No Time of Day Modulation or Time Stamp on Multiple Memory Tasks in Rats

Various demonstrations of “time stamp” effects in the animal learning literature have reinforced the idea that circadian information is encoded as part of a combined internal/external representation of context and that this contextual information is utilized for complex retrieval processes supporting memory. The goal of the present series of experiments is to assess this idea by manipulating training/testing circadian times on a battery of learning and memory tasks commonly used in the rodent. The data obtained from five experiments using four different learning and memory paradigms provide no evidence for “time stamp” effects on place memory, context memory (aversive or appetitive), or S-R habit learning.     

Two types of pigeon key pecking: suppression of long- but not short-duration key pecks by duration-dependent shock

The key pecking of eight pigeons was maintained on a variable-interval 1-minute schedule of food reinforcement. Sometimes, all responses between 35 and 50 milliseconds in duration produced a shock; sometimes, all responses between 10 and 25 milliseconds produced a shock; sometimes, shocks were produced by pecks without regard to duration (nondifferential punishment), and sometimes shocks were delivered independently of responding. Punishment of 35- to 50-millisecond responses selectively suppressed those responses, while punishment of 10- to 25-millisecond responses and nondifferential punishment suppressed responding overall but did not suppress responses of particular duration. Punishment of 35- to 50-millisecond responses suppressed key pecking slightly less than did nondifferential punishment. Punishment of 10- to 25-millisecond responses and response-independent shock produced roughly equal amounts of suppression, substantially less than the other punishment procedures. The data support the view that there are at least two kinds of key peck, identifiable on the basis of duration, one of which (short duration) is insensitive to its consequences.     

Effect of anxiety on behavioural pattern separation in humans

Behavioural pattern separation (BPS), the ability to distinguish among similar stimuli based on subtle physical differences, has been used to study the mechanism underlying stimulus generalisation. Fear overgeneralisation is often observed in individuals with posttraumatic stress disorder and other anxiety disorders. However, the relationship between anxiety and BPS remains unclear. The purpose of this study was to determine the effect of anxiety (threat of shock) on BPS, which was assessed across separate encoding and retrieval sessions. Images were encoded/retrieved during blocks of threat or safety in a 2?×?2 factorial design. During retrieval, participants indicated whether images were new, old, or altered. Better accuracy was observed for altered images encoded during periods of threat compared to safety, but only if those images were also retrieved during periods of safety. These results suggest that overgeneralisation in anxiety may be due to altered pattern separation.     

自发性气胸致失血性休克诊疗策略

分析自发性气胸（spontaneous pneumothorax,SP）出现失血性休克时的临床特点、探讨诊疗策略。分析331例SP并失血性休克的病例资料。结果采用手术治疗者效果最佳。SP致失血性休克者多见于青年男性,多为胸膜顶粘连带出血,急诊微创手术是治疗发展方向。     

感染性休克患者术前应用盐酸戊乙奎醚的临床疗效

观察盐酸戊乙奎醚在感染性休克患者中作为术前药应用的临床疗效。感染性休克手术患者40例,随机分为2组：实验组术前30min肌注盐酸戊乙奎醚lmg,对照组肌注东莨菪碱0．3mg。于各时间点检测血乳酸值、血气（PaO2、PaCO2）及胃黏膜二氧化碳分压（PgCO2）。结果示实验组血乳酸下降、PaO2上升,PgCO2一PaCO...     

Stimuli inevitably generated by behavior that avoids electric shock are inherently reinforcing.

A molecular analysis based on the termination of stimuli that are positively correlated with shock and the production of stimuli that are negatively correlated with shock provides a parsimonious count for both traditional discrete-trial avoidance behavior and the data derived from more recent free-operant procedures. The necessary stimuli are provided by the intrinsic feedback generated by the subject's behavior, in addition to those presented by the experimenter. Moreover, all data compatible with the molar principle of shock-frequency reduction as reinforcement are also compatible with a delay-of-shock gradient, but some data compatible with the delay gradient are not compatible with frequency reduction. The delay gradient corresponds to functions relating magnitude of behavioral effect to the time between conditional and unconditional stimuli, the time between conditioned and primary reinforcers, and the time between responses and positive reinforcers.     

MANIPULATION OF POTENTIAL PUNISHMENT PARAMETERS IN THE TREATMENT OF SELF-INJURY1

The self-injurious behavior (SIB) of a blind, profoundly retarded male was observed within a field setting as multiple forms of punishment were applied. The effects of hair-tug punishment were first systematically examined, then hair-tug and electric shock punishment were administered in varing ratios (of punishment deliveries per SIB response) supplemented by continuous restraint contingencies and made contingent on recurrent antecedents of SIB cycles. Treatments were applied over six months of consecutive daily sessions ranging from 30 min to 8 hr duration. Posttreatment followup observations were taken 12, 24, and 34 months after treatment. Partial suppression was produced as a direct function of hair-tug punishment in the initial phase. A generally progressive decrement was produced on already lowered SIB rates with the succeeding components of the treatment package. Extended periods of total SIB suppression occurred as punishment was rendered contingent on antecedent components of each SIB response cycle. Followup observations of nearly 3 yr duration indicated total suppression generalized over all settings in which the subject functioned. The findings were related to the contrasting limits prevailing in most reports of punishment-based SIB suppression.     

Effects on responding of mixed and multiple schedules of signalled and unsignalled response-dependent electric-shock delivery

Responding in two rats was maintained under mixed and multiple variable-interval 35-sec variable-interval 35-sec food delivery schedules. Similar rates and patterns of responding occurred in each component of the two schedules. Mixed and multiple variable-interval 65-sec variable-interval 65-sec schedules of response-dependent shock delivery were super-imposed on the mixed and multiple baseline food schedules, respectively. In one component, a 5-sec stimulus was presented on the average of once every 65 sec. Offset of the stimulus arranged that the next response would produce shock. In the other component, no stimulus was presented during the 5-sec period. The mixed schedule of signalled and unsignalled dependent shock delivery yielded similar degrees of response suppression in each component, but the multiple schedule of shock delivery revealed differential degrees of response suppression. Considerably more suppression occurred in the component not associated with the preshock stimulus, thus implicating the discriminative functions of the correlated stimulus.     

Withdrawal,matching, withdrawal-matching,and variable-matching strategies in reducing attack-instigated aggression

Several studies have investigated strategies that a participant in dyadic aggression may use to reduce the aggression of the other participant. In one set of these studies the subject is instigated to aggression by an opponent who sets maximum shocks for the subject to receive during the first block of six trials. Following attack-instigation, opponents shift to withdrawal and matching strategies for 18 trials. The withdrawal strategy is an abrupt shift to the lowest levels of shock possible. The matching strategy is the exact matching by an opponent of the shock set by the subject on the previous trial. With these procedures the withdrawal strategy has been the most effective method to reduce aggression. These results led to the suggestion that the effectiveness of the withdrawal strategy may be due to immediate, unambiguous communication by the opponent of his willingness to reduce attack. This hypothesis was tested in the present study by creating a matching condition modified to include immediate, unambiguous communication of willingness to reduce attack. In this withdrawal-matching condition the opponent followed attack with two trials of the lowest levels of shock before shifting to a matching strategy. Although the withdrawal-matching strategy did not lead to shock settings that were significantly lower than the matching strategy, there was evidence that subjects interacting with withdrawal-matching opponents did reduce their shock settings from block 1 to block 4 more rapidly than subjects interacting with matching opponents. A variable matching strategy was also used to provide a more realistic analogy of matching in the mundane world. While subjects with variable-matching opponents also did not set shock levels during blocks 2, 3, and 4 that were significantly lower than the matching strategy, there was evidence that subjects in this condition reduced their shock levels more rapidly than subjects with matching opponents. Although the effects were not as strong as expected, the results do provide some support for the interpretation that the effectiveness of the withdrawal strategy may be due to unambiguous communication of willingness by the opponent to reduce his or her aggression. The effectiveness of the variable-matching strategy was attributed to interrupting the tendency of the subject and his or her opponent to match each other's responses. Consistent with earlier attack-instigated aggression studies, the withdrawal strategy in the present study led to a rapid reduction in aggression.     

怎样看待和认识休克

哲学素质在现代医学实践中具有重要意义,它不仅是医务工作者的思维武器,更是了解医学前沿和解决医学难题的钥匙。本文就以休克这一临床上常见的危急重症为例,探讨休克发生发展过程中的哲学因素,旨在阐明自觉运用马克思主义哲学的思辨观来指导休克的诊疗过程实属必要,对医生及患者都大有益处。