguish self and world motion similarly detect stationarity and incorporate negative evidence. Employing neural measurements and genetic manipulations, we identified components of the circuitry for stationary pattern detection, which runs parallel to the fly's motion- and optic flow-detectors. Our results exemplify how the compact brain of the fly incorporates negative evidence to improve heading stability, exploiting geometrical constraints of the visual world.