Search

Summary: The anaesthetist aims to preserve normal physiology of the horse notwithstanding the use of general anaesthetic drugs and pre‐existing pathological changes. Provision of analgesia and maintaining an adequate plane of anaesthesia are important alongside monitoring cardiorespiratory performance, response to noxious stimuli and temperature. There are a variety of techniques that subjectively or objectively assess physiological variables, and the results should be interpreted in the context of the anaesthetic protocol. Basic 'hands‐on' monitoring of anaesthesia requires no equipment and is a core skill for every anaesthetist. However, as technology advances, many more electronic monitoring options have become available. This review describes how to use specific monitoring techniques, discusses the evidence underpinning them and evaluates their place in clinical practice. Where appropriate, normal and abnormal values are highlighted, although evaluation of trends may be more important in some cases. Regular documentation of variables enables trends to be identified and is key to appropriate early intervention. All basic monitoring techniques that require no equipment, such as ocular and mucous membrane assessment and pulse palpation, are recommended for every general anaesthetic procedure. The use of capnography, pulse oximetry, electrocardiography and blood pressure monitoring devices is recommended where indicated (Martinez et al., 2008), recognising that anaesthesia in horses is performed in a variety of places with different facilities and using various drug combinations. [ABSTRACT FROM AUTHOR]

Decision-making processes can be modulated by stress, and the time elapsed from stress induction seems to be a crucial factor in determining the direction of the effects. Although current approaches consider the first post-stress hour a uniform period, the dynamic pattern of activation of the physiological stress systems (i.e., the sympathetic nervous system and hypothalamic-pituitary-adrenal axis) suggests that its neurobehavioural impact might be heterogeneous. Here, we evaluate economic risk preferences on the gain domain (i.e., risk aversion) at three time points following exposure to psychosocial stress (immediately after, and 20 and 45 min from onset). Using lottery games, we examine decisions at both the individual and social levels. We find that risk aversion shows a time-dependent change across the first post-stress hour, evolving from less risk aversion shortly after stress to more risk averse behaviour at the last testing time. When risk implied an antisocial outcome to a third party, stressed individuals showed less regard for this person in their decisions. Participants' cortisol levels explained their behaviour in the risk, but not the antisocial, game. Our findings reveal differential stress effects in self- and other-regarding decision-making and highlight the multidimensional nature of the immediate aftermath of stress for cognition. [ABSTRACT FROM AUTHOR]

Scientific discoveries often hinge on synthesizing decades of research, a task that potentially outstrips human information processing capacities. Large language models (LLMs) offer a solution. LLMs trained on the vast scientific literature could potentially integrate noisy yet interrelated findings to forecast novel results better than human experts. Here, to evaluate this possibility, we created BrainBench, a forward-looking benchmark for predicting neuroscience results. We find that LLMs surpass experts in predicting experimental outcomes. BrainGPT, an LLM we tuned on the neuroscience literature, performed better yet. Like human experts, when LLMs indicated high confidence in their predictions, their responses were more likely to be correct, which presages a future where LLMs assist humans in making discoveries. Our approach is not neuroscience specific and is transferable to other knowledge-intensive endeavours., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Introduction: In the early days of the COVID-19 pandemic, individuals were asked to perform costly actions to reduce harm to strangers, even while the general population, including authorities and experts, grappled with the uncertainty surrounding thenovel virus. Many studies have examined health decision-making by experts, but the study of lay, non-expert, individual decision-making on a stranger's health has been left to the wayside, as ordinary citizens are usually not tasked with such decisions., Methods: We sought to capture a snapshot of this specific choice behavior by administering two surveys to the general population in the spring of 2020, when much of the global community was subject to COVID-19-related restrictions, as well as uncertainty surrounding the virus. We presented study participants with fictitious diseases varying in severity that threatened oneself, a loved one or a stranger. Participants were asked to choose between treatment options that could either provide a sure, but mild improvement (sure option) or cure the affected person at a given probability of success (risky option)., Results: Respondents preferred gambles overall, but risk-seeking decreased progressively with higher expected severity of disease. This pattern was observed regardless of the recipient's identity. Distinctions between targets emerged however whendecisions were conditioned on a treatment's monetary cost, with participants preferring cheaper options for strangers., Discussion: Overall, these findings provide a descriptive model of individual decision-making under risk for others; and inform on the limits of what can be asked of an individual in service to a stranger., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Loued-Khenissi and Corradi-Dell’Acqua.)

Does gravity affect decision-making? This question comes into sharp focus as plans for interplanetary human space missions solidify. In the framework of Bayesian brain theories, gravity encapsulates a strong prior, anchoring agents to a reference frame via the vestibular system, informing their decisions and possibly their integration of uncertainty. What happens when such a strong prior is altered? We address this question using a self-motion estimation task in a space analog environment under conditions of altered gravity. Two participants were cast as remote drone operators orbiting Mars in a virtual reality environment on board a parabolic flight, where both hyper- and microgravity conditions were induced. From a first-person perspective, participants viewed a drone exiting a cave and had to first predict a collision and then provide a confidence estimate of their response. We evoked uncertainty in the task by manipulating the motion's trajectory angle. Post-decision subjective confidence reports were negatively predicted by stimulus uncertainty, as expected. Uncertainty alone did not impact overt behavioral responses (performance, choice) differentially across gravity conditions. However microgravity predicted higher subjective confidence, especially in interaction with stimulus uncertainty. These results suggest that variables relating to uncertainty affect decision-making distinctly in microgravity, highlighting the possible need for automatized, compensatory mechanisms when considering human factors in space research., (© 2023. The Author(s).)

Objectives: To record the success rate of veterinary professionals and students at identifying the pulse in conscious and anaesthetized dogs. To explore the influence of clinical experience, pulse location, anaesthesia and likely confounding variables on the success of pulse palpation., Study Design: Prospective, observational, randomized study., Animals: A total of 54 client-owned dogs scheduled for general anaesthesia., Methods: For each dog, three participants (senior anaesthetist, anaesthesia resident/nurse, veterinary student/animal care assistant) attempted pulse palpation at three locations (femoral, radial and dorsal pedal pulse) in conscious and anaesthetized dogs. The time to pulse palpation was measured with a stopwatch for each attempt and data were modelled using a multivariate Cox regression survival analysis (significance p < 0.05)., Results: The overall success rate of pulse palpation was 77%, with a median time of 10.91 seconds (interquartile range 9.09 seconds). Success rate was lower in conscious dogs (67%) than in anaesthetized dogs (87%). There was a 77% lower likelihood of success at the radial than at the femoral pulse [hazard ratio (HR) 0.23, 95% confidence interval (CI) 0.38-0.69, p < 0.001]. Veterinary students/animal care assistants had a 71% lower likelihood of success than senior anaesthetists (HR 0.29, 95% CI 0.22-0.39, p < 0.001). Age, weight and American Society of Anesthesiologists physical status had no significant influence. Premedication/anaesthetic drugs, heart rate or mean arterial pressure had no significant influence on the time to pulse palpation in anaesthetized dogs. The median time to palpation was less than 10 seconds for all experience groups at the femoral location., Conclusions: Palpation of the femoral location had the greatest likelihood of success with the least amount of time. Monitoring the femoral pulse during induction of anaesthesia is suggested as a method for confirming spontaneous circulation. Pulse palpation improves with clinical experience., (Copyright © 2022 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Socioeconomic status (SES) plays a significant role in health and disease. At the same time, early-life conditions affect neural function and structure, suggesting the brain may be a conduit for the biological embedding of SES. Here, we investigate the brain anatomy signatures of SES in a large-scale population cohort aged 45-85 years. We assess both gray matter morphometry and tissue properties indicative of myelin content. Higher life course SES is associated with increased volume in several brain regions, including postcentral and temporal gyri, cuneus, and cerebellum. We observe more widespread volume differences and higher myelin content in the sensorimotor network but lower myelin content in the temporal lobe associated with childhood SES. Crucially, childhood SES differences persisted in adult brains even after controlling for adult SES, highlighting the unique contribution of early-life conditions to brain anatomy, independent of later changes in SES. These findings inform on the biological underpinnings of social inequality, particularly as they pertain to early-life conditions., (© 2022 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

Background: Estimating others' pain is a challenging inferential process, associated with a high degree of uncertainty. While much is known about uncertainty's effect on self-regarding actions, its impact on other-regarding decisions for pain have yet to be characterized., Aim: The present study exploited models of probabilistic decision-making to investigate how uncertainty influences the valuation and assessment of another's pain., Materials & Methods: We engaged 63 dyads (43 strangers and 20 romantic couples) in a task where individual choices affected the pain delivered to either oneself (the agent) or the other member of the dyad. At each trial, agents were presented with cues predicting a given pain intensity with an associated probability of occurrence. Agents either chose a sure (mild decrease of pain) or risky (50% chance of avoiding pain altogether) management option, before bidding on their choice. A heat stimulation was then issued to the target (self or other). Decision-makers were then asked to rate the pain administered to the target., Results: We found that the higher the expected pain, the more risk-averse agents became, in line with findings in value-based decision-making. Furthermore, agents gambled less on another individual's pain (especially strangers) and placed higher bids on pain relief than they did for themselves. Most critically, the uncertainty associated with expected pain dampened ratings made for strangers' pain. This contrasted with the effect on an agent's own pain, for which risk had a marginal hyperalgesic effect., Discussion & Conclusion: Overall, our results suggested that risk selectively affects decision-making on a stranger's suffering, both at the level of assessment and treatment selection, by (1) leading to underestimation, (2) privileging sure options and (3) altruistically allocating more money to insure the treatment's success., Significance: Uncertainty biases decision-making but it is unclear if it affects choice behavior on pain for others. In examining this question, we found individuals were generally risk-seeking when faced with looming pain, but more so for self; and assigned higher monetary values and subjective ratings on another's pain. However, uncertainty dampened agents' assessment of a stranger's pain, suggesting latent variables may contradict overt altruism. This bias may underlie pain underestimation in clinical settings., (© 2022 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC ®.)

Given the controversy about the impact of modifiable risk factors on mood and cognition in ageing, we sought to investigate the associations between cardio-vascular risk, mental health, cognitive performance and brain anatomy in mid- to old age. We analyzed a set of risk factors together with multi-parameter magnetic resonance imaging (MRI) in the CoLaus|PsyCoLaus cohort (n > 1200). Cardio-vascular risk was associated with differences in brain tissue properties - myelin, free tissue water, iron content - and regional brain volumes that we interpret in the context of micro-vascular hypoxic lesions and neurodegeneration. The interaction between clinical subtypes of major depressive disorder and cardio-vascular risk factors showed differential associations with brain structure depending on individuals' lifetime trajectory. There was a negative correlation between melancholic depression, anxiety and MRI markers of myelin and iron content in the hippocampus and anterior cingulate. Verbal memory and verbal fluency performance were positively correlated with left amygdala volumes. The concomitant analysis of brain morphometry and tissue properties allowed for a neuro-biological interpretation of the link between modifiable risk factors and brain health., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

The temporo-parietal junction (TPJ) consistently emerges in other-regarding behavior, including tasks probing affective phenomena such as morality and empathy. Yet the TPJ is also recruited in processes with no affective or social component, such as visuo-spatial processing and mathematical cognition. We present serendipitous findings from a perceptual decision-making task on a bistable stimulus, the Necker Cube, performed in an MRI scanner. The stimulus in question is a transparent, wire-frame cube that evokes spontaneous switches in perception. Individuals can view the cube from below or from above, though a consistent bias is shown towards seeing the cube from above. We replicate this bias, finding participants spend more time in the from-above percept. However, in testing for BOLD differences between percept orientations, we found robust responses in bilateral TPJ for the from-above > from-below perceptual state. We speculate that this neural response comes from the sensory incongruence of viewing an object from above while lying supine in the scanner. We further speculate that the TPJ resolves this incongruence by facilitating an egocentric projection. Such a function would explain the TPJ's ubiquitous response to other-regarding, visuo-spatial and mathematical cognition, as all these phenomena demand an ability to ambulate through the coordinate space. Our findings suggest the TPJ may not play a specific role in social or moral components of other-regarding behavior, such as altruism, and further indirectly suggest that "pure", allocentric altruism may not correlate with the TPJ. Results further have implications on how the TPJ may be modulated by activities such as flight or drone operation. Finally, this study highlights the possible need for congruence between stimuli and body position in neuroimaging studies., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The brain has been theorized to employ inferential processes to overcome the problem of uncertainty. Inference is thought to underlie neural processes, including in disparate domains such as value-based decision-making and perception. Value-based decision-making commonly involves deliberation, a time-consuming process that requires conscious consideration of decision variables. Perception, by contrast, is thought to be automatic and effortless. Both processes may call on a general neural system to resolve for uncertainty however. We addressed this question by directly comparing uncertainty signals in visual perception and an economic task using fMRI. We presented the same individuals with different versions of a bi-stable figure (Necker's cube) and with a gambling task during fMRI acquisition. We experimentally varied uncertainty, either on perceptual state or financial outcome. We found that inferential errors indexed by a formal account of surprise in the gambling task yielded BOLD responses in the anterior insula, in line with earlier findings. Moreover, we found perceptual uncertainty and surprise in the Necker Cube task yielded similar responses in the anterior insula. These results suggest that uncertainty, irrespective of domain, correlates to a common brain region, the anterior insula. These findings provide empirical evidence that the brain interacts with its environment through inferential processes., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Uncertainty presents a problem for both human and machine decision-making. While utility maximization has traditionally been viewed as the motive force behind choice behavior, it has been theorized that uncertainty minimization may supersede reward motivation. Beyond reward, decisions are guided by belief, i.e., confidence-weighted expectations. Evidence challenging a belief evokes surprise, which signals a deviation from expectation (stimulus-bound surprise) but also provides an information gain. To support the theory that uncertainty minimization is an essential drive for the brain, we probe the neural trace of uncertainty-related decision variables, namely confidence, surprise, and information gain, in a discrete decision with a deterministic outcome. Confidence and surprise were elicited with a gambling task administered in a functional magnetic resonance imaging experiment, where agents start with a uniform probability distribution, transition to a non-uniform probabilistic state, and end in a fully certain state. After controlling for reward expectation, we find confidence, taken as the negative entropy of a trial, correlates with a response in the hippocampus and temporal lobe. Stimulus-bound surprise, taken as Shannon information, correlates with responses in the insula and striatum. In addition, we also find a neural response to a measure of information gain captured by a confidence error, a quantity we dub accuracy. BOLD responses to accuracy were found in the cerebellum and precuneus, after controlling for reward prediction errors and stimulus-bound surprise at the same time point. Our results suggest that, even absent an overt need for learning, the human brain expends energy on information gain and uncertainty minimization., (Copyright © 2020 Loued-Khenissi and Preuschoff.)

Objectives Cardiorespiratory parameters and anaesthesia quality in cats anaesthetised with either intramuscular (IM) alfaxalone or ketamine both combined with dexmedetomidine and butorphanol for castration were evaluated. Methods Thirty-two client-owned cats were randomly assigned to receive either alfaxalone (A; 3 mg/kg IM) or ketamine (K; 5 mg/kg IM), combined with dexmedetomidine (10 μg/kg) and butorphanol (0.2 mg/kg). Heart rate (HR), respiratory rate (RR) and rectal temperature (T°) were recorded prior to drug administration. Pulse rate (PR) and RR were recorded 10 (T 10 ) and 15 (T 15 ) mins after injection (T 0 ). Cardiorespiratory values (PR, RR, SPO 2 , blood pressure, P E 'CO 2 ) were recorded every 5 mins for the duration of the procedure. Pain at injection, intubation and recovery were evaluated with simple descriptive scores. Feasibility of anaesthesia was evaluated by the number of top-ups of anaesthetic needed. Cat attitude, ability to walk and presence of ataxia were assessed several times after extubation (T exmin ) and the time between injection and extubation recorded. Pain was assessed at T ex120 and T ex240 with the 4Avet-pain score. Results The RR was significantly lower in group K at T 10 (RR K = 28 ±13.35 breaths per minute [brpm], RR A = 43.24 ±7.04 brpm) and T 15 (RR K = 28 ±11.53 brpm vs RR A = 43 ±12.18 brpm). Time to extubation was significantly longer in group A (T A = 62 ±14.6 mins, T K = 45.13 ± 7.38 mins). Cats in group K needed more top-ups, were more ataxic at T ex120 , had a worse recovery score at T ex60 and were less willing to walk at T ex30 . Conclusions and relevance Cats receiving alfaxalone had a longer but better quality recovery. Cardiorespiratory parameters were stable and within clinically acceptable values following IM injection of either alfaxalone or ketamine in healthy cats. Intramuscular alfaxalone is a suitable alternative to ketamine for short procedures requiring anaesthesia when used in combination with dexmedetomidine and butorphanol.

Objective: To investigate whether the use of a heat and moisture exchanger (HME) preserves body temperature in dogs weighing <10 kg anaesthetised for magnetic resonance imaging (MRI)., Study Design: Prospective, randomised, clinical trial., Animals: Thirty-one client-owned dogs., Methods: Dogs were assigned randomly to a treatment group [HME (n = 16) or no HME (n = 15)]. Dogs were pseudorandomised according to the premedication they were administered, either dexmedetomidine or no dexmedetomidine. Induction agents were not standardised. General anaesthesia was maintained with isoflurane vaporised in 100% oxygen delivered using a T-piece and a fresh gas flow of 600 mL kg -1 minute -1 . Rectal temperature was measured before premedication (T1), after induction (T2), before moving to the MRI unit (T3) and at the end of the MRI scan (T4). Ambient temperatures were measured in the induction room, outside and inside the MRI unit. Data were analysed using a general linear model with T4 as the outcome variable. Linear correlations were performed between T1, T2, T3 and T4, and variables that predicted T4 were investigated., Results: Sex, age and body mass were not significantly different between groups. There were no significant differences in rectal temperature between groups at any time point (group with HME at the end of MRI = 36.3 ± 1.1 °C; group with no HME at the end of MRI = 36.2 ± 1.4 °C) but at the end of the MRI, dogs administered dexmedetomidine (36.6 ± 0.7 °C) had a higher rectal temperature compared with dogs not administered dexmedetomidine (35.9 ± 1.6 °C) for premedication. Rectal temperature varied directly with ambient temperature in MRI scanning room and inversely with anaesthetic duration., Conclusions and Clinical Relevance: Using an HME did not alter body temperature in dogs weighing <10 kg undergoing an MRI, but including dexmedetomidine in the premedication regimen seemed to preserve the body temperature during anaesthesia., (Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.)

Purpose of Review: Mild cognitive impairment (MCI) is a comorbid factor in Parkinson's disease. The aim of this review is to examine the recent neuroimaging findings in the search for Parkinson's disease MCI (PD-MCI) biomarkers to gain insight on whether MCI and specific cognitive deficits in Parkinson's disease implicate striatal dopamine or another system., Recent Findings: The evidence implicates a diffuse pathophysiology in PD-MCI rather than acute dopaminergic involvement. On the one hand, performance in specific cognitive domains, notably in set-shifting and learning, appears to vary with dopaminergic status. On the other hand, motivational states in Parkinson's disease along with their behavioral and physiological indices suggest a noradrenergic contribution to cognitive deficits in Parkinson's disease. Finally, Parkinson's disease's pattern of neurodegeneration offers an avenue for continued research in nigrostriatal dopamine's role in distinct behaviors, as well as the specification of dorsal and ventral striatal functions., Summary: The search for PD-MCI biomarkers has employed an array of neuroimaging techniques, but still yields divergent findings. This may be due in part to MCI's broad definition, encompassing heterogeneous cognitive domains, only some of which are affected in Parkinson's disease. Most domains falling under the MCI umbrella include fronto-dependent executive functions, whereas others, notably learning, rely on the basal ganglia. Given the deterioration of the nigrostriatal dopaminergic system in Parkinson's disease, it has been the prime target of PD-MCI investigation. By testing well defined cognitive deficits in Parkinson's disease, distinct functions can be attributed to specific neural systems, overcoming conflicting results on PD-MCI. Apart from dopamine, other systems such as the neurovascular or noradrenergic systems are affected in Parkinson's disease. These factors may be at the basis of specific facets of PD-MCI for which dopaminergic involvement has not been conclusive. Finally, the impact of both dopaminergic and noradrenergic deficiency on motivational states in Parkinson's disease is examined in light of a plausible link between apathy and cognitive deficits.

Objective: Ketamine is a noncompetitive antagonist at the glutamatergic N-methyl-D-aspartate (NMDA) receptor that is used in human and animal medicine as an injectable anesthetic. The illegal use of ketamine as a recreational drug is rapidly growing. Very little is currently known about the consequences of repeated ketamine exposure in the human brain. Animal studies indicate that the prefrontal dopaminergic system is particularly vulnerable to the toxic effects of repeated administration of NMDA antagonists. In this study, dopamine D1 receptor availability was assessed by using positron emission tomography and the selective D1 receptor radioligand [11C]NNC 112 in a group of 14 recreational chronic ketamine users and matched healthy subjects., Method: History of ketamine abuse was confirmed in subjects by hair analysis. [11C]NNC 112 binding potential was measured with kinetic analysis using the arterial input function., Results: Dorsolateral prefrontal cortex D1 receptor availability was significantly up-regulated in chronic ketamine users ([11C]NNC 112 binding potential: mean=1.68 ml/g, SD=0.40) relative to comparison subjects (mean=1.35 ml/g, SD=0.35). No significant differences were noted in other cortical, limbic, or striatal regions. In the chronic ketamine user group, dorsolateral prefrontal cortex [11C]NNC 112 binding potential up-regulation was significantly correlated with the number of vials of ketamine (with a vial representing approximately 200-300 mg of ketamine) used per week., Conclusions: Chronic ketamine users exhibited a regionally selective up-regulation of D1 receptor availability in the dorsolateral prefrontal cortex, a phenomenon observed following chronic dopamine depletion in animal studies. These data suggest that the repeated use of ketamine for recreational purposes affects prefrontal dopaminergic transmission, a system critically involved in working memory and executive function.