Amnestic effect of intrahippocampal AM251, a CB1-selective blocker, in the inhibitory avoidance, but not in the open field habituation task, in rats

CB1 is the most abundant metabotropic receptor of the brain, being found in areas classically involved in learning and memory and present at higher density at presynaptic terminals. Different sets of evidence support the idea that endogenous ligands (endocannabinoids) to the CB1 receptors act as modulators of neurotransmission. In hippocampus, endocannabinoids seem to act as retrograde messengers mediating down-regulation of GABA release. Previous reports have described a cognitive impairment effect of cannabinoid agonists, or facilitation by antagonists. The scope of the present study is to investigate the effect of intrahippocampal administration of the CB1-selective antagonist, AM251, in two behavioral tasks. One hundred and twelve male Wistar rats with bilateral cannulae implanted in the CA1 region of the dorsal hippocampus were trained in a step-down inhibitory avoidance task (IA, footshock, 0.5 mA) or an open field habituation task (OF). Immediately, after training, animals received an infusion of 0.55, 5.5, and 55.5 ng/side of AM251 (Tocris), or its vehicle (DMSO/saline), via these cannulae. Our results show that AM251 disrupted memory consolidation of the IA task, but not the OF task, an effect that seems to be purely mnemonic since the drug showed no motor performance effects. Only the intermediate dose (5.5 ng/side) of AM251 was effective in IA and the absence of effect with the larger dose may be the consequence of non-specific binding. The fact that OF was not affected raises the possibility that this endogenous system requires some degree of aversiveness to be recruited. We propose that increased levels of endogenous cannabinoids in the hippocampus, following a training session, contribute to facilitate memory consolidation, a process that may have been disrupted with AM251.     

Suárez and the doctrine of the transcendentals

This article discusses Suárez's views concerning the transcendentals, that is, being and those attributes of it that extend to everything. In particular it explores Suárez's notion of transcendentality and the way in which he conceived the transcendental attributes of being are related to it. It makes two claims: First, that Suárez has an intensional, rather than an extensional understanding of transcendentality; and, second, that Suárez's understanding of truth and goodness, as expressing real extrinsic denominations based on real relations, appears to contain an inconsistency.I am grateful to Jane Bristol, John Doyle, and Scott MacDonald for their comments on an early draft of this paper.     

Concurrent measurement of heart rate and instrumental avoidance behavior in the Rhesus monkey

A graphical method has been developed for the concurrent recording of heart beats and lever responses during behavioral experiments. The EKG signal fed into any DC amplifier goes to a fixed level trigger circuit and relay driver with its own power supply. The signal from this drives any standard cumulative recorder. Lever response rates are recorded concurrently on an additional cumulative recorder using the same paper speed.     

Ideology,modernization and politico-economic development in Latin America

The authors state that social and political processes are continuously interrelated and modify each other in a circular fashion. The economic variable seems to be the most independent and strategic one in the complex and circular causal process of contemporary history. Its importance is due to the fact that economic forces have become the means that contribute the most to the attainment of varied social and political goals. holding appointments in the Department of International Relations, Economics, Political Science and Sociology/Anthropology. He is also a Senior Research Scholar at the University of Miami’s Graduate School of International Studies. He has been a Senior Fellow at Brookings Institution and is presently a staff member there. He has published more than thirty books and over one hundred articles.     

Crossing the Threshold: The Spillover of Community Racial Diversity and Diversity Climate to the Workplace

We examined the spillover of community diversity to the workplace using a sample of 2,045 professionals living in communities across the U.S. Spillover effects were examined using 2 measures of community diversity: the degree to which employees were racially or ethnically similar to others in their community and perceptions of their community's diversity climate. Aligned with theories of group threat and racial segregation, Whites who were racially dissimilar to their communities expressed stronger intentions to leave their communities, and ultimately their workplaces, than those living in primarily White communities. However, community diversity climate offset these relationships; Whites who lived in communities that were racially dissimilar to them, but experienced the climate as inclusive, had lower moving intentions than those in communities that were experienced as racially intolerant. In contrast, for people of color, community diversity climate, rather than racial similarity to the community, predicted moving intentions. For both groups, the diversity climate in the community predicted moving intentions, which in turn predicted work turnover intentions, job search behaviors, and physical symptoms of stress at work. These findings suggest that the intention to leave one's community, and ultimately one's workplace, is influenced by community experiences and the community's perceived diversity climate.     

Assessing the five factors of personality in adolescents: the junior version of the Spanish NEO-PI-R

This article presents the development of a junior version of the Spanish (Castilian) NEO Personality Inventory-Revised (JS NEO) suitable for adolescents aged 12 to 18 years. The psychometric properties of the new JS NEO were investigated using two samples of 2,733 and 983 adolescents in Spain. The results showed that the adult NEO-PI-R factor structure was replicated with the junior version of the inventory and that the reliabilities of the scales were adequate. The cross-form correlations between the junior and the adult versions of the questionnaires indicated good equivalence indices. Furthermore, a joint factor analysis of the JS NEO and the Big Five Questionnaire-Children (BFQ-C) provided additional evidence for the construct validity of the JS NEO.     

Microswitch technology and contingent stimulation to promote adaptive engagement in persons with minimally conscious state: a case evaluation

This study assessed whether a post-coma woman functioning at the lower end of the minimally conscious state would (a) develop adaptive responding through the use of microswitch technology and contingent stimulation, (b) consolidate and maintain her responding over time, and (c) show evidence of response-consequences awareness (learning and discrimination). The study involved an ABABB¹CB¹ sequence in which the A represented baseline phases, the B and B¹ intervention phases, and the C a control phase with continuous stimulation. Results indicated that the woman developed adaptive responding and consolidated it over the intervention phases of the study. The woman also showed evidence of being aware of response-consequences links. Potential implications and limitations of these findings are discussed.     

Ileal inducible nitric oxide synthase mRNA expression in response to stress is modified in Sprague-Dawley rats exposed to a previous intestinal inflammation

The ability of stress to initiate or reactivate an inflammatory process seems to depend on an individual's susceptibility to stressful stimuli. The aim of this study was to establish whether previous inflammation alters the response to stress in Sprague-Dawley rats, a strain not especially susceptible to stressful stimuli. Stress exposure was performed in rats treated with indomethacin, to induce cyclic intestinal inflammation, during the inactive phase of inflammation. Both control and indomethacin-treated rats submitted to stress showed a decrease in body weight gain and blood leukocyte levels, as well as an increase in fecal pellet output. The increase in intestinal mucosal mast cell count induced by stress was similar in both groups of animals. Moreover, no differences were observed between control and indomethacin-treated rats in the degree of bacterial translocation and myeloperoxidase levels after stress exposure. Despite these similarities, differences between groups were observed in inducible nitric oxide synthase (iNOS) mRNA expression. Although ileal iNOS mRNA expression was inhibited in healthy rats submitted to stress, stress failed to modify this parameter in indomethacin-treated rats. As iNOS is another inflammatory marker, our results may allow the possibility that a previous intestinal inflammation could change the intestinal susceptibility to stress. Whether these differences in ileal iNOS expression can be indicative of a possible change in the predisposition to develop an intestinal inflammatory reaction in response to stress in Sprague-Dawley rats remains to be elucidated.     

Grasping with the eyes: The role of elongation in visual recognition of manipulable objects

Processing within the dorsal visual stream subserves object-directed action, whereas visual object recognition is mediated by the ventral visual stream. Recent findings suggest that the computations performed by the dorsal stream can nevertheless influence object recognition. Little is known, however, about the type of dorsal stream information that is available to assist in object recognition. Here, we present a series of experiments that explored different psychophysical manipulations known to bias the processing of a stimulus toward the dorsal visual stream in order to isolate its contribution to object recognition. We show that elongated-shaped stimuli, regardless of their semantic category and familiarity, when processed by the dorsal stream, elicit visuomotor grasp-related information that affects how we categorize manipulable objects. Elongated stimuli may reduce ambiguity during grasp preparation by providing a coarse cue to hand shaping and orientation that is sufficient to support action planning. We propose that this dorsal-stream-based analysis of elongation along a principal axis is the basis for how the dorsal visual object processing stream can affect categorization of manipulable objects.