Cerebellar dentate nuclei lesions reduce motivation in appetitive operant conditioning and open field exploration

Recently identified pathways from the dentate nuclei of the cerebellum to the rostral cerebral cortex via the thalamus suggest a cerebellar role in frontal and prefrontal non-motor functioning. Disturbance of cerebellar morphology and connectivity, particularly involving these cerebellothalamocortical (CTC) projections, has been implicated in motivational and cognitive deficits. The current study explored the effects of CTC disruption on motivation in male Long Evans rats. The results of two experiments demonstrate that electrolytic lesions of the cerebellar dentate nuclei lower breaking points on an operant conditioning progressive ratio schedule and decrease open field exploration compared to sham controls. Changes occurred in the absence of motor impairment, assessed via lever pressing frequency and rotarod performance. Similar elevated plus maze performances between lesioned and sham animals indicated that anxiety did not influence task performance. Our results demonstrate hedonic and purposive motivational reduction and suggest a CTC role in global motivational processes. These implications are discussed in terms of psychiatric disorders such as schizophrenia and autism, in which cerebellar damage and motivational deficits often present concomitantly.     

Associations of substance use problems with intimate partner violence for at-risk men in long-term relationships

Associations of substance use problems in men--defined as a man's meeting at least 1 criterion of dependence on each of a number of substances by his mid-20s--with their perpetration of intimate partner violence (IPV) were examined in an at-risk community sample of 150 men in long-term relationships from their late adolescence to their late 20s. Men who had a problem with substances other than sedatives (especially cannabis and hallucinogens) committed more IPV than did men without such problems. Most of the men who had a problem with marijuana also had an alcohol problem, which explains why alcohol was found to have only an indirect association with IPV. The failure of previous alcohol-use studies to control for co-occurrence of alcohol and marijuana problems may explain the discrepancy with conclusions from past research that alcohol problems contribute directly to the perpetration of IPV.     

Asymmetric dominance and phantom decoy effects in games

In individual choices between alternatives x and y, the availability of a third alternative z, judged inferior to x but not to y, tends to increase preferences for x. Two experiments investigated corresponding strategic asymmetric dominance effects in games. In Experiment 1, 72 players chose strategies in six symmetric 3 × 3 games, each having one strategy dominating just one other, or in reduced 2 × 2 games constructed by deleting the dominated strategies. Asymmetrically dominated strategies, even when unavailable (phantom decoy), increased choices of the strategies that dominated them and bolstered decision confidence. In Experiment 2, 81 participants played 12 similar but asymmetric games with or without dominated strategies, and similar asymmetric dominance, phantom decoy, and confidence effects were found.     

Staying in or moving away from structured activities: Explanations involving parents and peers

Adolescent participation in structured activities, meaning those with adult leaders, regular meetings, and skill-building activities, is related to good adjustment. Participation in unstructured, unsupervised, peer-oriented activities is related to poor adjustment. Structured activity participation is high in early adolescence and then declines, raising the question of why youths leave structured activities. The authors examined explanations involving parents and peers. They used longitudinal data from 861 youths (ages 13-17 years). Results showed that, compared with youths who stayed in structured activities, those who switched to hanging out on the streets were less likely to have peers in structured activities and had less positive feelings about the home context and more negative interactions with parents. In addition, delinquency predicted switching to hanging out in the streets and never joining structured activities in the first place. The results concerning parents support a theoretical explanation of how parents might unintentionally affect youths' leisure choices. Furthermore, the authors found some indications that positive feelings at home might protect youths who switch from structured activities to hanging out on the streets from increases in delinquency.     

Clinical Effectiveness of the LE<Superscript>3</Superscript>AN Program: A Military Healthy Lifestyle Program

For several decades, obesity has been a major health concern within the general population of the United States as well as within the unique military population. Unlike the civilian sector, military service requires individuals to meet weight and body fat standards. In order to assist overweight military personnel return to standards, Tripler Army Medical Center initiated the LE³AN Program. LE³AN is a one-week, day-treatment, cognitive-behavioral weight management program coupled with 12 months of weekly follow-up. Baseline data was collected on 387 consecutive participants. Despite physical fitness training and required standards in each military service, the average BMIs for men and women were in the obese range, with male participants’ BMIs significantly higher than women’s (34.3 vs 31.9, p<.005). One year outcome data was collected from 167 participants, i.e. 43.2% of treatment initiators. Among participants who completed treatment, men maintained a 6.56% loss of their initial weight while women maintained a 7.35% loss. Over a quarter, 26.6%, of those who started the program (but did not complete it) maintained at least a 5% weight loss at one year, while 61.6% of treatment completers maintained 5% weight losses. The opinions expressed in this article reflect the views of the authors and not those of the Department of Defense or the U.S. Army.     

Life-long environmental enrichment differentially affects the mnemonic response to estrogen in young, middle-aged, and aged female mice

The present study was designed to examine whether life-long exposure to standard or enriched housing affects the ability of estrogen to improve spatial and object memory throughout the lifespan. Three-week-old female mice were maintained in standard or enriched housing up to and through ovariectomy and behavioral testing at 5, 17, or 22 months of age. Spatial memory was tested in the Morris water maze and object memory was tested using an object recognition task. Immediately after training each day, mice were injected intraperitoneally with vehicle or 0.2 mg/kg 17beta-estradiol. Among young females, object recognition was enhanced by estradiol alone, an effect that was reduced by enrichment. In contrast, spatial water maze performance was impaired by estradiol alone, but improved by the combination of both estradiol and enrichment. At middle-age, object recognition was enhanced by estradiol or enrichment alone, and the combination of both treatments. Spatial memory in the water maze was also improved by both treatments at middle-age, but the beneficial effects of estradiol were limited to standard-housed females. Finally, whereas enrichment in aged females significantly enhanced performance in both tasks, estradiol had no effect at this age in either task. In total, the data indicate that life-long enrichment can significantly alter the extent to which estradiol affects memory in mice throughout the lifespan. Importantly, the interaction between these treatments is highly dependent on age and type of memory tested.     

Word-list-learning performance in younger and older adults: intra-individual performance variability and false memory

We investigated the word-list-learning performance of younger and older adults over 4 consecutive days at different times of day to study age-related differences in consistency of performance over time and the influence of circadian variation on performance. Eighteen younger (M age, 23.4 years) and 18 older (M age, 73.3 years) men and women participated. The start time of testing alternated between morning and early evening across the 4 days of testing. On each test day, participants learned a different list of 15 unrelated words over four learning trials. As expected, younger adults performed better than older adults on immediate recall, delayed recall, and recognition. Contrary to our expectations, time of day did not significantly influence recall or recognition performance in either the older or younger adults. Older adults did show a greater incidence of false memory (i.e., previously learned list intrusions in free recall and false alarms in recognition) than younger adults. Older adults also exhibited greater intra-individual performance variability on the measures of false memory across test days. This variability was not related to circadian variation. False memory and variability of performance have both been linked to frontal systems dysfunction. The findings presented here are consistent with the notion that changes in cognition with aging in part reflect age-related decline in frontal lobe function.     

The Sin of Ian McEwan's Fictive Atonement:Reading his Later Novels

Ian McEwan is arguably the best living British novelist. His most successful novel, Atonement , was recently made into an internationally successful film. And indeed, through analysis of his novels, it is clear that Ian McEwan believes literature—precisely as fictive—might very well bear the task of atonement for postmodernity. His novels, though, are patently hopeless, (even as they are truly well-written). Because McEwan doesn't accept or see the causes of sin as such—formally understood as rebellion against the Creator—his diagnostic aesthetic of our postmodern malaise is incomplete and ineffectual. The literary or fictive atonement that he would achieve through his novels does not satisfy. This article aims to lay bare the philosophico-literary characteristics of Ian McEwan's later novels. The ultimate goal of this critical reading, though—tending toward an "evangelical lection"—is to transfigure McEwan's imaginative and creative virtuosity for otherwise disappointed Christian readers, precisely by envisioning his novels in the dark light of their redemptive deficit. Thus, the literary or fictive atonement that Ian McEwan's atheism cannot achieve might be saved apropos the Judeo-Christian revelation of divine atonement.     

Sequelae of Aggression in Acutely Suicidal Adolescents

The consequences of aggression on problem course and suicide risk were examined in 270 acutely suicidal adolescents (ages 12-17 years; 184 girls). Participants were assessed during psychiatric hospitalization (T1), 6-months post-hospitalization (T2), and 15 or more months post-hospitalization (T3). Study variables included self- and parent-reported aggression; self-reported internalizing symptoms, suicidal ideation, suicide attempt, and adverse events; and clinician-rated suicidal behavior. Aggression was not directly related to suicide attempt concurrently or prospectively. However, among more aggressive youth, internalizing symptoms were more predictive of T3 suicide attempt than among less aggressive youth. T1 aggression predicted aggressive incidents and the likelihood of incarceration prior to T3. Two-level hierarchical linear modeling indicated that self-reported aggression and internalizing problems were linked in terms of severity and rates of decline over time. Overall, parent-reported aggression was negatively associated with suicidal ideation. Findings highlight (a) the continuity and consequences of aggression, (b) a possible role of aggression in worsening suicide risk factors and potentiating suicide attempt, and (c) the importance of ongoing research on subtypes of suicidal adolescents.