scholarly journals The ability of an extinguished CS and a CS given conditioned inhibition training to pass tests for inhibition

2019 ◽  
Author(s):  
◽  
Rachel Anne Richardson

Conditioned inhibition (CI) is a classical conditioning procedure that results in a conditioned stimulus (CS) that predicts the absence of an unconditioned stimulus (US). A procedure known as Pavlovian conditioned inhibition training is the most common procedure for producing CI. In this procedure, a nontarget CS (CS A) is paired with the US and then CS A is presented with the target CS (CS X) without the US. Therefore, AUS trials and AX-noUS trials are given. CS X acquires inhibitory properties during these AX trials. Research has shown that extinction also produces CI. Extinction occurs when a CS (CS X) is paired with the US during conditioning and then this CS is presented alone without the US. The Rescorla-Wagner model predicts that the two CSs during AX-noUS trials will compete for learning and this should lead to slow and limited learning about those cues (a loss of excitation for CS A and inhibition acquired for CS X) due to this competition. During extinction trials, CS X does not compete for learning, so the subject should learn rapidly about the CS. The following experiments found that extinction produced less inhibition than Pavlovian conditioned inhibition training.

Author(s):  
Kathrin I. Thiede ◽  
Jan Born ◽  
Albrecht P. A. Vorster

Sleep is essential for memory consolidation after learning as shown in mammals and invertebrates such as bees and flies. Aplysia californica displays sleep and sleep in this mollusk was also found to support memory for an operant conditioning task. Here, we investigated whether sleep in Aplysia is also required for memory consolidation in a simpler type of learning, i.e., the conditioning of the siphon withdrawal reflex. Two groups of animals (Wake, Sleep, each n=11) were conditioned on the siphon withdrawal reflex with the training following a classical conditioning procedure where an electrical tail shock served as unconditioned stimulus (US) and a tactile stimulus to the siphon as conditioned stimulus (CS). Responses to the CS were tested before (Pre-test), 24 and 48 hours after training. While Wake animals remained awake for 6 hours after training, Sleep animals had undisturbed sleep. The 24h-test in both groups was combined with extinction training, i.e., the extended presentation of the CS alone over two blocks. At the 24h-test, siphon withdrawal durations to the CS were distinctly enhanced in both Sleep and Wake groups with no significant difference between groups, consistent with the view that consolidation of a simple conditioned reflex response does not require post-training sleep. Surprisingly, extinction training did not reverse the enhancement of responses to the CS. On the contrary, at the 48h-test, withdrawal durations to the CS were even further enhanced across both groups. This suggests that processes of sensitization, an even simpler non-associative type of learning, contributed to the withdrawal responses. Our study provides evidence for the hypothesis that sleep preferentially benefits consolidation of more complex learning paradigms than conditioning of simple reflexes.


2020 ◽  
Vol 71 ◽  
pp. 101642
Author(s):  
Rachel A. Richardson ◽  
Paige N. Michener ◽  
Courtney L. Gann ◽  
Isabella M. North ◽  
Todd R. Schachtman

2002 ◽  
Vol 55 (1) ◽  
pp. 173-193 ◽  
Author(s):  
Annette Kinder ◽  
Harald Lachnit

Two experiments are reported, which employed a Pavlovian eyelid conditioning procedure with human participants. The experiments tested the predictions of three models of the time-course of processing under time pressure. These were the extended generalized context model (Lamberts, 1998), and two variants of the Rescorla-Wagner model (Rescorla & Wagner, 1972), which were activated in cascade mode. Reinforcement schedules in the experiments were equivalent either to an AND rule or to an XOR rule. The time available for processing the conditioned stimulus and initiating a conditioned response was manipulated by varying the interval from the onset of the conditioned stimulus to the onset of the unconditioned stimulus. The results were in accord with the predictions of one of the two variants of the Rescorla-Wagner model.


Author(s):  
M.A. Gregory ◽  
G.P. Hadley

The insertion of implanted venous access systems for children undergoing prolonged courses of chemotherapy has become a common procedure in pediatric surgical oncology. While not permanently implanted, the devices are expected to remain functional until cure of the primary disease is assured. Despite careful patient selection and standardised insertion and access techniques, some devices fail. The most commonly encountered problems are colonisation of the device with bacteria and catheter occlusion. Both of these difficulties relate to the development of a biofilm within the port and catheter. The morphology and evolution of biofilms in indwelling vascular catheters is the subject of ongoing investigation. To date, however, such investigations have been confined to the examination of fragments of biofilm scraped or sonicated from sections of catheter. This report describes a novel method for the extraction of intact biofilms from indwelling catheters.15 children with Wilm’s tumour and who had received venous implants were studied. Catheters were removed because of infection (n=6) or electively at the end of chemotherapy.


2020 ◽  
Vol 18 (1/2020) ◽  
pp. 33-67
Author(s):  
Olga Stevanovic

The subject of this paper encompasses US policy towards Poland and the Baltic States regarding energy security during Donald Trump’s presidency. It is discernible that vast domestic energy resources have created an opportunity for the US to project more power to these countries, and the surrounding region. We argue that Trump and his administration’s perceptions have served as an intervening variable in that opportunity assessment, in accordance with the neoclassical realist theory. The main research question addressed in this paper is whether US has used that opportunity to contribute to energy security in countries it has traditionally deemed as allies. Two aspects of US approach to energy security of the designated countries are taken into consideration: liquified natural gas exports and support for the Three Seas Initiative. The way Trump presented his policy and its results in his public statements has also been considered in this paper. The article will proceed as follows. The first subsection of the paper represents a summary of energy security challenges in Poland and the Baltic States. The second subsection is dedicated to the opportunity for the US to project energy power and to Trump’s perceptions relevant for the opportunity assessment. The third subsection deals with American LNG exports to these countries as a possible way for contributing to energy security in Poland and the Baltic States. The last part of the paper addresses the Three Seas Initiative and US approach to this platform.


2017 ◽  
Vol 12 (1) ◽  
pp. 39-57
Author(s):  
Jamie McKeown

This article reports the findings from a study of discursive representations of the future role of technology in the work of the US National Intelligence Council (NIC). Specifically, it investigates the interplay of ‘techno-optimism’ (a form of ideological bias) and propositional certainty in the NIC’s ‘Future Global Trends Reports’. In doing so, it answers the following questions: To what extent was techno-optimism present in the discourse? What level of propositional certainty was expressed in the discourse? How did the discourse deal with the inherent uncertainty of the future? Overall, the discourse was pronouncedly techno-optimist in its stance towards the future role of technology: high-technological solutions were portrayed as solving a host of problems, despite the readily available presence of low-technology or no-technology solutions. In all, 75.1% of the representations were presented as future categorical certainties, meaning the future was predominantly presented as a known and closed inevitability. The discourse dealt with the inherent uncertainty of the subject matter, that is, the future, by projecting the past and present into the future. This was particularly the case in relation to the idea of technological military dominance as a guarantee of global peace, and the role of technology as an inevitable force free from societal censorship.


2021 ◽  
Vol 5 (1) ◽  
pp. 4-21

Received 30 January 2021. Accepted for publication 20 March 2021 The Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction (BTWC) does not have a legally binding verification regime. An attempt by the Ad Hoc Group of Experts, created by the UN Committee on Disarmament, to strengthen the BTWC by developing a legally binding document – the Protocol, was blocked by the United States in July 2001. The purpose of this work is to study the history, main provisions, significance and reasons for not signing the Protocol to the BTWC. The attention is paid to the events in biological weapons control, which have led a number of countries to the understanding of the necessity to develop the Protocol. The background of the US actions to block this document is the subject of special consideration. During the Second Review Conference on the Implementation of the Convention (8–25 September 1986, Geneva) the USSR, the German Democratic Republic and the Hungarian People's Republic proposed to develop and adopt the Protocol as an addition to the BTWC. This document was supposed to establish general provisions, definitions of terms, lists of agents and toxins, lists of equipment that was present or used at production facilities, threshold quantities of biological agents designed to assess means and methods of protection. The proposed verification mechanism was based on three «pillars»: initial declarations with the basic information about the capabilities of each State Party; inspections to assess the reliability of the declarations; investigations to verify and confirm or not confirm the alleged non-compliance with the Convention. The verification regime was to be under the control of an international organization – the Organization for the Prohibition of Bacteriological (Biological) and Toxin Weapons. However, the US military and pharmaceutical companies opposed the idea of international inspections. The then US Undersecretary of State for Arms Control and International Security, John Robert Bolton II, played a special role in blocking the Protocol. During the Fifth Review Conference in December 2001, he demanded the termination of the Ad Hoc Group of Experts mandate for negotiations under the pretext that any international agreement would constrain US actions. The current situation with biological weapons control should not be left to chance. Measures to strengthen the BTWC should be developed, taking into account the new fundamental changes in dual-use biotechnology. It should be borne in mind, that the Protocol, developed in the 1990s, is outdated nowadays.


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