Emotional stimuli and context moderate effects of nicotine on specific but not global affects.

The authors tested the hypothesis that the effects of nicotine on affect are moderated by the presence or absence of emotionally positive and negative stimuli and by attentional choice to avoid attending to emotionally negative stimuli. Thirty-two habitual smokers were assigned to tasks allowing attentional freedom to look back and forth at 2 simultaneously presented pictures, whereas another 32 habitual smokers viewed single pictures without attentional choice. Picture contents in both tasks were 1 of 4 combinations: emotionally negative + neutral, negative + positive, positive + neutral, or neutral + neutral. Participants wore a nicotine patch on 1 day and placebo patch on another day. Nicotine reduced anxiety most when negative pictures were presented in combination with neutral pictures, but it had no effect on anxiety when negative pictures were presented in combination with positive pictures and when negative pictures were not presented. In contrast, nicotine only reduced depressive affect when the participant had attentional choice between positive and negative pictures. Nicotine also enhanced positive affect and reduced negative affect as measured by the Positive and Negative Affect Schedule, but these effects were not moderated by task manipulations. Overall, the findings support the view that nicotine's ability to reduce specific negative affects is moderated by emotional context and attentional freedom. Nicotine tended to enhance eye-gaze orientation to emotional pictures versus neutral pictures in women, but it had no significant effect on eye-gaze in men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The separate and combined effects of nicotine and alcohol on working memory capacity in nonabstinent smokers.

Research indicates that nicotine and alcohol are often used on the same occasion. However, the reasons for their concurrent use are not well understood. We hypothesized that one reason smokers use tobacco when they drink alcohol is to compensate for alcohol’s negative effects on processing capacity with nicotine’s enhancement of processing capacity. As such, the present study tested this theory by using an independent groups design to examine the separate and combined acute effects of alcohol and nicotine on working memory (WM) capacity. Nonabstinent daily smokers (n = 127) performed the counting span task (CSPAN) after consuming either an alcohol (men: 0.8 g/kg; women: 0.7 g/kg) or placebo beverage and smoking either nicotinized (1.14 mg nicotine, 15.9 mg tar) or denicotinized (.06 mg nicotine, 17.9 mg tar) cigarettes. Analyses revealed that smokers who smoked the nicotinized cigarettes performed significantly worse on the CSPAN task than smokers who smoked the denicotinized cigarettes. Although there was no main effect of alcohol on WM performance, women exhibited better WM performance than men after consuming alcohol whereas men performed better than women on the WM task after consuming the placebo beverage. Findings also revealed no interaction between the two substances on WM performance. Taken together, results suggest that nicotine impairs nonabstinent smokers’ verbal WM capacity and that gender moderates the effects of alcohol on WM. Furthermore, the present findings failed to support the notion that nicotine compensates for alcohol-related decrements in working memory capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of nicotine and depressive traits on affective priming of lateralized emotional word identification.

Based on evidence suggesting that depressive traits, emotional information processing, and the effects of nicotine may be mediated by lateralized brain mechanisms, analyses assessed the influence of depressive traits and nicotine patch on emotional priming of lateralized emotional word identification in 61 habitual smokers. Consistent with hypotheses, nicotine as compared to placebo patch enhanced right visual field (RVF) emotional word identification while decreasing performance of emotional word identification in the left visual field (LVF). Nicotine also enhanced positive affect and decreased negative affect. Consistent with the Heller model of depression, scoring high in depressive traits was associated with a general decrease in LVF emotional word identification. Additionally, this general LVF deficit was especially pronounced for positive word identification in individuals scoring high in trait depression. Positive primes facilitated positive target identification in the RVF and negative primes facilitated negative target identification in the LVF. Thus, nicotine promoted a LVF word-identification deficit similar to that observed in those with depressive traits. However, nicotine also enhanced RVF processing and reduced negative affect, whereas it enhanced positive affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of working memory in spatial S-R correspondence effects.

This study investigates the impact of working memory (WM) load on response conflicts arising from spatial (non) correspondence between irrelevant stimulus location and response location (Simon effect). The dominant view attributes the Simon effect to automatic processes of location-based response priming. The automaticity view predicts insensitivity of the Simon effect to manipulations of processing load. Four experiments investigated the role of spatial and verbal WM in horizontal and vertical Simon tasks by using a dual-task approach. Participants maintained different amounts of spatial or verbal information in WM while performing a horizontal or vertical Simon task. Results showed that high load generally decreased, and sometimes eliminated, the Simon effect. It is interesting to note that spatial load had a larger impact than verbal load on the horizontal Simon effect, whereas verbal load had a larger impact than spatial load on the vertical Simon effect. The results highlight the role of WM as the perception-action interface in choice-response tasks. Moreover, the results suggest spatial coding of horizontal stimulus-response (S-R) tasks, and verbal coding of vertical S-R tasks. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

BDNF genotype moderates the relation between physical activity and depressive symptoms.

Objective: To test whether the BDNF gene interacts with exercise to predict depressive symptoms. Physical activity is associated with a range of positive health outcomes, including fewer depressive symptoms. One plausible mechanism underlying these findings involves Brain-Derived Neurotrophic Factor (BDNF), a protein hypothesized to limit or repair the damage caused by stress. Physical activity increases expression of BDNF, which may enhance brain health. BDNF expression is controlled by the BDNF gene. Compared with individuals without a BDNF met allele, met-allele carriers have a lower expression of BDNF, which has been associated with Major Depressive Disorder. Design: Eighty-two healthy adolescent girls were genotyped for the BDNF val66met polymorphism, and their depressive symptoms and physical activity were assessed using questionnaires. Main Outcome Measures: BDNF genotype, Children’s Depression Inventory, and the Physical Activity Questionnaire for Older Children and Adolescents. Results: The BDNF polymorphism was found to moderate the relation between exercise and depressive symptoms: being physically active was protective for girls with a BDNF met allele (fewer depressive symptoms) but not for girls with the val/val polymorphism. Conclusion: By integrating psychological and biological factors, the present study enhances our understanding of how physical activity contributes to resilience to psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of smoking and smoking abstinence on verbal and visuospatial working memory capacity.

Several studies have examined the effects of smoking and abstaining from smoking on working memory (WM) but have yielded inconclusive findings. Thus, the authors used a repeated measures design to assess the effects of smoking and abstaining from smoking on both visuospatial and verbal WM capacity (WMC) using highly reliable, well-validated, and theoretically driven WM span tasks. Verbal n-back was also administered to examine its relationship to these complex WM span tasks and to compare this study's results with previous findings. Smokers (n = 23) and nonsmokers (n = 21) participated in 2 sessions separated by 1 week. During 1 session, smokers completed the WM tasks after abstaining from smoking for at least 12 hr, whereas in the other session smokers did not abstain from smoking and were tested immediately after smoking (all WM tasks were completed 45 min or less since last cigarette). Results indicated that smokers' verbal WM span was lower than nonsmokers' and was lower during the nonabstinent session compared with the abstinent session. Smokers' verbal n-back performance was also lower than nonsmokers', although there was no difference in verbal n-back performance between the smoking sessions. In contrast, there was no difference in visuospatial WM span between the smoking sessions or between smokers and nonsmokers. Taken together, these findings demonstrate that (a) smokers' verbal WM is lower than nonsmokers, (b) smokers' verbal WMC is lower during nonabstinence compared with abstinence, and (c) smoking exhibits differential effects on the different WM domains. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neurotransmission-related genetic polymorphisms, negative affectivity traits, and gender predict tobacco abstinence symptoms across 44 days with and without nicotine patch.

Genetic and personality trait moderators of tobacco abstinence–symptom trajectories were assessed in a highly controlled study. Based on evidence suggesting their importance in stress reactivity and smoking, moderators studied were serotonin transporter gene (5-HTTLPR) and dopamine D2 receptor gene (DRD2) polymorphisms and personality traits related to negative affect (NA). Smokers were randomly assigned to quit smoking with nicotine or placebo patches. Financial incentives resulted in 80% verified abstinence across the 44-day study. Individuals with 1 or 2 short alleles of 5-HTTLPR (S carriers) experienced larger increases in NA symptoms than did those without a short allele. Nicotine replacement therapy (NRT) alleviated anxiety only in S carriers. NRT reduced NA to a greater extent in DRD2 A1 carriers than in A2A2 individuals during the 1st 2 weeks of treatment (when on the 21-mg patch); however, A1 carriers experienced a renewal of NA symptoms when switched to the 7-mg patch and when off the patch, while A2A2 individuals continued to benefit from NRT. The results suggest that the effects of genotype and treatment may vary across different durations of abstinence, treatment doses, and genotypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remembrance of places you passed: Social spatial working memory in rats.

Pairs of rats were tested in a radial-arm maze to determine whether the spatial choices made by one rat affect the subsequent spatial choices of the other rat. In a free-choice procedure, rats showed an increased tendency to choose the location that had most recently been chosen by a foraging partner but a decreased tendency to visit locations that the foraging partner had visited earlier. Forced-choice procedures were used to better control the social stimulus and the interactions between the rats. Under some conditions, locations were chosen later in the choice sequence of a subject rat if another rat had been observed choosing that location. Odor and other physical traces of the other rat's visits were ruled out as explanations for this effect. The results demonstrate the existence of working memory for locations visited by a familiar conspecific. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-dose transdermal nicotine and naltrexone: Effects on nicotine withdrawal, urges, smoking, and effects of smoking.

Although treatment with transdermal nicotine replacement (TNR) has improved smoking abstinence rates, higher doses of TNR could improve effects on urge to smoke, nicotine withdrawal, and reinforcement from smoking, and naltrexone might further reduce reinforcement and urges. A laboratory investigation with 134 smokers using a 3 × 2 parallel-group design evaluated the effects of TNR (42-mg, 21-mg, or 0-mg patch) as crossed with a single dose of naltrexone (50 mg) versus placebo on urge to smoke, withdrawal, and responses to an opportunity to smoke (intake, subjective effects) after 10 hr of deprivation. Urge and withdrawal were assessed both prior to and after cigarette cue exposure. Only 42 mg TNR, not 21 mg, prevented urge to smoke, heart rate change, and cue-elicited increase in withdrawal. Both 21 and 42 mg TNR blocked cue-elicited drop in heart rate and arterial pressure. Naltrexone reduced cue-elicited withdrawal symptoms but not urges to smoke or deprivation-induced withdrawal prior to cue exposure. Neither medication significantly affected carbon monoxide intake or subjective effects of smoking except that 42 mg TNR resulted in lower subjective physiological activation. No interaction effects were found, and no results differed by gender. Results suggest that starting smokers with 42 mg TNR may increase comfort during initial abstinence, but limited support is seen for naltrexone during smoking abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit memory for spatial context in depression and schizophrenia.

Deficits in explicit spatial memory, as well as abnormalities of the hippocampus and neighboring medial temporal structures, have been documented in schizophrenia and depression. Recent evidence relying on the contextual cueing paradigm has shown that integrity of these structures is crucial not only for explicit memory but also for implicit spatial memory. Using this paradigm, the authors show that implicit memory for spatial context is severely impaired in clinically depressed patients but reaches a normal level in schizophrenia patients, although in these patients, acquisition is slower than in controls. By contrast, implicit memory for isolated locations and colors is normal in both schizophrenia and depressed patients. These findings suggest an implicit memory impairment specific to spatial context in depression. The implications for research on the differences between schizophrenia and depression in abnormalities of the hippocampal system and for research on the neural correlates of contextual cueing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of transdermal nicotine on tobacco/nicotine abstinence and the effects of a concurrently administered cigarette in women and men.

Transdermal nicotine (TN) is an efficacious smoking cessation pharmacotherapy thought to work, in part, by attenuating the effects of tobacco/nicotine abstinence and the effects of concurrently smoked cigarettes. Clinical trials suggest that TN may be less efficacious for women. This study explored the possibility of TN-related gender differences in ≥8 hour abstinent smokers (54 women, 70 men) who completed four within-subject, double-blind, placebo-controlled sessions corresponding to 0, 7, 14, and 21 mg TN. In each approximately 6.5-hr long session participants smoked an own-brand cigarette 4 hours after TN administration and physiological and subjective outcomes were examined throughout each session. Results revealed that TN suppressed some signs and symptoms of tobacco abstinence and attenuated some effects of smoking, and these effects were not dependent on gender. Women were more sensitive to the direct effects of nicotine (e.g., ratings of Nauseous) and, independent of TN dose, self-administered less nicotine when smoking and rated smoking as less rewarding. Thus, although this study does not shed light on clinical observations that TN is less effective for women, results suggest that TN might need to be combined with other interventions to supplement its effects on tobacco/nicotine abstinence and concurrent smoking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association of the serotonin transporter gene promoter region (5-HTTLPR) polymorphism with biased attention for emotional stimuli.

A deletion polymorphism in the serotonin transporter-linked polymorphic region (5-HTTLPR) has been associated with vulnerability to affective disorders, yet the mechanism by which this gene confers vulnerability remains unclear. Two studies examined associations between the 5-HTTLPR polymorphism and attentional bias for emotional stimuli among nondepressed adults. Biased attention, attention engagement, and difficulty with attention disengagement were assessed with a spatial cuing task using emotional stimuli. Results from Study 1 (N = 38) indicated that short 5-HTTLPR allele carriers experienced greater difficulty disengaging their attention from sad and happy stimuli compared with long allele homozygotes. Study 2 participants (N = 144) were genotyped for the 5-HTTLPR polymorphism, including single nucleotide polymorphism rs25531 in the long allele of the 5-HTTLPR. Consistent with Study 1, individuals homozygous for the low-expressing 5-HTTLPR alleles (i.e., S and LG) experienced greater difficulty disengaging attention from sad, happy, and fear stimuli than high-expressing 5-HTTLPR homozygotes. Because this association exists in healthy adults, it may represent a susceptibility factor for affective disorders that becomes problematic during stressful life experiences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Body- and environmental-stabilized processing of spatial knowledge.

In 5 experiments, the authors examined the perceptual and cognitive processes used to track the locations of objects during locomotion. Participants learned locations of 9 objects on the outer part of a turntable from a single viewpoint while standing in the middle of the turntable. They subsequently pointed to objects while facing the learning heading and a new heading, using imagined headings that corresponded to their current actual body heading and the other actual heading. Participants in 4 experiments were asked to imagine that the objects moved with them as they turned and were shown or only told that the objects would move with them; in Experiment 5, participants were shown that objects could move with them but were asked to ignore this as they turned. Results showed that participants tracked object locations as though the objects moved with them when shown but not when told about the consequences of their locomotion. Once activated, this processing mode could not be suppressed by instructions. Results indicated that people process object locations in a body- or an environment-stabilized manner during locomotion, depending on the perceptual consequences of locomotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal effects of conflict behaviors on depressive symptoms in young couples.

This study investigated relationship dynamics contributing to gender differences in depression by testing longitudinal associations between observed conflict behaviors and depressive symptoms in young couples. Direct effects of psychological aggression, positive engagement, and withdrawal, as well as indirect effects via relationship satisfaction were considered. Participants were 68 heterosexual couples involving men from the Oregon Youth Study who remained in a stable relationship across at least 2 and up to 10 years from their early 20s to early 30s. Hierarchical linear modeling was used to test both between-couples differences in symptom trajectories predicted by partner behaviors and within-couple covariation between behaviors and depressive symptoms across 5 time points. Higher levels of women’s positive engagement predicted lower symptom levels for both partners, and higher women’s withdrawal predicted higher own symptom levels. Relative increases in couples’ psychological aggression and decreases in positive engagement were additionally associated with increases in women’s symptoms over time. Whereas between-couples behavior effects on women’s symptoms were mediated by relationship satisfaction, within-couple effects proved independent of satisfaction. Implications for mechanisms of depression risk and maintenance in couples are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tests of the dynamic field theory and the spatial precision hypothesis: Capturing a qualitative developmental transition in spatial working memory.

This study tested a dynamic field theory (DFT) of spatial working memory and an associated spatial precision hypothesis (SPH). Between 3 and 6 years of age, there is a qualitative shift in how children use reference axes to remember locations: 3-year-olds’ spatial recall responses are biased toward reference axes after short memory delays, whereas 6-year-olds’ responses are biased away from reference axes. According to the DFT and the SPH, quantitative improvements over development in the precision of excitatory and inhibitory working memory processes lead to this qualitative shift. Simulations of the DFT in Experiment 1 predict that improvements in precision should cause the spatial range of targets attracted toward a reference axis to narrow gradually over development, with repulsion emerging and gradually increasing until responses to most targets show biases away from the axis. Results from Experiment 2 with 3- to 5-year-olds support these predictions. Simulations of the DFT in Experiment 3 quantitatively fit the empirical results and offer insights into the neural processes underlying this developmental change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of nicotine dose and nicotine dose expectancy on the cognitive and subjective effects of cigarette smoking.

This study investigated the independent and interactive effects of nicotine dose and nicotine dose expectancy on smoking outcomes using a 2 (given nicotine vs. placebo) × 2 (told nicotine vs. placebo) Balanced Placebo Design (BPD). Smokers (N = 148) completed the Rapid Visual Information Processing Task (RVIP) and measures of smoking urge, mood, and cigarette ratings (e.g., satisfying) after smoking a nicotine or placebo cigarette crossed with instructions that the cigarette contained either nicotine or no nicotine. Nicotine cigarettes (0.6 mg nicotine) produced better sustained attention performance than placebos as indicated by RVIP reaction time, hits, and sensitivity (A′). Nicotine cigarettes also produced better mood and greater rewarding subjective effects of the cigarettes on 11 of 11 dimensions compared to placebos. Nicotine instructions resulted in fewer RVIP false alarms, better mood, and greater rewarding subjective effects of the cigarettes on 9 of 11 dimensions compared to placebo instructions. Nicotine dose by nicotine dose expectancy interactions were also observed for urge and tension-anxiety, such that the dose expectancy manipulation produced differential effects only among those who smoked placebo cigarettes. In contrast a significant interaction for self-reported vigor-activity demonstrated that the dose expectancy manipulation produced effects only among those who smoked nicotine cigarettes. This study provides additional evidence that nicotine improves cognitive performance, and provides initial evidence that denicotinized cigarettes smoked under the guise that they contain nicotine influence cognitive performance, albeit with less robust effects than nicotine. These data may inform the development of expectancy-based interventions for tobacco dependence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Long-term study of chronic oral aluminum exposure and spatial working memory in rats.

The authors report an effort to advance animal models that mimic the cognitive decline of Alzheimer's disease. Rats were trained and repeatedly tested in a spatial delayed matching-to-position paradigm in the water maze, with the location of the submerged platform changing between, but not within, days. After Trial 1 (random search) and intertrial intervals of 30 s or 1 hr, memory was tested in Trial 2. Young rats quickly acquired this task and were repeatedly tested after different intervals over 7 months, with a slight increase in performance toward the end of testing, but no difference in latencies between delays. Oral long-term treatment of 1 group with 0.1 % aluminum caused no delay-dependent working memory deficit. This testing protocol may enable between- and within-subject long-term assessment of spatial working memory before and after drug treatment and may prove useful in animal models of progressive cognitive decline. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interference effects by spatial proximity and age-related declines in spatial memory by Japanese monkeys (Macaca fuscata): Deficits in the combined use of multiple spatial cues.

Spatial information processing was assessed in 3 young (4-10 years old) and 4 aged (24-25 years old) Japanese monkeys (Macaca fuscata) on 3 delayed nonmatching-to-position (DNMP) tests with relatively short delays of 5 s. Each test had 3 conditions of different horizontal distances between sample and to-be-nonmatched positions. Experiment 1 demonstrated that the performance on the DNMP test in both age groups was impaired when 2 stimulus positions were located next to each other; however, it was fairly accurate when they were located farther apart, suggesting that interference is introduced by spatial proximity. Experiment 2 revealed age-related differences in the situation in which an additional spatial cue, depth information, was available by extending the stimulus array of the DNMP test to a 4 = 2 matrix. In this test, young monkeys performed accurately irrespective of position distance between stimuli, whereas the aged monkeys' performance remained the same as before. Experiment 3 confirmed that the recognition ability in aged monkeys was well preserved on DNMP tests with different objects. These patterns of results indicate that the ability to use information from multiple spatial cues is not accessible to the aged monkeys. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Revisiting the effect of marital support on depressive symptoms in mothers and fathers: A genetically informed study.

This article uses a genetically informed design to evaluate whether (1) the well-documented association between marital support and depressive symptoms is accounted for by genetic and/or shared environmental selection, (2) gender differences are found after controlling for selection effects, and (3) parenthood moderates any nonshared environmental relation between depressive symptoms and marital support. We used a sample of 1,566 pairs of same-sexed, married twins from the Australian Twin Registry to evaluate our hypotheses that (1) the predicted effect of marital support on depressive symptoms is not fully an artifact of selection, (2) the etiological sources accounting for this effect differ between husbands and wives, and (3) parenthood status moderates the effect of marital support on depressive symptoms adjusting for selection effects. The results support the first hypotheses. However, after controlling for selection, the effect of marital support on depressive symptoms was not significantly different for husbands and wives. Parenthood moderated the effect of marital support, such that after controlling for selection, marital support is more strongly associated with depressive symptoms for full-time parents than nonfull-time parents. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Combined effects of venlafaxine, nicotine replacement, and brief counseling on smoking cessation.

In this study, 147 smokers were randomly assigned to receive either venlafaxine or placebo in conjunction with behavioral counseling (9 weekly sessions) and transdermal nicotine replacement therapy (22 mg/day). Patients began medication 2 weeks before quitting and continued for 18 weeks after quitting, with the daily dose titrated from 150 to 225 mg. in response to symptoms of negative affect and relapse. The results showed no main effect of treatment on abstinence. Post hoc analysis revealed that both at the end of treatment and at the 1-year follow-up smokers consuming less than a pack of cigarettes a day benefited from the addition of venlafaxine to the treatment regimen. Venlafaxine also reduced negative affect for all smokers for up to 6 weeks postcessation. The findings suggest that venlafaxine could have some role to play in the treatment of lighter smokers, in addition to the expected benefits of nicotine replacement therapy and behavioral counseling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)