Concordia University

About: Concordia University is a education organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Context (language use) & Control theory. The organization has 13565 authors who have published 31084 publications receiving 783525 citations. The organization is also known as: Sir George Williams University & Loyola College, Montreal.

Rewarding Actions of Phencyclidine and Related Drugs in Nucleus Accumbens Shell and Frontal Cortex

Abstract: Rats learned to lever-press when such behavior was reinforced by microinjections of phencyclidine (PCP) directly into the ventromedial (shell) region of nucleus accumbens, indicating that the drug has direct rewarding actions in that region. Separate groups of rats learned to lever-press when reinforced with microinjections of dizocilpine (MK-801) or 3-((±)2-carboxypiperazin-4yl)propyl-1-phosphate (CPP), drugs known to block NMDA receptor function but not dopamine uptake, into the same region. Each drug was ineffective or markedly less effective when injected at a slightly more dorsal and lateral site in the core of nucleus accumbens. Self-administration of PCP, MK-801, or CPP directly into nucleus accumbens was not altered by co-infusion of a dose of the dopamine antagonist sulpiride that effectively blocked intracranial self-administration of the dopamine uptake inhibitor nomifensine, suggesting that the rewarding actions of the NMDA receptor antagonists are not dopamine-dependent. Rats also developed lever-pressing habits when PCP, MK-801, and CPP were each microinjected directly into frontal cortex, a region previously associated with the rewarding actions of cocaine but not nomifensine. Thus nucleus accumbens and frontal cortex are each potential substrates for the rewarding properties of PCP and related drugs, and the ability of these drugs to disrupt NMDA receptor function seems sufficient to account for their rewarding actions. When considered with independent evidence, the present results suggest a model of drug reward within which the critical event is inhibition of medium spiny neurons in nucleus accumbens.

E-Commerce and Web Technologies

Abstract: Existing electronic negotiation systems (ENSs) typically implement a single, fixed negotiation protocol, which restricts their use to negotiation problems that were anticipated and established a priori by the system designers. The single-protocol restriction limits ENSs’ applicability in experiments and in many real-life negotiation situations. ENSs that allow for the use of different protocols also allow for the customization to users’ needs and abilities. We present theoretical foundations for the design of flexible and highly customizable protocol-driven ENSs. Our design enables researchers and negotiators to map negotiation activities onto system components and to construct their own negotiation protocols by creating a sequence of layout programs invoking components and rules. * This work was supported with grants from the Initiative for New Economy of the Social Sciences and Humanities Research Council Canada, and the Natural Science and Engineering Research Council Canada. e-negotiations 2004 2