Microdialysis administration of vasopressin and vasopressin antagonists into the septum during pole-jumping behavior in rats.

Wistar rats (n = 95) were trained in a pole-jumping apparatus (10 trials/session/day) to investigate the involvement of centrally and peripherally released endogenous AVP in their acquisition rate and to examine the feasibility of the microdialysis technique for the administration of peptides during a behavioral test. After session 1, a microdialysis probe was implanted into the septum; during sessions 2 and 3 the probe was perfused with artificial cerebrospinal fluid (aCSF) alone or containing either AVP (delivered amount via the probe: 0.2 ng) or the V1 (d(CH2)5Tyr(Me)AVP, 5.0 ng) or the V2/V1 (d(CH2)5-D-Tyr(Et)VAVP, 5.0 ng) antagonist. Administration of AVP via microdialysis into the septum failed to alter the acquisition rate of pole jumping. Also, ip application of both hypertonic saline and the AVP V1 antagonist (10 micrograms) in another experiment failed to show a significant effect upon behavior. Septal administration of the V1 or the V2/V1 antagonist via microdialysis, however, produced a significantly impaired performance. The results indicate that AVP release within the septum is involved in the acquisition of pole-jumping behavior probably mediated by the V1 receptor subtype. An additional involvement of the V2 receptor subtype, however, cannot be entirely excluded. The microdialysis technique proved to be a potent tool to administer substances concomitantly with behavioral tests.     

Histories of sexual abuse in adolescent male runaways

In this study, data on sexual victimization in the histories of 89 Canadian male runaways as well as information on physical victimization, family structure, family financial stability, delinquent and criminal activities, and reasons for running away from home were evaluated. The population of male runaways evidenced dramatically higher rates of sexual and physical abuse than did randomly sampled populations. Sexually abused and nonsexually abused male runaways shared characteristics noted in the literature as common to runaways: problem families, high rates of delinquency, depression, tension, low self-image, and history of physical abuse. Sexually abused male runaways differed from nonsexually abused runaways in their reactions to their runaway event, with sexually abused male runaways responding in highly avoidant patterns coupled with extreme withdrawal from all types of interpersonal relationships. These differences are explained as consistent with known sequelae of sexual abuse, and the implications for treatment by runaway shelters and for further research are suggested.     

Intra- and interindividual relationships between elation-depression and desire for excitement

This study examined the relationship between elation-depression and desire for excitement on both intra- and interindividual levels. It was hypothesized that there would be a positive linear relationship between elation and desire for tranquillity These intraindividual hypotheses received strong support. This support would suggest that radical incongruities between activity demands and mood preparedness are often painful and would imply that in order for mood alteration to be successful it must take place gradually It was also hypothesized that characteristic level of elation-depression would be positively related to mean ratings of desire for excitement, positively related to score on a desire for excitement test, and negatively related to mean ratings of desire for tranquillity These interindividual hypotheses were not supported. Although it is probably most reasonable to accept the lack of correspondence between intra- and interindividual results, the operation of social comparison effects and social desirability bias may have obscured the predicted interindividual relationships     

Disrupted memory inhibition in dementia of Alzheimer’s type

Cognitive inhibition has been suggested to deteriorate in Alzheimer’s disease. While numerous studies with different experimental paradigms found evidence on impaired inhibition in attention and memory, evidence in favour of intact memory inhibition has been reported with regard to the phenomenon of retrieval-induced forgetting (Moulin et al., 2002). Here, we adapted the previously used paradigm in order to reduce the contribution of non-inhibitory processes and examined whether retrieval-induced forgetting could still be observed in a sample of participants with diagnosed Alzheimer’s disease. In contrast to the previous finding, we found that retrieval-induced forgetting only occurred in an age-matched control group. These results suggest that inhibitory deficits in Alzheimer’s disease also generalize to memory inhibition that resolves interference occurring during retrieval, whereas effects of retrieval-induced forgetting may still occur when non-inhibitory causes, such as, blocking by previously retrieved content, are not precluded.     

Stimulus-driven and goal-driven control over visual selection

This article explored the extent to which stimulus-driven control over visual selection is modulated by goal-driven factors. Observers searched for a no-onset color target among 3 distractors and signaled its location either manually or with a saccade. Additional distractors appeared either with or without an abrupt onset and were either similar or dissimilar to the target. Abrupt onsets disrupted saccades to the target, especially when they shared the target color. Irrelevant onsets also interfered with the manual responses, but this interference was dependent on the particular type of manual response. Stimulus-driven and contingent capture can occur within a single paradigm, but the extent and nature of these effects depend on the specific response required.     

Sexual predator commitment laws: lessons for law and the behavioral sciences

Sex offender commitment laws use a mental health commitment model to lock up the "most dangerous" sex offenders after their prison sentences expire. In Kansas v. Hendricks, the United States Supreme Court rejected the major constitutional challenges to these laws. The Hendricks case clarifies important ambiguities about the use of civil commitment to enforce "police power" interests, as opposed to "parens patriae" interests. Hendricks also clarifies the role of "treatment" in justifying civil commitment. While there remain some important legal issues to be resolved, the future direction of sex offender commitment schemes will turn most significantly on policy decisions. The behavioral sciences can play an important role in shaping these decisions. The most significant questions concern whether expensive commitment programs are the most effective use of scarce treatment and supervision dollars. Additional research should be directed to improving dynamic predictors of recidivism, operationalizing "inability to control" standards, judging the "social meaning" of commitment laws, and assessing the potential treatment disincentives of these laws.     

Colour matching of isoluminant samples and backgrounds: a dimming effect

Sequential asymmetrical colour matching of forty Munsell samples simulated under illuminant C and one of eight test illuminants was carried out. The subjects matched the appearance of each sample under illuminant C with its appearance under the test illuminant. Samples and background (N7) were presented for 1 s under the test illuminant and were isoluminant with each other. Subjects adjusted hue, chroma, and value under illuminant C. The experiments distinguished two groups of subjects; some observers needed to reduce the luminance of the sample to make a match while others did not. This 'dimming' occurred when the matches were close to cardinal axes, especially the tritanopic confusion line. A model of luminance and cone-opponent mechanisms contributing to brightness can account for the dimming effect. Details of analysis in cone-opponent space (L - M, L + M - S, L + M) are presented in the companion paper (Stanikunas et al, 2005 Perception 34 this issue).     

The activity of the hypothalamo-neurohypophysial system in response to acute stressor exposure: neuroendocrine and electrophysiological observations

The present mini review focuses on stress-induced alterations of the electrical and secretory activity of vasopressin (AVP) and oxytocin (OXT) neurones originating within the supraoptic nucleus (SON) and constituting the hypothalamo-neurohypophysial system (HNS) in the male rat. Previously, it was thought that SON neurones are predominantly activated by osmotic and reproductive stimuli. However, recent findings also suggest a selective activation of AVP and/or OXT neurones in response to specific stressors. Inhibitory amino acids seem to participate at the level of the SON in the control of HNS activity during stress. Taurine, probably of glial origin, selectively inhibits the secretory activity of AVP neurones. In contrast, GABA, probably of neuronal origin, interferes with the release of OXT both from axon terminals into blood and from somata/dendrites into the extracellular fluid of the SON. Depending upon whether a defined stressor triggers taurine and/or GABA release within the SON the secretion of AVP and/or OXT from HNS neurones will be inhibited. These observations shed new light on the neurone-neurone and glial-neurone interactions that ensure an appropriate neuroendocrine stress response.     

Object permanence in common marmosets (Callithrix jacchus)

A series of 9 search tasks corresponding to the Piagetian Stages 3-6 of object permanence were administered to 11 common marmosets (Callithrix jacchus). Success rates varied strongly among tasks and marmosets, but the performances of most subjects were above chance level on the majority of tasks of visible and invisible displacements. Although up to 24 trials were administered in the tests, subjects did not improve their performance across trials. Errors were due to preferences for specific locations or boxes, simple search strategies, and attentional deficits. The performances of at least 2 subjects that achieved very high scores up to the successive invisible displacement task suggest that this species is able to represent the existence and the movements of unperceived objects.