An exploration of leadership in a medical mutual help organization

Studied 45 current leaders of local chapters of a medical mutual help organization. Cluster analysis of variables depicting routes to leadership produced six clusters: Health Professionals with a Mission, Connected Health Professionals, Career Leaders, Grass-roots Founders, Connected Grass-roots Leaders, and Obligated Veterans. These clusters differed on criterion measures of burnout, hardiness, and perceived obligation to continue as a leader, e.g., Connected Health Professionals and Career Leaders were less burned out, more hardy, and perceived less of an obligation to continue in the leadership role than Health Professionals with a Mission. In terms of leadership activities, Help Provision and Advocacy constituted less than one fifth of all activities but were rated as most rewarding. In contrast, the activities that made up the bulk of leaders' work--building membership, system maintenance, and organizational growth--were not rated as particularly rewarding. Results are discussed in the context of research directions and practice.     

Cognitive performances and locomotor activity following dentate granule cell damage in rats: role of lesion extent and type of memory tested

Intradentate injection of colchicine is one of the techniques used to destroy granule cells. This study compared the behavioral effects of various amounts of colchicine (1.0, 3.0, and 6.0 microg; Col 1, Col 3, and Col 6, respectively) injected into the dentate gyrus of adult Long-Evans male rats. Starting 10 days after lesion surgery, behavioral testing assessed home-cage and open-field locomotion, alternation in a T-maze, water-maze, and radial-maze learning according to protocols placing emphasis on reference, and working memory. All of these tasks are sensitive to hippocampal disruption. Histological verifications showed that the extent of the lesions depends on the dose of colchicine (index of dentate gyrus shrinkage: -33% in Col 1, -54% in Col 3, and -67% in Col 6 rats). Colchicine dose-dependently increased nocturnal home cage activity (an effect found 10 days but not 5 months after surgery), but had no significant effect on open-field locomotion or T-maze alternation. A dose-dependent reference memory impairment was found during the acquisition of spatial navigation in the water maze; Col 3 and Col 6 rats were more impaired than Col 1 rats. During the probe trial (platform removed), control rats spent a longer distance swimming over the platform area than all rats with colchicine lesions. In the working memory version of the test, all rats with colchicine lesions showed significant deficits. The deficits were larger in Col 3 and Col 6 rats compared to Col 1 rats. The lesions had no effect on swimming speed. In the radial-maze test, there was also a dose-dependent working memory impairment. However, reference memory was disrupted in a manner that did not differ among the three groups of lesioned rats. Our data are in line with the view that the dentate gyrus plays an important role in the acquisition of new information and is an integral neural substrate for spatial reference and spatial working memory. They also suggest that damage to granule cells might have more pronounced effects on reference than on working memory in the radial maze. Finally, they demonstrate that part of the variability in the conclusions from previous experiments concerning the role of granule cells in cognitive processes, particularly in spatial learning and memory, may be due to the type of tests used and/or the extent of the damage produced.     

Social demand characteristics in children's and adults' eyewitness memory and suggestibility: the effect of different interviewers on free recall and recognition

Shortly after viewing a video of a theft, 5‐ and 7‐year‐old children and adults were interviewed with free recall and either misleading or unbiased‐leading questions. After a 2‐day delay, participants were interviewed with free recall and recognition questions administered by either the same or a different interviewer. Results from day 1 replicate previous findings with levels of recall and resistance to suggestibility increasing with age. Counter to predictions, correct recognition performance on day 2 was greater for some participants interviewed by the same as opposed to a different interviewer, and incorrect recognition was greater for all groups of participants for those interviewed by a different as opposed to the same interviewer. Results are discussed in terms of the role of context dependence on memory performance. Copyright © 2000 John Wiley & Sons, Ltd.     

Processing modifier-head agreement in reading: Evidence for a delayed effect of agreement

The present study examined whether type of inflectional case (semantic or grammatical) and phonological and morphological transparency affect the processing of Finnish modifier-head agreement in reading. Readers' eye movement patterns were registered. In Experiment 1, an agreeing modifier condition (agreement was transparent) was compared with a no-modifier condition, and in Experiment 2, similar constructions with opaque agreement were used. In both experiments, agreement was found to affect the processing of the target noun with some delay. In Experiment 3, unmarked and case-marked modifiers were used. The results again demonstrated a delayed agreement effect, ruling out the possibility that the agreement effects observed in Experiments 1 and 2 reflect a mere modifier-presence effect. We concluded that agreement exerts its effect at the level of syntactic integration but not at the level of lexical access.     

Environmental cue saliency influences the vividness of a remote spatial memory in rats

The Morris water maze is frequently used to evaluate the acquisition and retrieval of spatial memories. Few experiments, however, have investigated the effects of environmental cue saliency on the strength or persistence of such memories after a short vs. long post-acquisition interval. Using a Morris water maze, we therefore tested in rats the effect of the saliency of distal cues on the vividness of a recent (5 days) vs. remote (25 days) memory. Rats trained in a cue-enriched vs. a cue-impoverished context showed a better overall level of performance during acquisition. Furthermore, the probe trials revealed that the rats trained and tested in the cue-impoverished context (1) spent less time in the target quadrant at the 25-day delay, and (2) swam shorter distances in the target area, with fewer crossings at both 5- and 25-day delays, as compared to their counterparts trained and tested in the cue-enriched context. Thus, the memory trace formed in the cue-enriched context shows better resistance to time, suggesting an implication of cue saliency in the vividness of a spatial memory.     

Self‐specific Optimism Bias in Belief Updating Is Associated with High Trait Optimism

People learn more from new information when it leads to favorable future outlooks and thus can maintain optimism despite conflicting evidence. In two studies (N = 20 and 26), we investigated whether this optimism bias in belief updating is self‐specific by modifying a recently introduced learning paradigm. In each trial, participants had to estimate the probability of experiencing a negative future event, were then presented with the population base rate of that event, and were subsequently asked for a second, updated estimation. In half of the 88 trials with varying events, estimations were made for oneself, in the other half for a similar other. We tested whether the updates (differences between the first and second estimates) following undesirable base rate were lower than those following desirable base rates, and whether this difference was greater for self relative to other. In both studies, the overall results support the presence of a self‐specific optimism bias in belief updating. However, taking into account trait optimism (TO) as a moderator variable revealed that this was the case only in participants with high TO, whereas those with low TO showed optimistic belief updating for both self and other. In Study 2, we additionally controlled for possible misclassifications of base rate desirability. Taken together, the optimism bias in belief updating was demonstrated by a selective neglect of unfavorable information. A self‐specific influence of this bias in individuals with high TO may ultimately cause the impression of a more positive future outlook relative to others. Copyright © 2014 John Wiley & Sons, Ltd.     

Complete recovery of olfactory associative learning by activation of 5-HT4 receptors after dentate granule cell damage in rats

Bilateral intradentate injections of 3.0 μg of colchicine induced a substantial loss of granule cells and damage to the overlying pyramidal cell layer in region CA1 in adult male Long-Evans rats. All rats with such lesions showed a significant associative learning deficit in an olfactory discrimination task, while being unimpaired in the procedural component of this task. Injection of a partial selective 5-HT₄ agonist (SL65.0155; 0.01 mg/kg, i.p., vs. saline) before the third of six training sessions enabled complete recovery of associative learning performance in the lesioned rats. Activation of 5-HT₄ receptors by a selective agonist such as SL65.0155 might therefore provide an opportunity to reduce learning and memory deficits associated with temporal lobe damage, and could be useful for the symptomatic treatment of memory dysfunctions related to pathological aging such as Alzheimer’s disease.     

Anterior but not intralaminar thalamic nuclei support allocentric spatial memory

Medial thalamic damage is a common cause of severe memory disruption in humans. Both the anterior thalamic nuclei (ATN) and the intralaminar thalamic nuclei (ILN) have been suggested as primary sites of diencephalic injury underlying learning and memory deficits, but their respective roles have yet to be resolved. The present study explicitly compared two spatial memory tasks in male PVGc hooded rats with selective neurotoxic lesions to either (1) the ATN or (2) the rostral ILN (and adjacent lateral mediodorsal thalamic nuclei; ILN/LT lesions). As predicted, the ATN group, but not the ILN/LT group, exhibited clear deficits in the Morris water maze task for the initial acquisition of a fixed hidden platform and its reversal to a new position. The second task examined acquisition of egocentric spatial reference memory for a left or right body turn, using any three arms in an 8-arm water maze on any given trial; contrary to predictions, both lesion groups performed as well as the Sham group. The lack of deficits in ILN/LT rats on this second task contrasted with previous findings reporting a detrimental effect of ILN/LT lesions on egocentric working memory. The clear dissociation between the influence of ATN and ILN/LT lesions with respect to allocentric spatial reference memory in the Morris maze emphasizes that caution is required when interpreting the effects of non-ATN thalamic lesions on spatial memory when the lesions encroach substantial areas of the adjacent ATN region.