Neurocomputational mechanisms of reinforcement-guided learning in humans: A review

Adapting decision making according to dynamic and probabilistic changes in action-reward contingencies is critical for survival in a competitive and resource-limited world. Much research has focused on elucidating the neural systems and computations that underlie how the brain identifies whether the consequences of actions are relatively good or bad. In contrast, less empirical research has focused on the mechanisms by which reinforcements might be used to guide decision making. Here, I review recent studies in which an attempt to bridge this gap has been made by characterizing how humans use reward information to guide and optimize decision making. Regions that have been implicated in reinforcement processing, including the striatum, orbitofrontal cortex, and anterior cingulate, also seem to mediate how reinforcements are used to adjust subsequent decision making. This research provides insights into why the brain devotes resources to evaluating reinforcements and suggests a direction for future research, from studying the mechanisms of reinforcement processing to studying the mechanisms of reinforcement learning.     

《人体器官移植条例》颁布后面临的问题与对策

《人体器官移植条例》规范引导着我国器官移植健康发展,然而,随着《条例》对器官移植供、受者条件的严格限制,尸体供器官数量迅速下降,亲属活体移植逐步占据主导地位,由此引发一系列问题。结合《条例》,就器官来源短缺、保障活体供者安全、亲属活体供者选择和器官移植伦理委员会作用等问题做出较详细的分析,提出解决方法和对策。     

The role of corticotrophin-releasing hormone receptors in the calcitonin gene-related peptide-induced suppression of pulsatile luteinising hormone secretion in the female rat

Corticotrophin-releasing hormone (CRH) plays a pivotal role in the suppression of the gonadotrophin-releasing hormone (GRH) pulse generator in response to stress and intracerebroventricular (i.c.v.) administration of calcitonin gene-related peptide (CGRP). We have previously shown both CRH receptor subtypes, CRH-R1 and CRH-R2, are involved in the stress-induced suppression of LH pulses. The aims of the present study were to examine the role of CRH-R1 and CRH-R2 in CGRP-induced suppression of LH pulses, and to investigate the effects of CGRP on CRH expression in the paraventricular nucleus (PVN) and central nucleus of the amygdala (CeA), which have prominent CRH neurone populations that receive dense CGRP innervations. The suppression of LH pulses by CGRP (1.5 microg i.c.v.) was completely prevented by intravenous administration of the CRH-R1 antagonist SSR125543Q (7.5 mg/rat i.v., 30 min before CGRP), but was not affected by the CRH-R2 antagonist, astressin(2)-B (100 microg i.c.v., 10 min before CGRP). CGRP increased the CRH mRNA expression in PVN and CeA. These results provide evidence of a role for CRH-R1 in mediating the suppressive effects of CGRP on pulsatile LH secretion in the female rat, and additionally raise the possibility of an involvement of PVN and CeA CRH neuronal populations in this suppression.     

A memory-based, Simon-like, spatial congruence effect: Evidence for persisting spatial codes

The Simon effect refers to the finding that in a task where stimulus location is irrelevant, reaction time is faster when stimulus and response locations are congruent than when they are not. Dominant theories of the Simon effect have generally attributed this spatial congruence effect to a spatial code automatically generated upon stimulus presentation. A common assumption of these theories is that this spatial code decays in less than a few hundred milliseconds following stimulus onset. We report two working-memory experiments suggesting a reexamination of this assumption—a Simon-like spatial congruence effect persisted over a delay of as long as 2400 ms. We propose that, in addition to generating short-lived perceptual codes, spatial information may be coded in working memory as part of the context associated with stimulus events. When reactivated by cues from the original event, such information may influence response selection and produce spatial congruence effects (in this case, positive when participants made a “yes” response and negative when they made a “no” response).     

Useful predictors of counseling effectiveness

A summary is given of research on characteristics of effective counselors in terms of indicators that show promise as predictors of counselor effectiveness as well as indicators that appear to possess little or no such promise. Recommendations are made for the use of these findings in research and practice.     

SELF-ESTEEM AND JOB PERFORMANCE: THE MODERATING ROLE OF SELF-ESTEEM CONTINGENCIES

Although theoretical perspectives suggest self-esteem level (i.e., high/low) should have main and moderating effects on job performance, empirical and narrative reviews of the literature suggest such effects are either nonexistent or highly variable. To account for these mixed findings, we hypothesized that self-esteem level should only have main and moderating effects on job performance when one's self-esteem is not contingent upon workplace performance. Using multisource ratings across 2 samples of working adults, we found that the importance of performance to self-esteem (IPSE) moderated the effect of self-esteem level on job performance and moderated the buffering interaction between self-esteem level and role conflict in the prediction of job performance. Our results thus support IPSE as an important moderator of both main and moderating effects of self-esteem level.     

Risk perceptions: assessment and relationship to influenza vaccination.

OBJECTIVE: Accurate measurement of beliefs about risk probability is essential to determine what role these beliefs have in health behavior. This study investigated the ability of several types of risk perception measures and of other constructs from health behavior theories to predict influenza vaccination. DESIGN: Prospective study in which students, faculty, and staff at 3 universities (N = 428) were interviewed in the fall, before influenza vaccine was available, and again early in the next calendar year. MAIN OUTCOME MEASURE: Self-reported influenza vaccination. RESULTS: Two interview questions that asked about feeling at risk and feeling vulnerable predicted subsequent behavior better (r = .44, p = .001) than 2 questions that asked for agreement or disagreement with statements about risk probability (r = .25, p = .001) or 4 questions that asked respondents to estimate the magnitude of the risk probability (r = .30, p = .001). Of the 4 perceived risk magnitude scales, a 7-point verbal scale was the best predictor of behavior. Anticipated regret was the strongest predictor of vaccination (r = .45, p = .001) of all constructs studied, including risk perceptions, worry, and perceived vaccine effectiveness. CONCLUSION: Risk perceptions predicted subsequent vaccination. However, perceived risk phrased in terms of feelings rather than as a purely cognitive probability judgment predicted better. Because neither feeling at risk nor anticipated regret is represented in the most commonly used theories of health behavior, the data suggest that these theories are missing important constructs.