Memory of the traumatic event as a risk factor for the development of PTSD: lessons from the study of traumatic brain injury

Traumatic memories, and the mechanisms by which they operate, continue to occupy a central role in the scientific investigation of risk factors for the development of posttraumatic stress disorder (PTSD). However, empirically based studies are constrained by practical and ethical considerations and are limited to naturalistic models. Consequently, the paradigms most appropriate for the exploration of the relationship between traumatic memories and PTSD have been identified in conditions involving traumatic events where memories may be compromised. Indeed, traumatic brain injury, a condition that is commonly associated with memory impairment, has often been utilized as a naturally occurring model for the study of traumatic memory and its contribution to the development of PTSD. This article presents a critical review of these research efforts and discusses their theoretical and clinical implications.     

Total sleep deprivation increases the costs of shifting between simple cognitive tasks

In two experiments we studied the effects of one night of total sleep deprivation on task-shift costs. In different conditions shifts were between types of judgment (extradimensional shifts) and between stimulus-response mappings (intradimensional shifts). In addition, with an alternating-runs procedure we used short and long response-to-stimulus intervals and also external precues to vary the opportunities for advance configuration of task sets. Under all conditions sleep deprivation increased shift costs derived from the 20% slowest reaction times, which were insensitive to the opportunities for advance configuration. Shift costs derived from the 20% fastest reaction times were increased only for extradimensional shifts. As indicated by congruency effects, the increase of shift costs after a night without sleep cannot be attributed to increased interference between competing task sets. The findings suggest that total sleep deprivation increases task-set instability and thus lapsing, in particular in conditions with long stimulus-to-response intervals and in shift trials. In addition total sleep deprivation seems to increase the duration of an exogenously controlled process involved in extradimensional shifts.     

Does attention cause illusory line motion?

Illusory line motion (ILM) has been shown to occur when a line is presented with one end next to a previously stimulated location. The line appears to be drawn away from the site of stimulation. It has been suggested that this is because of the allocation of attention to the stimulated site. Using an endogenous attentional manipulation (a central arrow cue) with no differences in the display between the two ends of the line at the time of line presentation or immediately prior, no ILM was detected, though there was a small effect in the opposite direction. Those who have found endogenously induced ILM have used an endogenous cue based on a property of a location marker that indicated the cued location. Changing the method of cuing to one based on a property of a peripheral marker instead of a central arrow produced a small but significant report of ILM. The small magnitude of the effect, participant self-reports, and the absence of the effect in the purely endogenous condition, suggest that this was merely a bias. ILM is not generated by endogenous attention shifts.     

A comparative analysis of serial and free recall

Multitrial free and serial recall tasks differ both in recall instruction and in presentation order across trials. Waugh (1961) compared these paradigms with an intermediate condition: free recall with constant presentation order. She concluded that differences between free and serial recall were due only to recall instructions, and not to presentation order. The present study reevaluated the relation between free and serial recall, using Waugh's three conditions. By examining recall transitions and the organization of information retained across trials, we conclude that presentation order is an important factor, causing participants to exhibit the same temporal associations in serial recall and in free recall with constant presentation order.     

Imitation of a two-action sequence by pigeons

Developmental psychologists have describedimitation as a process that suggests perspective-taking abilities. However, imitative behavior has been found in animals, which are generally not considered capable of taking the perspective of another. Previous studies with birds have demonstrated the imitation of a single response (sometimes referred to asaction-level imitation). In the present experiment, we examined the extent to which pigeons would imitate an unfamiliar sequence of two behaviors (sometimes referred to asprogram-level imitation). Our results indicate that, although there are individual differences, pigeons show a significant tendency to match a demonstrated sequence of behavior involving, first, a response to a treadle (pecking at it or stepping on it) and, second, pushing aside a screen that blocks access to food (a left-vs.-right push).     

Stimulus-response probability and inhibition of return

Inhibition of return (IOR) refers to slowed responding to targets at a location previously occupied by an irrelevant cue. Here we explore the interaction between stimulus-response (S-R) probability and IOR effects using go/no-go (Experiment 1) and two-choice discrimination tasks (Experiment 2). In both experiments, the IOR effect was larger for the likely S-R ensemble than for the unlikely one. In the first experiment, there were more false alarms for uncued targets than for cued targets, and this difference was larger for the unlikely S-R ensemble than for the likely one. In the second experiment, the same pattern was observed for incorrect keypress responses. As with voluntary orienting in response to predictive central cues, the results suggest that IOR affects late stages of processing by altering the criteria to respond to targets presented at the cued (previously attended) location.     

Therapy of treatment resistant depression: focus on the management of TRD with atypical antipsychotics

Treatment-resistant depression (TRD) represents a significant challenge for physicians. About one third of patients with major depressive disorder fail to experience sufficient symptom improvement despite adequate treatment. Despite this high occurrence of TRD there was no general consensus on diagnosis criteria for TRD until 1997 when researchers proposed a model of defining and staging TRD. In 1999, others defined operational criteria for the definition of TRD. Treatment of TRD is commonly separated into pharmacologic and nonpharmacologic methods. This review gives a short overview of these two methods. The nonpharmacologic methods include psychotherapy, electroconvulsive therapy, and vagus nerve stimulation. Pharmacologic methods include switching to another antidepressant monotherapy, and augmentation or combination with two or more antidepressants or other agents. This review especially focuses on the augmentation of the antidepressant therapy with atypical antipsychotics.     

Effects of objective feedback and "single other" or "average other" social comparison feedback on performance judgments and helping behavior

In two studies, participants received positive or negative feedback about their performance on a verbal task and then provided hints to another person on a subsequent, different task. It was expected that participants would give more helpful hints after positive than after negative feedback but that this would be more apparent when the feedback was based on performance comparisons with the "average participant" than on comparisons with another person or an objective standard. This effect was expected to be mediated by judgments of one's performance on the first task. These predictions were supported. Participants seemed aware of the effect of feedback on their hint choices, and their hint choices did not alter their affect levels. Also, participants receiving comparative (single or aggregated target) feedback exhibited changes in self-ascribed importance of the performance domain. Implications for social comparison theory and self-evaluation maintenance theory are discussed.     

Validity of the MMPI-2 and Beck Depression Inventory for making decisions of organ allocation in renal transplantation

Psychosocial factors are presented which affect clinical decision-making regarding the allocation of renal organs. Patients were rated as being either High Risk or Low Risk transplant candidates. High Risk candidates were scored as being significantly different from the Low Risk candidates on many psychosocial variables. Interestingly, significant differences were not found between these two groups on either the MMPI-2 or the Beck Depression Inventory. The validity of using information from these inventories to allocate organs is discussed.