Depression and preference for self-focusing stimuli after success and failure

Depressed individuals, who tend to have large perceived-self/ideal-self discrepancies, have been shown to be particularly high in private self-consciousness. On the bases of this finding and of several converging theoretical perspectives, we hypothesized that depressives, unlike nondepressives, do not find self-focus more aversive after failure than after success, and thus either (a) show no differential preference for self-focusing stimuli after success versus after failure (weak hypothesis), or (b) prefer self-focusing stimuli after failure over self-focusing stimuli after success (strong hypothesis). Depressed and nondepressed college students succeeded or failed on a supposed test of verbal intelligence, and then worked on two sets of puzzles, one in the presence and one in the absence of a self-focusing stimulus (mirror). Whereas nondepressed subjects liked the mirror-associated puzzle more after success than after failure, depressed subjects did not; depressed subjects tended to like the mirror-associated puzzle more after failure than after success. Nondepressed subjects also exhibited a self-serving pattern of attributions, viewing the test as less valid and luck as more responsible for their performance after failure than after success; depressed subjects showed no such differences. In consistency with their failure to use defensive strategies, depressed subjects showed a decrease in self-esteem after failure; nondepressed subjects showed no such change.     

The role of long-term-memory and short-term-memory links in the Simon effect

In Experiment 1, children performed a Simon task after a spatially compatible or incompatible task. Results showed a Simon effect after the spatially compatible task and a reversed Simon effect after the spatially incompatible task. In Experiments 2-5, an identical procedure was adopted with adult participants, who performed the Simon task immediately after, a day after, or a week after the spatial compatibility task. Experiment 6 established a baseline for the Simon effect. Results showed a Simon effect after the spatially compatible task and no Simon effect or a reversed Simon effect after the spatially incompatible task. A modified version of the computational model of M. Zorzi and C. Umiltà (1995) was used to compare possible accounts of the findings. The best account exploits 2 types of short-term-memory links between stimulus and response and their interaction with long-term-memory links.     

The response-reinforcement dependency in fixed-interval schedules of reinforcement

Pigeons were exposed to four different schedules of food reinforcement that arranged a fixed minimum time interval between reinforcements (60 sec or 300 sec). The first was a standard fixed-interval schedule. The second was a schedule in which food was presented automatically at the end of the fixed time interval as long as a response had occurred earlier. The third and fourth schedules were identical to the first two except that the first response after reinforcement changed the color on the key. When the schedule required a peck after the interval elapsed, the response pattern consisted of a pause after reinforcement followed by responding at a high rate until reinforcement. When a response was not required after the termination of the interval, the pattern consisted of a pause after reinforcement, followed by responses and then by a subsequent pause until reinforcement. Having the first response after reinforcement change the color on the key had little effect on performance. Post-reinforcement pause duration varied with the minimum interreinforcement interval but was unaffected by whether or not a response was required after the interval elapsed.     

Characteristics and reversibility of dementia in Normal Pressure Hydrocephalus

Studies of the cognitive outcome after shunt insertion for treatment of Normal Pressure Hydrocephalus have reported widely mixed results. We prospectively studied performance of 60 patients with Normal Pressure Hydrocephalus on a comprehensive battery of neuropsychological tests before and after shunt surgery to determine which cognitive functions improve with shunt insertion. We also administered a subset of cognitive tests before and after temporary controlled drainage of cerebrospinal fluid to determine if change on this brief subset of tests after drainage could predict which patients would show cognitive improvement three to six months after shunt insertion. There was a significant improvement in learning, retention, and delayed recall of verbal memory three to six months after surgery (using paired t-tests). The majority (74%) of patients showed significant improvement (by at least one standard deviation) on at least one of the memory tests. Absence of improvement on verbal memory after temporary drainage of cerebrospinal fluid had a high negative predictive value for improvement on memory tests at 3-6 months after surgery (96%; p=0.0005). Also, the magnitude of improvement from Baseline to Post-Drainage on few specific tests of learning and recall significantly predicted the magnitude of improvement after shunt surgery on the same tests (r2=0.32-0.58; p=0.04-0.001). Results indicate that testing before and after temporary drainage may be useful in predicting which patients are less likely to improve in memory with shunting.     

The failure of stimulus control after presence-absence discrimination of click-rate

Pigeons were trained to discriminate a slow click-rate from its absence, or to discriminate it from a faster click-rate. Subsequent click-rate generalization tests produced the usual steepened gradients after the intradimensional discrimination but produced flat gradients after presence/absence discrimination. The occurrence of stimulus control only after intradimensional discrimination, combined with previous results showing stimulus control sometimes after nondifferential reinforcement and sometimes after presence/absence discrimination, argues for a reformulation of the problem of stimulus control. A theoretical framework, relying upon blocking effects inherent in the different discrimination procedures, was presented to account for the diversity of results.     

Factors affecting baseline nociceptive sensitivity

The present study examined factors with the potential to affect sensitivity of the tail flick measure of thermal nociception in rats. The length of the habituation period before testing began, the apparatus ramp speed, and the light:dark cycle were manipulated in a within-subjects design to determine which factors minimize the variability between baseline trials. Factors had little effect on mean baseline latencies, but standard deviations were affected. Lower variability occurred after 0- and 15-min habituation periods than after 60-min periods, after a constant light cycle than after a light:dark cycle, and after a higher temperature thermal apparatus than after a lower temperature. Although statistically significant, these effects were modest in size. These results may be of some use to those comparing studies that used very different parameters and to those designing studies and trying to optimize conditions.     

The benzodiazepine midazolam does not impair Pavlovian fear conditioning but regulates when and where fear is expressed.

Rats were injected with a benzodiazepine (midazolam) and shocked after presentation of an auditory conditioned stimulus (CS). They were then tested for fear reactions (freezing) to the CS in either the original context or a 2nd context after either a short (1-day) or long (21-day) retention interval. Rats tested in the original context froze less after 1 day than rats tested after that interval in the 2nd context or rats tested after 21 days. Moreover, rats tested after the long interval in the original context froze less than rats tested after that interval in the 2nd context. Therefore, midazolam does not impair the acquisition of conditioned fear but regulates when and where that fear is expressed. These effects of midazolam were interpreted as a contextually controlled deficit in the expression of conditioned fear that is similar to that associated with latent inhibition and extinction (M. E. Bouton, 1993).     

社会支持、主动反刍与创伤后应激障碍的关系:来自地震后青少年的追踪研究

以追踪研究的方式,在汶川地震后3.5年、4.5年和5.5年三个时间点,采用社会支持问卷、反刍问卷和创伤后应激障碍量表对汶川地震后245名中学生进行调查。通过建立交叉滞后模型,考察社会支持、主动反刍与创伤后应激障碍(PTSD)的相互作用关系。结果发现,震后3.5年至5.5年间,社会支持与主动反刍之间的跨时间点预测作用不显著,PTSD对社会支持的跨时间点预测作用不显著,但对主动反刍具有显著的跨时间点正向预测作用。震后3.5年至4.5年间,社会支持对PTSD的跨时间点负向预测作用、主动反刍对PTSD的跨时间点正向预测作用均显著,但是这些作用在震后4.5年至5.5年间变得不再显著。     

Temporal Distribution of Attention During a Throwing Motion

A reaction-time measure of attention was employed during five segments of a simultaneous dart throw: premovement decision, immediately after recoil was begun, maximum recoil, immediately after forward movement was begun, and after release of the dart. Reaction time was significantly longer when the stimulus was presented during the first or second segment than during later segments. Reaction time during premovement was not consistently greater than that immediately after movement was begun, indicating that information is being sampled at a high rate after movement commences. It appears that monitoring of proprioceptive feedback after movement has begun, and initiation of corrective submovements, is necessary for skillful performance of dart throwing.     

Brief wakeful resting boosts new memories over the long term

A brief wakeful rest after new verbal learning enhances memory for several minutes. In the research reported here, we explored the possibility of extending this rest-induced memory enhancement over much longer periods. Participants were presented with two stories; one story was followed by a 10-min period of wakeful resting, and the other was followed by a 10-min period during which participants played a spot-the-difference game. In Experiment 1, wakeful resting led to significant enhancement of memory after a 15- to 30-min period and also after 7 days. In Experiment 2, this striking enhancement of memory 7 days after learning was demonstrated even when no retrievals were imposed in the interim. The degree to which people can remember prose after 7 days is significantly affected by the cognitive activity that they engage in shortly after new learning takes place. We propose that wakeful resting after new learning allows new memory traces to be consolidated better and hence to be retained for much longer.     

Timing matters: Temporal dynamics of stress effects on memory retrieval

Stress may impair memory retrieval. This retrieval impairment has been attributed to the action of the stress hormone cortisol, which is released with a delay of several minutes after a stressful encounter. Hence, most studies tested memory retrieval 20–30 min after stress, when the stress-induced cortisol increase peaks. In the present experiment, we investigated whether retrieval impairments can also be found at later intervals after stress. To this end, participants learned a list of words on day 1. Twenty-four hours later, they were first exposed to a stressor or a nonstressful control manipulation and completed a recognition test for the words either immediately thereafter, 25 min later, or 90 min later. Our findings showed that stress did not impair memory retrieval when memory was tested immediately after the stressor, before cortisol levels were elevated. However, retrieval performance was impaired 25 min after stress, when cortisol levels peaked, as well as 90 min after the stressor, when cortisol levels had already returned to baseline. The retrieval impairment 90 min after stress appeared to be even stronger than the one after 25 min. These findings suggest that the detrimental effects of stress on retrieval performance may last longer than is usually assumed.     

Polydipsia induced in rats by second-order schedules of reinforcement.

Three rats were exposed to a second-order schedule in which fixed-interval components ended either with food or with a brief stimulus that was never paired with food. Food and the brief stimulus occurred in a random sequence (variable-ratio 2 overall schedule). Another three rats were exposed to a similar second-order schedule, the only difference being that the food or the stimulus was presented independently of operant behavior (fixed-time components). The three rats exposed to the fixed-interval components licked at a water spout after each food presentation. These rats also licked in the intervals after the brief stimulus. Although the discriminative properties of food and of the brief stimulus were identical in relation to subsequent reinforcement, licking after the stimulus was less than after food. The three rats exposed to the second-order schedules with fixed-time components also licked at the water spout after food, but these rats did not lick consistently after brief stimulus presentations.     

The retrieval of self-defining memories is associated with the activation of specific working selves

This article presents two studies that investigated the impact of the retrieval of self-defining memories on individuals' sense of self. Participants recalled positive and/or negative self-defining memories, rated memory characteristics and completed measures focusing on different self-aspects. Study 1 found that participants reported higher state self-esteem after recalling a positive memory than after recalling a negative one. They also reported lower negative self-consistency and higher state self-concept clarity and positive self-consistency, but this result became non-significant after controlling for state self-esteem. Study 2 found that participants reported higher state self-esteem, a marginally higher proportion of recreation/exploration, goals and a marginally lower proportion of achievement goals after recalling a positive memory than after recalling a negative one. They also reported a higher proportion of self-cognitions referring to emotional states after recalling memories from which they had not abstracted meaning than after recalling memories from which they had done this. These findings suggest that the retrieval of vivid, emotional and highly self-relevant memories may be accompanied by the activation of specific self-representations or working selves. They also suggest that the experience of memory-related intrusive images may temporarily influence individuals' sense of self. The implications of these findings for clinical practice are discussed.     

Self-awakening, sleep inertia, and P3 amplitude in elderly people

It is well known that sleepiness is sometimes experienced in the afternoon. A short afternoon nap is thought to be effective in reducing sleepiness. However, sleep inertia occurs even after a short nap, and this could be a major risk factor for injuries from falling by the elderly. In the present study, the effect of self-awakening on sleep inertia after a 20-min. nap was examined. Nine participants (M=74.1 yr., SD=5.0 yr.) took part in the three experimental conditions: the self-awakened nap, the forced-awakened nap, and the control (no-nap) conditon. Analysis showed sleepiness and performance after the nap significantly improved compared with the control condition. P3 amplitude tended to be larger after self-awakening than after forced-awakening. The present study indicates a 20-min. nap reduces afternoon sleepiness, and the application of self-awakening may contribute to higher arousal after a nap taken by this elderly group.     

Selective mechanisms in visual perception

The notion of perceptual tuning is investigated by presenting alternatives either before, after, or both before and after a tachistoscopic stimulus. Study 1 (N = 12) showed that identification accuracy is best with alternatives both before and after the stimulus, poorest with alternatives after the stimulus, and intermediate with alternatives only before the stimulus. Study 2 (N = 3) indicated that performance with alternatives both before and after the stimulus varies according to where S is permitted to fixate prior to each exposure. The possibility of a central tuning mechanism was not strongly supported.     

Forgetting of recently acquired or recently reactivated memories

Four experiments compared the rates of forgetting following acquisition of a conditioned aversion and following a reactivation treatment given long after conditioning had been completed. The “reactivation treatment” consisted of a single presentation of the unconditioned stimulus, a procedure known to reinstate, following substantial forgetting, the behavior seen immediately after conditioning. It was first determined that the decrement in performance 1, 3, or 7 days later tended to be more rapid just after original conditioning than following a reactivation treatment given 27 days after conditioning. Subsequent experiments confirmed that the forgetting seen 3 or 7 days after original conditioning was in fact greater than forgetting 3 or 7 days after the reactivation treatment that had followed conditioning by 27 days; also, tests permitted rejection of the hypothesis that this effect could be attributed to nonassociative (systemic) consequences of the conditioning situation. Finally, tests indicated that retention 24 hr after a reactivation treatment was significantly better if the reactivation treatment followed conditioning by 27 days than if it were given just 3 min or 24 hr after conditioning. The central observation emerging from this study, that forgetting is more rapid following original learning than following a temporally remote reactivation treatment, was discussed in terms of potential interactions between the age (or accessibility) of a memory and processes that might be instigated by a reactivation treatment.     

Drug states as discriminative stimuli in a flavor-aversion learning experiment

Injection of poison into rats after they drank in the presence of stimulus compounds of a drug state and a flavor resulted in little stimulus control by the drug state. In Experiment 1, half of the rats were poisoned after drinking salt water while stimulated with amphetamine and after drinking sugar water while sedated with pentobarbital, but they were not poisoned after salt-pentobarbital or sugar-amphetamine combinations. The other half were subjected to counterbalanced procedures. In abstract language, poisoning occurred after AX and BY stimulus combinations but did not occur after AY and BX combinations. In Experiment 2A, rats were poisoned only after consuming a particular flavored solution (salt or vinegar) in a particular state (pentobarbital or undrugged); that is, if AX was poisoned, BX, BY, and AY were experienced without poisoning. There was complete counterbalancing of flavors and drug states. Experiment 2B was similar except that amphetamine was used instead of pentobarbital. In both experiments, there was some discrimination learning based on the drug state, gut it was extremely weak.     

Potentiation by a novel flavour of conditioned place aversions based on both toxicosis and shock

Three experiments examined how a flavour modified the development of aversions to the place in which it was presented and paired with a reinforcer. Experiment 1 confirmed the cue-to-consequence effect: rats made sick after exposure to a flavour in a novel place (Skinner boxes) displayed stronger aversions than shocked animals when they were presented with the flavour in a second, familiar place; rats shocked after exposure to water acquired stronger place aversions than animals made sick. Experiment 2 confirmed the potentiation effect: rats made sick after exposure to the flavour developed stronger place aversions than those made sick after ingestion of water. This experiment also revealed that rats shocked after exposure to the flavour likewise acquired stronger place aversions than the animals shocked after ingestion of water. Experiment 3 replicated this flavour potentiation of place aversions based on shock. The results are not consistent with Garcia, Lasiter, Bermudez-Rottoni, & Deems' (1985) account of how a flavour interacts with an aversive reinforcer to modify what is learned about its associates in a compound.     

The effect of rehearsal delay on long-term imitation of filmed aggression

An experiment is described which investigates the effect of rehearsal delay on long-term imitation of a film model. The hypothesis tested was that a delay in the opportunity to imitate a film model would result in a reduction of imitation, ‘flitting’ and range of activities during play in the stimulus situation. One group of children played immediately after exposure to the film, a second after a delay of one day, a third after one week. All groups returned after an interval of seven days, and again after 4–5 months. The hypotheses were not accepted; the film influenced behaviour whatever the delay, but it was noted that the general effect of the films on activity level was less marked during the second session in the experimental situation, and increased after a few months' interval. The long-term effect of the film model was noted, and it was observed that at this time retention of the film model's behaviour was not related to imitative behaviour.     

Late expression of brain-derived neurotrophic factor in the amygdala is required for persistence of fear memory

In many instances, increase in neuronal activity can induce biphasic secretion of a modulator. The initial release of the modulator triggers the induction of synaptic plasticity, whereas the second-phase release reinforces the efficacy of synaptic transmission and growth of dendrites and axons. In this study, we showed that fear conditioning not only induced the first but also a second peak of brain-derived neurotrophic factor (BDNF) expression. Fluorescent immunohistostaining confirmed that BDNF expression increased at 1 and 12 h after conditioning and returned to baseline at 30 h after conditioning. Mature BDNF expression increased in a similar manner. TrkB-IgG or K252a infusion before training impaired fear memory on days 1 and 7 after training. In contrast, TrkB-IgG or K252a infusion 9 h after fear conditioning did not affect memory retention on day 1 after training but impaired fear memory on day 7 after training. Fear conditioning significantly enhanced Zif268 expression in the amygdala at 12 h after training; this enhanced expression was completely inhibited by TrkB-IgG infusion 9 h after training. The level of growth-associated protein 43 (GAP-43), a marker of newly formed synapses, in the amygdala increased 7 days after fear conditioning. Moreover, conditioned rats had higher AMPA/NMDA ratio than unpaired rats. These results suggest that consolidated memory could be continuously modulated by previous molecular changes produced during memory acquisition.