MK-801 improves retention in aged rats: implications for altered neural plasticity in age-related memory deficits

Alterations in N-methyl-d-aspartate receptor (NMDAR)-dependent synaptic plasticity, characteristic of aged rodents, may contribute to impaired memory with advanced age. The purpose of the current research was to examine whether NMDARs contribute to rapid forgetting on a spatial memory task. Aged (22-24 months) and adult (3-6 months) male Fischer 344 rats received 18 training trials, over a period of 3 to 4 h, on the spatial version of the Morris water maze. Immediately after training, a standard free-swim probe trial was administered to assess the acquisition of spatial bias, which was determined by the percent of time spent in the goal quadrant and the number of platform crossings. Rats then received injections of the noncompetitive NMDAR antagonist, (+)-10, 11-dihydro-5methyl-5H-dibenzo(a,b)cycloheptene-5,10 imine (MK-801, 0. 05 mg/kg, i.p.), or a vehicle injection of equal volume. Approximately 24 h later, rats were administered a second free-swim probe trial to assess retention of spatial bias. All age/drug groups exhibited a spatial bias on the acquisition probe, with adults generally outperforming the aged rats. On the retention probe, this spatial bias continued to be shown by adult rats, regardless of treatment. For the aged group, in contrast, only MK-801-injected rats maintained a spatial bias on the retention probe, suggesting that NMDAR activity may be involved in rapid forgetting during aging. Because blockade of NMDARs also may impair new learning, which may, in turn, protect previously stored information from retroactive interference, rats in a second experiment received post-training injections of scopolamine (0.05 mg/kg), a compound known to inhibit learning. However, scopolamine did not enhance retention in the aged group, consistent with the hypothesis that MK-801 influenced memory in aged rats through its actions on NMDAR-dependent synaptic plasticity.     

斯图亚特·霍尔与英国马克思主义

斯图亚特.霍尔不仅是英国文化马克思主义的开创者,而且还是当今社会批判理论的过渡性人物,其思想发展大致可分为三个阶段:1956-1964年为第一阶段,这一阶段霍加特、汤普森和威廉斯对其思想产生了重要影响;1964-1978年为第二阶段,这一时期霍尔主要吸收了阿尔都塞的结构主义、葛兰西的霸权主义以及符号学理论;1970年代末以后,霍尔开始以一名公共知识分子的形象活跃于多个理论前沿。在文章的末尾,作者还对"本土化的马克思主义"这一提法提出了质疑,认为它取消了英国性这一问题,从而存在着与主流意识形态话语同谋的危险。     

Activation of brain attention systems in individuals with symptoms of ADHD

Previous research investigating attention and impulse control in individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) has largely ignored the symptomatic differences among the three subtypes of ADHD: ADHD-Inattentive Type, ADHD-Hyperactive/Impulsive Type, and ADHD-Combined Type. The present study examined attention and impulse control by focusing on these subtypes. Based on their self-reported symptoms of ADHD, participants belonged to one of four groups: ADHD-Inattentive, ADHD-Hyperactive/Impulsive, ADHD-Combined, and control. Cortical activity was recorded from participants during performance of a Go/NoGo task. The event-related potentials (ERP) measured at frontal and posterior sites discriminated between the control group and participants with symptoms of ADHD. The control group consistently exhibited a higher P3 amplitude than all the ADHD groups. The main difference occurred at the frontal site, indicating that individuals with ADHD symptoms have deficits in the anterior attentional system, which mediates signal detection. Behavioral measures of signal sensitivity revealed that the ADHD-Inattentive and the ADHD-Hyperactive/Impulsive groups had more difficulty with the attention-demanding Go/NoGo respond-to-target task, while behavioral measures of response bias indicated that the ADHD-Hyperactive/Impulsive and the ADHD-Combined groups responded more liberally in the inhibition-demanding Go/NoGo suppress-to-target task.     

The impact of continuing care adherence on environmental risks, substance use, and substance-related problems following adolescent residential treatment.

The effectiveness of adolescent treatment to reduce substance use has been demonstrated by a number of different literature reviews, yet longer term outcome studies have suggested that continued alcohol and other drug use is common. Participation in continuing care services and reductions in environmental risk factors (e.g., peer substance use or alcohol or drug use in the home) have both been found to be associated with improved posttreatment substance use. The authors conducted Path analysis to examine the experimental direct effect of the Assertive Continuing Care Protocol (S. H. Godley, M. D. Godley, & M. L. Dennis, 2001) on general continuing care adherence following residential treatment and the protocol's indirect effect (via general continuing care adherence) on social and environmental risk factors, as well as subsequent substance use and substance-related problems. Supporting previous findings, the final model indicates that greater adherence to continuing care is associated with reductions in environmental risk, which in turn is associated with reduced adolescent substance use and substance-related problems 9 months after discharge from residential treatment.     

Employing community data to investigate social and structural dimensions of urban neighborhoods: An early childhood education example

The present study sought to define neighborhood context by examining relationships among data from city-level administrative databases at the level of the census block group. The present neighborhood investigation included 1,801 block groups comprising a large, northeastern metropolitan area. Common factor analyses and multistage, hierarchical cluster analyses yielded two dimensions (i.e., Social Stress, Structural Danger) and two typologies (i.e., Racial Composition, Property Structure Composition) of neighborhood context. Simultaneous multiple regression analyses revealed small but statistically significant associations between neighborhood variables and academic outcomes for public school kindergarten children.     

Attending to diversity in group psychotherapy: an ethical imperative

Ethical issues can arise in dealing with diversity when practicing group psychotherapy. In this paper, a case is presented of a therapist-in-training who is attempting to determine whether a particular psychotherapy group composed exclusively of heterosexual males would be an appropriate and effective treatment venue for a gay male; the clinical vignette is designed to illustrate a process of ethical and culturally competent decision making. The discussion of this vignette articulates the multiple steps through which the group psychotherapist must proceed to successfully resolve ethical dilemmas that are related to diversity.     

A Kantian moral duty for the soon-to-be demented to commit suicide

It has been argued that, on Kantian grounds, pedophiles, rapists and murderers are morally obligated to take their own lives prior to committing a violent action that will end their moral agency. That is, to avoid destroying the agent's moral life by performing a morally suicidal action, the agent, while he still is a moral agent, should end his body's life. Although the cases of dementia and the morally reprehensible are vastly different, this Kantian interpretation might be useful in the debate on the permissibility of suicide for those facing dementia's effects. If moral agents have a duty to act as moral agents, then those who will lose their moral identity as moral agents have an obligation to themselves to end their physical lives prior to losing their dignity as persons.