Modulation of phencyclidine-induced changes in locomotor activity and patterns in rats by serotonin

Membrane-expressed immunoglobulins are B-cell receptors (BCR) for specific antigens (Ag). Upon Ag engagement of the BCR, B-cells are activated to internalize Ag-BCR complexes, process Ag and subsequently present Ag-peptides loaded in class II MHC. Due to the specific nature of the BCR, the cognate interaction between T-cells expressing Ag-specific T-cell receptor and these Ag-presenting B-cells occur in a highly regulated and precise manner. Accordingly, efficient control of T-cell activation may be achieved through regulation of Ag presenting B-cells. A potent form of regulation of lymphocyte responses is mediated by Ig end-product and anti-idiotypic antibodies via Fc-dependent mechanisms. In this communication, the authors present data that an anti-idiotype (anti-Id) Ab inhibits BCR-mediated internalization of specific Ag. Coupling of BCR to the cytoskeleton was also abortive in anti-Id Ab-treated B-cells. Inhibition by anti-Id Ab was dependent upon the presence of FcgammaRIIB1 on B-cells. As a result of anti-Id Ab suppression, B-cells were unable to initiate Ca2+ responses in Ag-specific T-cells. The results suggest that co-crosslinking of FcgammaRIIB1 and BCR inhibits cytoskeletal coupling and internalization of the Ag-BCR complex thereby preventing specific Ag presentation by B-cells. Anti-Id Ab may mediate a negative regulatory mechanism that suppresses B-cell-mediated Ag-specific T-cell activation.     

Selective serotonin receptor stimulation of the medial nucleus accumbens causes differential effects on food intake and locomotion.

Substantial evidence suggests that pharmacological manipulations of neural serotonin pathways influence ingestive behaviors. Despite the known role of the nucleus accumbens in directing appetitive and consummatory behavior, there has been little examination of the influences that serotonin receptors may play in modulating feeding within nucleus accumbens circuitry. In these experiments, the authors examined the effects of bilateral nucleus accumbens infusions of the 5-HT1/7 receptor agonist 5-CT (at 0.0, 0.5, 1.0, or 4.0 μg/0.5 μl/side), the 5-HT? receptor agonist EMD 386088 (at 0.0, 1.0, and 4.0 μg/0.5 μl/side), or the 5-HT2C preferential agonist RO 60–0175 (at 0.0, 2.0, or 5.0 μg/0.5 μl/side) on food intake and locomotor activity in the rat. Intra-accumbens infusions of 5-CT caused a dose-dependent reduction of food intake and rearing behavior, both in food-restricted animals given 2-hr free access to Purina Protab RMH 3000 Chow, as well as in nondeprived rats offered 2-hr access to a highly palatable fat/sucrose diet. In contrast, stimulation of 5-HT? receptors with EMD 386088 caused a dose-dependent increase of intake under both feeding conditions, without affecting measures of locomotion. Infusions of the moderately selective 5-HT2C receptor agonist RO 60–0175 had no effects on feeding or locomotor measures in food-restricted animals, but did reduce intake of the fat/sucrose in nonrestricted animals at the 2.0 μg, but not the 5.0 μg dose. Intra-accumbens infusions of selective antagonists for the 5-HT? (SB 269970), 5-HT? (SB 252585), and 5-HT2C (RS 102221) receptors did not affect locomotion, and demonstrated no lasting changes in feeding for any of the groups tested. These data are the first to suggest that the activation of different serotonin receptor subtypes within the feeding circuitry of the medial nucleus accumbens differentially influence consummatory behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The causal role of interpretive bias in anxiety reactivity.

Elevated anxiety vulnerability is associated with a tendency to interpret ambiguous stimuli as threatening, but the causal basis of this relationship has not been established. Recently, procedures have been developed to systematically manipulate interpretive bias, but the impact of such manipulation on anxiety reactivity to a subsequent stressor has not yet been examined. In the present study, training procedures were used to induce interpretive biases favoring the threatening or nonthreatening meanings of ambiguous information in a sample of 48 undergraduate students. Following this interpretive training, participants' emotional reactions to a stressful video were assessed. The finding that the manipulation of interpretive bias modified emotional reactivity supports the hypothesis that interpretive bias can indeed play a causal role in anxiety vulnerability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of the role of medial prefrontal cortex dopamine receptors in cocaine-induced locomotor activity.

Medial prefrontal cortex (mPFC) dopamine (DA) modulates the motor-stimulant response to cocaine. The present study examined the specific mPFC DA receptor subtypes that mediate this behavioral response. Intra-mPFC injection of the DA D?-like receptor agonist quinpirole blocked cocaine-induced motor activity, an effect that was prevented by coadministration of the D2 receptor antagonist sulpiride. Intra-mPFC injection of the selective D? receptor agonist PD 168,077 or the selective D? receptor agonist SKF 81297 did not alter the motor-stimulant response to cocaine. Finally, it was found that an intermediate dose of quinpirole, which only attenuated cocaine-induced motor activity, was not altered by SKF 81297 coadministration, suggesting a lack of synergy between mPFC D?, and D? receptors. These results suggest that D? receptor mechanisms in the mPFC are at least partly responsible for mediating the acute motor-stimulant effects of cocaine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationship between a measure of transitory anxiety and spontaneous autonomic activity.

The effects of stress (threat of shock) on GSR nonspecific responses were evaluated for Ss who differed in transitory anxiety as measured by the Affect Adjective Check List (AACL). 52 Ss were equally divided among 4 groups: Hi AACL Stress, Lo AACL Stress, Hi AACL Nonstress, and Lo AACL Nonstress. 1st, all Ss rested; then both Stress groups were threatened with shock, while both Nonstress groups continued resting; finally, all Ss rested again. During the 2nd period GSR nonspecifics increased for both stress groups; however, during the final period, after the cessation of stress, GSR nonspecifics decreased more for the Lo AACL Ss than for the Hi AACL Ss. It was concluded that the AACL may be related to "autonomic recovery rate." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of GABA and anxiety in the reconsolidation of conditioned fear.

The current study examined the effects of systemic administration of a GABA agonist [midazolam (MDZ)] and a GABA antagonist (bicuculline) on fear responding after brief CS exposure, a procedure thought to involve memory reconsolidation. Using a contextual fear-conditioning paradigm, rats were initially given two context-shock training trials, followed 24 hrs later by a 90-s context exposure (reactivation), and 24 hrs later by a 3-min context test. In Experiment 1, MDZ (2 mg/kg, i.p.), whereas in Experiment 2, bicuculline (1 mg/kg, i.p.), was administered immediately after reactivation. MDZ reduced conditioned freezing, whereas bicuculline only marginally potentiated conditioned freezing. The MDZ fear disruption effect did not occur in the absence of reactivation, and was evident 10 days after the initial test. Experiment 3 induced high levels of baseline anxiety using the single prolonged stress paradigm, and replicated the essential procedure of Experiment 1. Results indicated that MDZ fear disruption did not differ between high and low anxiety rats. The data suggest the involvement of GABA receptors in reconsolidation processes, and the possible clinical use of MDZ in fear reduction with brief reexposure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of defeat and entrapment in depression, anxiety, and suicide.

Defeat and entrapment are psychological constructs that have played a central role in evolutionary accounts of depression. These concepts have since been implicated in theoretical accounts of anxiety disorders and suicidality. The current article reports on a systematic review of the existing research investigating the links among defeat, entrapment, and psychopathology in the domains of depression, suicidality, posttraumatic stress disorder (PTSD), and other anxiety syndromes. Fifty-one original research articles were identified and critically reviewed. There was strong convergent evidence for a link with depressive symptoms, across a variety of clinical and nonclinical samples. Preliminary support for an association with suicidality was also observed, with effects not readily explainable in terms of comorbid depression. There was strong evidence for an association between defeat and PTSD, although this may have been partly accounted for by comorbid depression. The findings for other anxiety disorders were less consistent. There was, however, evidence that social anxiety in individuals with psychosis may be related to perceptions of entrapment. Overall, there was evidence that perceptions of defeat and entrapment were closely associated with various forms of human psychopathology. These effects were often in the moderate to large range and superseded the impact of other environmental and psychological stressors on psychopathology. We provide a unified theoretical model of how defeat and entrapment may contribute to these different psychopathological conditions. Clinical implications and avenues for future research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A role of subicular and hippocampal afterdischarges in initiation of locomotor activity in rats

The anterior pituitary is known to be regulated by hypothalamic hormones via the portal system. However, our recent studies have demonstrated the presence of a substantial amount of substance P (SP)-, calcitonin gene-related peptide (CGRP)- and galanin (GAL)- immunoreactive (ir) nerve fibers with numerous varicosities in the anterior pituitaries of the Macaca mulatta monkey. The present study investigated the relationship of the GAL-ir nerve fibers to the glandular cells. The M. mulatta monkeys were used and sections of the anterior pituitary were double immunostained. GAL-ir nerve fibers and/or varicosities were found in proximity to contact directly with corticotropes, somatotropes, lactotropes, gonadotropes and thyrotropes without any exception. These findings indicate that a direct neural factor may be involved in the regulation of adenohypophyseal secretion.     

The attachment system in fledgling relationships: An activating role for attachment anxiety.

Is it sensible to study attachment dynamics between potential romantic partners before they share a full-fledged attachment bond? The present data indicate that such an approach may reveal novel insights about initial attraction processes. Four studies suggest that the state-like experience of attachment anxiety has functional implications within fledgling (i.e., desired or undeveloped) romantic relationships, well before the formation of an attachment bond. Studies 1 and 3 reveal that attachment anxiety directed toward a particular romantic interest is elevated before (in comparison with after) participants report being in an established relationship. Studies 2 and 3 demonstrate that such partner-specific attachment anxiety predicts attachment-relevant outcomes in fledgling relationships, including proximity seeking, safe haven, secure base, passionate love, and other approach behaviors. These associations were reliable above and beyond (and were typically as strong as or stronger than) the effect of sexual desire. Finally, Study 4 presents evidence that partner-specific attachment anxiety may cause several of these attachment-relevant outcomes. Attachment anxiety seems to be a normative experience and may signal the activation of the attachment system during the earliest stages of romantic relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive performance in rats differing in their inborn anxiety.

There is profound evidence that cognitive processes and anxiety are interrelated. To learn more about this interaction, the authors tested rats bred for either high (HABs) or low (LABs) anxiety-related behavior in a modified hole board task. This task allows parallel investigation of various cognitive processes and possibly related behavioral dimensions, both under baseline conditions and during cognitively stressful situations. The authors provide evidence that the degree of anxiety is differentially associated with enhanced performance for distinct informational processes in rats. As HABs and LABs did not differ in their anxiety-related behavior after habituation, that is, in a familiar environment during appetitive learning, the authors conclude that anxiety behavior in naive HABs may be due to differential cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of the medial prefrontal cortex in the play fighting of rats.

Although decorticated rats are able to engage in play, their play is abnormal in three ways. First, decorticates do not display the normal, age-related shifts in defensive strategies during development. Second, decorticates do not modify their defensive tactics in response to the social identity of their partners. Third, decorticates display a global shift in defensive tactics from more complex to less complex strategies. It has been shown that lesions of the motor cortex (MC) selectively produce the abnormal developmental effects on play, and that lesions of the orbitofrontal cortex (OFC) selectively produce the deficits in behavioral discrimination between social partners. In the current set of experiments, we demonstrate that lesions of the medial prefrontal cortex (mPFC) produce the shift from more complex to less complex defensive tactics, while leaving intact the age-related and partner-related modulation of defensive strategies. Thus, we have evidence for a triple dissociation of function between the MC, the OFC, and the mPFC with respect to social play behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in prefrontal cortical activity in working memory.

Working memory (WM) declines with advancing age. Brain imaging studies indicate that ventral prefrontal cortex (PFC) is active when information is retained in WM and that dorsal PFC is further activated for retention of large amounts of information. The authors examined the effect of aging on activation in specific PFC regions during WM performance. Six younger and 6 older adults performed a task in which, on each trial, they (a) encoded a 1- or 6-letter memory set, (b) maintained these letters over 5-s, and (c) determined whether or not a probe letter was part of the memory set. Comparisons of activation between the 1- and 6-letter conditions indicated age-equivalent ventral PFC activation. Younger adults showed greater dorsal PFC activation than older adults. Older adults showed greater rostral PFC activation than younger adults. Aging may affect dorsal PFC brain regions that are important for WM executive components. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of self-statements as a mediator in treatment for youth with anxiety disorders.

The authors investigated features of self-statements as predictors of anxiety in children with and without anxiety disorder (AD) and as a mediator of treatment of ADs in children. Children (N = 145) between the ages of 9 and 13 years participated (71 AD youth, 84 controls). Self-statements were classified by valence and content. Results indicated that children's anxious, but not positive or depressed, self-statements significantly predicted anxiety in children with and without AD. For children with AD, changes in anxious self-statements mediated treatment gains, replicating a previously reported finding. A states of mind ratio mediated only 1 outcome measure, and positive and depressive cognitions served no mediating role. The impact of anxious self-talk on children's adjustment and implications for cognitive theory of anxiety in children are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of performance anxiety in the development and maintenance of sexual dysfunction in men and women.

The current study evaluated the association between attitudes toward sex, stress, relationship quality, performance anxiety, and sexual dysfunction among 157 men (114 dysfunctional, 43 functional) and 186 women (84 dysfunctional, 102 functional). The results demonstrate that the main factors related to all types of sexual dysfunction among men were attitudes toward sex, conflict in their relationship, and performance anxiety. For women, the main factors related to all types of sexual dysfunction were attitudes toward sex, relationship quality, and performance anxiety. These results demonstrate the central role of performance anxiety in either the development or maintenance of sexual dysfunction among both men and women. Clearly, this is an area that has to be considered in any treatment program for sexual dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of frustration and anxiety on overt aggression.

A study of the frustration-aggression hypotheses. Ss were required to count backwards from 100 by 3. A high and low level of frustration situation was constructed, with the "high" being characterized by a threat of electric shock if E was dissatisfied with Ss performance, and E interrupting S by making sarcastic and insulting comments. Following this, E made predictions on what might be S's response on a questionnaire assessing attitudes towards driving, and S was allowed to administer shock to E when S felt E was in error. Measures of frequency and duration of shock and pressure exerted in depressing a shock plunger were obtained as well as GSR and answers to an anxiety questionnaire. The findings generally confirmed the frustration-aggression thesis. From Psyc Abstracts 36:04:4HK46H. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory bias for threatening information in anxiety and anxiety disorders: A meta-analytic review.

Although some theories suggest that anxious individuals selectively remember threatening stimuli, findings remain contradictory despite a considerable amount of research. A quantitative integration of 165 studies with 9,046 participants (clinical and nonclinical samples) examined whether a memory bias exists and which moderator variables influence its magnitude. Implicit memory bias was investigated in lexical decision/stimulus identification and word-stem completion paradigms; explicit memory bias was investigated in recognition and recall paradigms. Overall, effect sizes showed no significant impact of anxiety on implicit memory and recognition. Analyses indicated a memory bias for recall, whose magnitude depended on experimental study procedures like the encoding procedure or retention interval. Anxiety influenced recollection of previous experiences; anxious individuals favored threat-related information. Across all paradigms, clinical status was not significantly linked to effect sizes, indicating no qualitative difference in information processing between anxiety patients and high-anxious persons. The large discrepancy between study effects in recall and recognition indicates that future research is needed to identify moderator variables for avoidant and preferred remembering. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The assessment of anxiety by physiological behavioral measures.

There is little research to support the contention that clearly defined patterns of physiological-behavioral responses associated with anxiety arousal can be distinguished from other arousal patterns. Intercorrelations among physiological measures of anxiety obtained under either resting states or under stress are generally low. No studies have been reported in which several measures of behavior were obtained simultaneously with a variety of physiological measures under conditions likely to be fear arousing. From Psyc Abstracts 36:02:2HN34M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meta-analysis of the relations of anxiety sensitivity to the depressive and anxiety disorders.

There is a substantial literature relating the personality trait anxiety sensitivity (AS; tendency to fear anxiety-related sensations) and its lower order dimensions to the mood and anxiety (i.e., internalizing) disorders. However, particularly given the disorders’ high comorbidity rates, it remains unclear whether AS is broadly related to these disorders or if it shows a pattern of differential relations. Meta-analyses of the concurrent relations of AS with the internalizing disorders were conducted based on 117 studies and 792 effect sizes. Mean Anxiety Sensitivity Index scores by diagnostic group and AS–symptom correlations both indicated that AS is most strongly related to panic, generalized anxiety disorder (GAD), and posttraumatic stress disorder (PTSD). More specific analyses were also conducted on (a) AS correlations with symptom dimensions within individual disorders and (b) correlations between lower order AS components and symptoms. The meta-analytic correlation matrix for higher order AS–disorder relations was submitted to path analysis, modeling latent Distress disorders and Fear disorders that control for much of the shared variance among the disorders. Results of the path analysis indicated that AS is broadly related to these disorders but that agoraphobia, GAD, panic, and PTSD have the strongest associations. In addition, AS was more strongly related to the latent distress disorders than the fear disorders. Because of the contemporaneous assessment of AS and internalizing disorders in these studies, the results should not be taken to mean that AS has a stronger casual association with certain disorders. Implications for concurrent AS–internalizing relations, interpretations of the AS construct, and structural models of personality and psychopathology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of manifest anxiety and IQ on discrimination.

20 Ss were selected from a population of 400 high school students who had been given the Otis IQ test and the Taylor Scale of Manifest Anxiety so that five of them fell into each of the following groups: (a) high IQ, high anxiety, (b) high IQ low anxiety, (c) low IQ, low anxiety, and (d) low IQ, high anxiety. The Ss were asked to rate 10 attitudinal concepts on each of 10 scales. The results were tabulated to determine the frequency with which each S used each step in the scale. It was found that intelligence, as measured by the Otis IQ test, does significantly relate to scale discrimination. High IQ Ss made more use of the whole scale. High and low anxiety Ss make equally fine discriminations along a graduated series. However, IQ and anxiety do appear to interact with regard to discrimination. In general, the effect of increased anxiety on high IQ Ss is to make them less discriminating. The reverse effect is found for low IQ Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Depression and anxious apprehension distinguish frontocingulate cortical activity during top-down attentional control.

A network consisting of left dorsolateral prefrontal cortex (LDLPFC) and dorsal anterior cingulate cortex (dACC) has been implicated in top-down attentional control. Few studies have systematically investigated how this network is altered in psychopathology, despite evidence that depression and anxiety are associated with attentional control impairments. Functional MRI and dense-array event-related brain potential (ERP) data were collected in separate sessions from 100 participants during a color–word Stroop task. Functional MRI results guided ERP source modeling to characterize the time course of activity in LDLPFC (300–440 ms) and dACC (520–680 ms). At low levels of depression, LDLPFC activity was indirectly related to Stroop interference and only via dACC activity. In contrast, at high levels of depression, dACC did not play an intervening role, and increased LDLPFC activity was directly related to decreased Stroop interference. Specific to high levels of anxious apprehension, higher dACC activity was related to more Stroop interference. Results indicate that depression and anxious apprehension modulate temporally and functionally distinct aspects of the frontocingulate network involved in top-down attention control. (PsycINFO Database Record (c) 2011 APA, all rights reserved)