Hippocampal sharp wave bursts coincide with neocortical "up-state" transitions

The sleeping neocortex shows nested oscillatory activity in different frequency ranges, characterized by fluctuations between "up-states" and "down-states." High-density neuronal ensemble recordings in rats now reveal the interaction between synchronized activity in the hippocampus and neocortex: Electroencephalographic sharp waves in the hippocampus were more probable during down-states than during up-states, and tended to coincide with transitions from down-states to up-states. The form of cortical activity fluctuations and their interactions with sharp waves depend on sleep depth: In deeper sleep stages, characterized by strong neocortical oscillation in the delta range or slower (approximately 0.8-4 Hz), sharp-wave-triggered peri-event time histograms (PETH) are consistent with a longer duration for down-states than for up-states. In lighter sleep, the sharp-wave-triggered PETH suggested longer up-states than down-states. These results highlight the interplay in the hippocampal/neocortical loop: Decreased neocortical input during down-states may be a factor in generation of sharp waves. In turn, sharp waves may facilitate down-to-up transitions. This interplay may reflect joint memory trace reactivation in the hippocampus and in the neocortex, possibly contributing to consolidation of long-term memory: Off-line reactivation of recent neural activity patterns in the hippocampus occurs during 50-100-msec electroencephalographic sharp waves, corresponding to pyramidal-cell population bursts. The neocortical up-states starting in correspondence with sharp waves may be influenced by the reactivated information carried by the hippocampal sharp wave.     

Perception of two-body center of mass

Participants estimated the perceptual center of mass between two horizontally oriented black dots varying in size and distance. Experiment 1 showed that estimates, measured as distance from the larger dot's center, decreased with an increase in size ratio between the dots and a decrease in the distance between them, as predicted by the physical center-of-mass equation. The results were replicated and extended in further experiments with different ratios and distances. In all experiments, the true center was consistently overestimated, either because the stimuli were perceived in a low dimensionality or because of a hesitancy to place estimates near the larger dot's edge. In Experiment 4, the center was deliberately placed near this edge for one- and two-dimensional solutions. Participants still overestimated, indicating an "edge effect" as responsible.     

On the transition from childhood amnesia to the recall of personal memories

When adults are asked to report and date personal memories of their pasts, they show childhood amnesia, that is, diminished recall of experiences over the childhood years. This way of demonstrating the phenomenon was supplemented in the present study with a more direct approach: Participants reported events of early childhood that they knew they had experienced (because of family stories, photographs, etc.) but did not actually remember. The resulting cumulative relative frequency distributions produced by the two methods were substantially different, with the median age of remembered events being 6.07 years and of known events, 3.20 years. We suggest that the mean of these two ages, 4.64 years, gives a good indication of when childhood amnesia is eclipsed by personal memories in adults' recall of their personal pasts.     

The over-claiming technique: measuring self-enhancement independent of ability

Over-claiming is a concrete operalization of self-enhancement based on respondents' ratings of their knowledge of various persons, events, products, and so on. Because 20% of the items are nonexistent, responses can be analyzed with signal detection formulas to index both response bias (over-claiming) and accuracy (knowledge). Study 1 demonstrated convergence of over-claiming with alternative measures of self-enhancement but independence from cognitive ability. In Studies 2-3, the validity of the over-claiming index held even when respondents were (a) warned about the foils or (b) asked to fake good. Study 3 also showed the utility of the over-claiming index for diagnosing faking. In Study 4, the over-claiming technique was applied to the debate over the adaptive value of positive illusions.     

Factor structure of the Spielberger Anger Expression scales when used with Australian prisoners

The State-Trait Anger Expression Inventory administered to prison inmates has supported the factor structure of the three anger expression scales although this structure has not been verified with Australian participants. Data collected from 397 Western Australian male prisoners produced a factor structure consistent with the scale structure outlined in the 1991 manual. Scale means and standard deviations were similar to those reported for U.S. and Canadian prisoners. It is therefore appropriate to use the standard scoring procedures with Australian male prisoners.     

Meet The Simpsons: top-down effects in face learning

We examined whether prior knowledge of a person affects the visual processes involved in learning a face. In two experiments, subjects were taught to associate human faces with characters they knew (from the TV show The Simpsons) or characters they did not (novel names). In each experiment, knowledge of the character predicted performance in a recognition memory test, relying only on old/new confidence ratings. In experiment 1, we established the technique and showed that there is a face-learning advantage for known people, even when face items are counterbalanced for familiarity across the experiment. In experiment 2 we replicated the effect in a setting which discouraged subjects from attending more to known than unknown people, and eliminated any visual association between face stimuli and a character from The Simpsons. We conclude that prior knowledge about a person can enhance learning of a new face.     

Aging and repetition effects: separate specific and nonspecific influences

The research reported in this article focuses on processes that contribute to the repetition effect in 2-alternative forced-choice tasks and on how these processes change with age. An analytical approach is presented that allows researchers to discriminate between 2 components of performance. The results of Experiment 1 show that differences in the relative contributions of these 2 processes can produce differences in repetition effects between younger and older adults. Furthermore, as in the negative priming domain, increasing the contribution of 1 of these 2 components can eliminate this age difference. Together, the results argue against the practice of attributing age differences in repetition effects to deficits in any single cognitive process.     

Predicting unit performance by assessing transformational and transactional leadership

How do leadership ratings collected from units operating under stable conditions predict subsequent performance of those units operating under high stress and uncertainty? To examine this question, the authors calculated the predictive relationships for the transformational and transactional leadership of 72 light infantry rifle platoon leaders for ratings of unit potency, cohesion, and performance for U.S. Army platoons participating in combat simulation exercises. Both transformational and transactional contingent reward leadership ratings of platoon leaders and sergeants positively predicted unit performance. The relationship of platoon leadership to performance was partially mediated through the unit's level of potency and cohesion. Implications, limitations, and future directions for leadership research are discussed.     

Converted patients and clinic patients as control cases: a comparison with implications for psychoanalytic training

All twenty-eight respondents to a recent poll of the thirty institutes affiliated with the American Psychoanalytic Association reported that they now accept cases converted from psychotherapy to psychoanalysis as control cases. This study was designed to compare converted cases to clinic cases systematically with respect to patient characteristics, treatment, and the educational experience of the treating candidate. The study followed twenty-four candidates entering analytic training between 1992 and 1995, who treated thirty-four clinic cases and forty-three converted cases between February 1993 and July 2000. Clinic and converted patients were comparable with regard to demographics, prior treatment histories, structural diagnoses, and Axis I diagnoses. In addition, the two groups of cases were indistinguishable with respect to the rate at which candidates received credit toward graduation requirements. Candidates treating converted cases earned approximately dollars 7,600 per patient per year, compared to candidates treating clinic cases, who earned nothing. Eighty-four percent of converted patients diagnosed with a mood disorder by the treating candidate were on medication, in contrast to only 20% of clinic patients with the same diagnosis. Similar differences were seen in the case of anxiety disorders. Given the prevalence of affective and anxiety disorders in control cases and the availability of a variety of medications and psychotherapies with documented efficacy in treating these disorders, candidates should be trained to discuss treatment options with patients who present with Axis I disorders.