The effects of clozapine on delayed spatial alternation deficits in rats with hippocampal damage

Clozapine is an atypical antipsychotic drug that has been shown to improve spatial memory in some animal models; however its efficacy in reversing spatial memory impairment in rats with hippocampal lesions is unknown. To address this issue, we tested the effects of clozapine on delayed spatial alternation deficits in rats with hippocampal damage in three separate experiments. In each experiment, adult male rats received sham surgery or direct stereotaxic infusions of the excitotoxin, NMDA, into the hippocampus. In the first study, seven days after surgery, the sham control animals received daily saline injections while the lesioned animals were split into two groups that received daily saline or clozapine (2.0 mg/kg, sc) injections. During the fifth week of injections, all animals were tested in a food-motivated delayed spatial alternation task. Saline-treated rats with excitotoxic hippocampal damage displayed significant deficits in delayed spatial alternation. Daily clozapine injections completely reversed this deficit. In a second experiment, it was found that clozapine treatment limited to the testing days only did not improve alternation performance in lesioned rats. Finally, in a third experiment, chronic clozapine treatment did not improve alternation performance in lesioned rats that were pre-trained in the alternation task prior to surgery. These results suggest that chronic, but not acute, clozapine treatment enables rats with hippocampal damage to develop new spatial learning, but can not rescue old spatial learning established prior to damage. These results may have implications for the treatment of cognitive deficits caused by hippocampal dysfunction in disorders such as schizophrenia, Alzheimer's disease, and others.     

The Subjective Experience of Being Medicated in Troubled Youth: A Sample from Residential Treatment

The use of psychotropic medications in youth has significantly increased in recent years. Moreover, the use of multiple medications, or polypharmacy, has seen a corresponding increase. The use of medications is largely based on diagnostic impressions and the targeted symptom. However, due to the dearth of applied research with severely troubled youth, there is very little “evidence base” to guide this practice. The Survey of Adolescent Treatment Experience study surveyed youth, currently placed in residential care, on their impressions of medication effectiveness on a wide-range of symptom categories. Youth report only mediocre effectiveness in their medication across a range of symptom questions. Approximately one third of youth indicated that they felt positive about taking medications. On average, slightly less than 50 % of youth reported benefits from medications across symptom categories. It is argued that these findings should inform the efforts toward individualized treatment models.     

Sexism, Vocational Goals, and Motivation as Predictors of Men’s and Women’s Career Choice

In the present study we analyzed the impact of vocational goals, sexist attitudes toward women, and motivation on career choice, in a sample of 448 Spanish college students (65.2% women and 34.1% men). Although we found some similarities between men and women in terms of their motivational orientations (extrinsic vs. intrinsic) and vocational goals, men’s extrinsic motivations appear to differ depending on the college major. We also found differences in sexist attitudes toward women by gender and chosen major: both male and female students enrolled in technical majors reported the most sexist attitudes (both hostile and benevolent). These findings underline the importance of taking sexist attitudes toward women into account in attempts to explain gender differences in career choice, something which has been largely overlooked in the research to date.     

Can brown lemurs (<Emphasis Type="Italic">Eulemur fulvus</Emphasis>) learn to deceive a human competitor?

In the present study we asked whether lemurs could learn to manipulate information in order to deceive a human competitive trainer. Four brown lemurs were trained to communicate about the location of a hidden reward to a cooperative trainer, who rewarded the subject if he indicated the baited bowl. Next, a competitive trainer was introduced who kept the reward for himself if the subject indicated the baited bowl. In a first experiment, sessions were randomly assigned to be with either the cooperative or competitive trainer. No subject was able to show an efficient tactic with both trainers. In a second experiment, the participation of the two trainers was randomized across the trials for each session. When trials were mixed, one subject significantly chose baited location when interacting with the cooperative trainer, and reliably increased his choices of the unbaited location when presented with the competitive trainer. As with most other primate species tested under the same paradigm, associative learning may explain deceptive pointing by lemurs in this study.     

Post-training intrahippocampal injection of synthetic poly-alpha-2,8-sialic acid-neural cell adhesion molecule mimetic peptide improves spatial long-term performance in mice

Several data have shown that the neural cell adhesion molecule (NCAM) is necessary for long-term memory formation and might play a role in the structural reorganization of synapses. The NCAM, encoded by a single gene, is represented by several isoforms that differ with regard to their content of alpha-2,8-linked sialic acid residues (PSA) on their extracellular domain. The carbohydrate PSA is known to promote plasticity, and PSA-NCAM isoforms remain expressed in the CA3 region of the adult hippocampus. In the present study, we investigated the effect on spatial memory consolidation of a PSA gain of function by injecting a PSA mimetic peptide (termed pr2) into the dorsal hippocampus. Mice were subjected to massed training in the spatial version of the water maze. Five hours after the last training session, experimental mice received an injection of pr2, whereas control mice received PBS or reverse peptide injections in the hippocampal CA3 region. Memory retention was tested at different time intervals: 24 h, 1 wk, and 4 wk. The results showed that the post-training infusion of pr2 peptide significantly increases spatial performance whenever it was assessed after the training phase. By contrast, administration of the control reverse peptide did not affect retention performance. These findings provide evidence that (1) PSA-NCAM is involved in memory consolidation processes in the CA3 hippocampal region, and (2) PSA mimetic peptides can facilitate the formation of long-term spatial memory when injected during the memory consolidation phase.     

Perceived deterrence and outcomes in drug court

According to perceived-deterrence theory, the likelihood that an offender will engage in drug use or illegal activity is influenced by the perceived certainty of being detected for infractions or recognized for accomplishments, the perceived certainty of receiving sanctions for infractions or rewards for accomplishments, and the anticipated magnitude of the sanctions and rewards. This study evaluated drug court participants' perceived deterrence at monthly intervals during their enrollment in drug court. Exploratory cluster analysis (N=255) on the longitudinal scores yielded five subtypes of drug offenders characterized either by consistently elevated perceived-deterrence scores, consistently moderate scores, consistently low scores, increasing scores, or decreasing scores. The best outcomes were associated with consistently elevated scores, whereas the worst outcomes were associated with scores that declined over time as the participants became accustomed to the program. The clusters also differed in predicted directions on demographic variables. The correlational design does not permit inferences of causality; however, the results lend credence to perceived deterrence as a potential explanatory mechanism for the effects of drug courts.