Changing the mind? Not really—activity and connectivity in the caudate correlates with changes of choice

Changes in preference are inherently subjective and internal psychological events. We have identified brain events that presage ultimate (rather than intervening) choices, and signal the finality of a choice. At the first exposure to a pair of faces, caudate activity reflected the face of final choice, even if an initial choice was different. Furthermore, the orbitofrontal cortex and hippocampus exhibited correlations only when the subject had made a choice that would not change.     

The basolateral amygdala is necessary for negative prediction errors to enhance cue salience,but not to produce conditioned inhibition

Behavioral evidence shows that prediction errors (PEs) not only drive associative learning, but also enhance the salience of predictive cues, making them better able to capture attention when they are next encountered. Research from our laboratory suggests that this latter consequence of PEs depends on a neural circuit that includes the amygdala. Lesions of the basolateral complex of the amygdala (BLA), for instance, selectively disrupt enhancements in cue processing that are normally induced by positive PEs without compromising simple excitatory learning. This result is consistent with electrophysiological evidence showing that BLA neurons track positive PEs. Interestingly, the same neurons also seem to track negative PEs, suggesting the possibility that the BLA might also use these errors to drive enhancements in cue processing. Here, we examined the role of the BLA in the processing (Experiment 1) and utilization (Experiment 2) of negative PEs in increasing cue salience in an unblocking procedure. Using FOS expression as an index of neural activity, Experiment 1 confirmed that BLA neurons track negative PEs with reinforcement downshifts. This tracking was evident both when these errors were generated by decreasing the concentration of a sucrose reinforcer (which encourages the development of conditioned inhibition) and when they were generated by decreasing the number of sucrose reinforcers (which encourages excitatory learning – unblocking – and allows the detection of enhancements in cue processing). Experiment 2 demonstrated that BLA lesions abolished enhancements in cue processing while sparing inhibitory learning. These results suggest a general role of the BLA in utilizing PEs, whatever their sign, for boosting cue processing.     

鞍山市铁东区公共场所卫生基层问题及解决建议

笔者作为基层卫生监督工作人员经过十多年的公共场所卫生监督工作,通过对鞍山市铁东区公共场所卫生监督情况进行分析。发现当前存在许多公共场所卫生监督执法困难和难题,主要表现为卫生监督队伍薄弱,新兴公共场所剧增,公共场所执法依据不确定性（无法可依）等问题。笔者提出相应的解决建议,应转变卫生监督观念,提高监督管理质量。     

Wanted: pediatric nephrologists! — why trainees are not choosing pediatric nephrology

A workforce crisis for many pediatric specialties, particularly nephrology, is due to growing retirement rates, attrition during training, and retention difficulties. To obtain specific information regarding pediatric nephrology trainee shortages, we administered two cross-sectional surveys to non-renal pediatric subspecialty fellows and pediatric nephrology program directors. We characterized the fellows' experiences with nephrology and the program directors' experiences with their fellows as well as their outcomes in the last 10 years. We analyzed responses from 531 non-renal fellows (14.4% response rate). Overall, 317 (60%) fellows rated nephrology as difficult, particularly women (65.4% vs. 49.5%, p?p?=?0.001). More men than women (24% vs. 8%, p?相似文献   

Tyrosine enhances behavioral and mesocorticolimbic dopaminergic responses to aversive conditioning

Tyrosine is a precursor in the biosynthesis of catecholamines and, when administered systemically, has been shown to enhance the in vivo rate of tyrosine hydroxylation in the medial prefrontal cortex. Additionally, exogenous tyrosine has been demonstrated to enhance the pharmacologically-induced increase in dopamine metabolism seen following administration of haloperidol or the anxiogenic B-carboline, FG-7142. In this report, we examine the effect of a physiologically relevant dose of tyrosine (25 mg/kg) on biochemical and behavioral consequences of aversive conditioning. Rats were conditioned to fear a tone by pairing it with footshock, so that when challenged with the tone alone, rats responded with immobility, defecation, and elevated dopamine metabolism in the medial prefrontal cortex and nucleus accumbens. When tyrosine was administered on the test day (tones alone), the rats displayed an even greater elevation of dopamine metabolism in the nucleus accumbens and prolonged immobility to the tone, compared to the saline/conditioned controls. Tyrosine did not alter mobility or dopamine utilization in the nucleus accumbens in nonconditioned controls. However, dopamine metabolism in the medial prefrontal cortex of nonconditioned rats treated with tyrosine was increased to levels similar to those in the conditioned groups. This may be accounted for by handling and by exposure to an unfamiliar environment necessary for nonconditioned controls. We conclude that exogenous tyrosine is able to 1) elevate stress-induced dopamine metabolism in the nucleus accumbens, 2) alter dopamine utilization in the medial prefrontal cortex of handled, nonconditioned controls, and 3) enhance fear-induced immobilization. These data suggest a role for dietary tyrosine in biochemical and behavioral responses to aversive stimuli. © 1996 Wiley-Liss, Inc.     

Theory of rodent navigation based on interacting representations of space

We present a computational theory of navigation in rodents based on interacting representations of place, head direction, and local view. An associated computer model is able to replicate a variety of behavioral and neurophysiological results from the rodent navigation literature. The theory and model generate predictions that are testable with current technologies. © 1996 Wiley-Liss, Inc.     

Neural network modeling of the hippocampal formation spatial signals and their possible role in navigation: A modular approach

Cells throughout the hippocampal formation show striking spatial firing correlates as a rat navigates through space. These cells are thought to play a critical role in orchestrating the navigational abilities of the animals, since damage to the hippocampal formation causes spatial learning deficits. Here, we present a theoretical framework aimed at explaining how the different spatial signals are generated, as well as how they may help guide navigational behavior. Earlier work from our laboratory has presented a simple model for how the location-related signals exhibited by hippocampal place cells could be generated, based on convergent sensory information. Here, the results of this work are combined with two more recent models, to provide a more comprehensive theoretical framework. Specifically, we present 1) A neural network model of head direction cells, based on the idea that the directional signals are generated using a path integration mechanism. Cells which combine directional and angular head velocity information project onto the head direction cells, to “update” the current directional signal. This model reproduces the basic phenomenon of direction-specific firing, as well as the anticipatory nature of this firing, reported for some head direction cells. 2) A network simulation of how the hippocampal spatial signals could be used to orchestrate instrumental learning. Here, place and directional signals converge onto motor cells, each of which are thus driven to fire to specific combinations of location and directional heading. Each active motor cell generates a small leftward or rightward “step” of the simulated animal. When the simulated goal is encountered, recently active synapses are strengthened, so that goal-directed trajectories are “stamped in.” We have found these models useful in helping to clarify our thinking about the proposed theoretical principles, as well as in generating testable predictions. © 1997 Wiley-Liss, Inc.     

Preferences predict who commits crime among young men

Understanding who commits crime and why is a key topic in social science and important for the design of crime prevention policy. In theory, people who commit crime face different social and economic incentives for criminal activity than other people, or they evaluate the costs and benefits of crime differently because they have different preferences. Empirical evidence on the role of preferences is scarce. Theoretically, risk-tolerant, impatient, and self-interested people are more prone to commit crime than risk-averse, patient, and altruistic people. We test these predictions with a unique combination of data where we use incentivized experiments to elicit the preferences of young men and link these experimental data to their criminal records. In addition, our data allow us to control extensively for other characteristics such as cognitive skills, socioeconomic background, and self-control problems. We find that preferences are strongly associated with actual criminal behavior. Impatience and, in particular, risk tolerance are still strong predictors when we include the full battery of controls. Crime propensities are 8 to 10 percentage points higher for the most risk-tolerant individuals compared to the most risk averse. This effect is half the size of the effect of cognitive skills, which is known to be a very strong predictor of criminal behavior. Looking into different types of crime, we find that preferences significantly predict property offenses, while self-control problems significantly predict violent, drug, and sexual offenses.

In choice theory of crime, individuals trade off their benefits from criminal activity against the opportunity costs of legitimate activity and the risks of future costs due to apprehension and punishment (1–3). People can face different trade-offs, for instance, due to differences in how much they can otherwise earn in the labor market, or they can evaluate the trade-offs differently due to differences in preferences. A large empirical literature documents that variation in the trade-off people face predicts who commits crime (3–6). In contrast, little is known about the role of preferences.Key preference parameters are risk tolerance and impatience. Intuitively, crime provides a benefit now but at the risk of a cost in the future which makes crime less attractive for people who dislike risk and care more about future well-being (3). Thus, more risk-tolerant and more impatient people are more prone to commit crime than others (see SI Appendix, SI Text, for a formal derivation in a basic model of criminal behavior). In standard choice theory, people are entirely driven by self-interest, but the theory can be extended to allow for altruistic motives or more sophisticated, other-regarding preferences (7–9). More altruistic people will commit less crime because they care about the costs they inflict on others.In this paper, we ask whether preferences predict who commits crime among young men. We focus on young men (age 18 to 19) who are known to have much higher crime rates than women and older people (3, 10, 11). To answer the question, we leverage a unique combination of data where we use incentivized experiments to elicit the preferences of young men in Denmark and link this experimental data to administrative records with information about all criminal offenses.We examine the association between preferences and crime while also controlling for other differences across people that can explain criminal behavior. The link between experimental data and administrative records enables us to include an extraordinary rich set of relevant control variables. This includes school performance, area of residence, immigrant status, family size, birth order, parental socioeconomic status, criminal records of parents, and family stress as measured by parental divorce or unemployment. Moreover, when we collected the experimental data on preferences, we also asked about self-control which is known to be a strong predictor of crime (12–14). We use this information to control for behavioral factors other than risk, time, and social preferences. We also investigate the relation between preferences and different types of criminal offenses. Arguably, the hypothesis that cost-benefit considerations help explain crime seems more appropriate for property crimes than violent, drug, and sexual offenses where lack of self-control may be a more important driver.This study links experimentally elicited risk, time, and social preferences to actual criminal behavior. We follow a large literature in experimental economics that elicits people’s preferences using incentivized choice experiments, where participants receive payments according to their decisions in the experiment. This literature documents pervasive variation in preferences including that some people are more risk tolerant, impatient, and motivated by self-interest than others (15–17). Studies also show that these parameters are correlated with real-life behavior and outcomes in accordance with theoretical predictions, for example, savings, high school graduation, disciplinary referrals of school children, entrepreneurship, body mass index, and smoking (18–25). The number of participants in our elicitation experiment is large compared to previous studies, and the participants are sampled randomly from the population in contrast to many previous studies which are based on samples of students (26). A large population sample is important for our purpose because crime frequency is low and because students differ significantly from the population at large with respect to their crime propensity.Most closely related to our work is a recent study that finds a significant relationship between patience and criminal offenses (27). The study uses a nonincentivized survey question to measure patience and demonstrates that this predicts crime. Interestingly, the authors find that the predictive power of patience is about one-third of the power of cognitive skills and that patience is most predictive of property crime, which is similar to our findings. Our study differs 1) by providing a more comprehensive and experimentally elicited set of preference measures that include risk preferences and social preferences and 2) by including a self-control measure in the set of predictors. This enables us to 1) show that risk tolerance is the strongest predictor of crime among the preference parameters and 2) document that risk and time preferences significantly predict property crime where self-control is not a significant predictor, whereas in the domain of violent, drug, and sexual offenses, self-control is a key predictor, while risk and time preferences are not significantly predictive.