Conditioned stimuli

Mechanism through which repeated associations between two stimuli induce a new learned response. In particular, by pairing a neutral stimulus (conditioned stimulus) with an unconditioned stimulus (that induces a physiological response) many times, the neutral stimulus alone will be capable of producing a conditioned physiological response. 

Unless one identifies internal inhibition with reversible agglomeration of proteins, it is difficult to see what one can do with Pavlov s theory of sleep.10 Sleep and what we call internal inhibition are one and the same process. The fundamental condition of the appearance and development of internal inhibition and sleep is exactly the same. It consists in the more or less prolonged or many times repeated isolated action of a conditioned stimulus producing stimulation of the cellular structures in the cortex. In all cases of internal inhibition which were discussed in the fourth to the seventh lectures drowsiness and sleep were met with continually. In the case of extinction of a conditioned reflex some animals even at the first extinction showed not only a disappearance of the conditioned secretory and corresponding motor reaction but also a great dullness as compared with the normal state of the animal before the extinction. Repetition of extinctions, in the course of a number of days, even if all the conditioned stimuli were reinforced in between, led in every case to an obvious drowsiness and even sleep of the animal in its stand, though no such symptoms had ever previously been observed. 

Perez, L. and Lysle, D.T., Corticotropin-releasing hormone is involved in conditioned stimulus-induced reduction of natural killer cell activity but not in conditioned alterations in cytokine production or proliferation responses, J. Neuroimmunol., 63, 1, 1995. 

Schwarz, K.S. and Cunningham, C.L., Conditioned stimulus control of morphine hyperther-... 

Fig. 29.2 A. Proportion of pups responding by searching movements to neutral odorant E and F, 24h after being exposed to the MP-odorant E mixture (MP-E) or to odorant E alone (E). B. Proportion of pups displaying searching to an odorant MP-leamed (dotted bar) as compared to the MP (black bar). C. Schematic of the reinforcing function of MP (US, CS and UR unconditioned stimulus, conditioned stimulus and unconditioned response, respectively) (adapted from Coureaud et al. 2006c)...

F%. 1 (a) Dose-response curve from rats trained to discriminate between 0.2 mg kg of nicotine and saline. Data are from 13 rats, each tested at least three times at each dose, (b) Block of nicotine (0.2 mg kg ) discrimination by the centrally active nicotinic antagonist mecamylamine (0.25 mg kg ) but not by chlorisondamine at a 0.025 mg kg dose that blocks peripheral nicotinic choUnoceptors but does not penetrate into the CNS (Sal, Saline Nic, Nicotine Csd, Chlorisondamine Mec, Mecamylamine). Chlorisondamine blocks nicotine discrimination when injected intra-cerebroventricularly (Kumar et al. 1987, data not shown). Data shown are for the number of sessions that began with selection of the nicotine-appropriate lever expressed as a percentage of the total number of sessions. Redrawn with permission from Tables 1 and 2 in Morrison CF, Stephenson JA. Nicotine injections as the conditioned stimulus in discrimination learning (1969), Copyright Springer... 

Miyata H, Ando K, Yanagita T (2002) Brain regions mediating the discriminative stimulus effects of nicotine in rats. Ann N Y Acad Sci 965 354-363 Morrison CF, Stephenson JA (1969) Nicotine injections as the conditioned stimulus in discrimination learning. Psychopharmacologia 15 351-360... 

Moita MA, Rosis S, Zhou Y, LeDoux JE, Blair HT (2003) Hippocampal place cells acquire location-specific responses to the conditioned stimulus during auditory fear conditioning. Neuron 37 485-497... 

Referred to as a conditioned fear paradigm, the fear potentiated startle response was first described by Brown et al. (1951). In the original test, an acoustic stimulus is presented in the presence of a conditioned stimulus that has previously been paired with an aversive, unconditioned stimulus. The amplitude of the acoustic startle response is thought to indicate the degree of conditioned anxiety, which can be reduced by anxiolytic drugs (Davis et al. 1993 Hijzen et al. 1995). 

In classical Pavlovian fear conditioning, an initially neutral cue (conditioned stimulus, CS), through temporal pairing with an aversive unconditioned stimulus (US), acquires the abihty to ehcit a fear response in the absence of the US. This acquired abihty represents a type of associative learning and imphes that plasticity mechanisms underlying fear learning may be similar to those... 

Campeau S, Miserendino MJD, Davis M (1992) Intra-amygdala infusion of the N-methyl-D-asparate receptor antagonist AP5 blocks acquisition but not expression of fear-potentiated startle to an auditory conditioned stimulus. Behav Neurosci 106 569-574 Caton P, Tousman SA, Quock RM (1994) Involvement of nitric oxide in nitrous oxide anxiolysis in the elevated plus-maze. Pharmacol Biochem Behav 48 689-692 Chapman P, Kairiss EW, Keenan CL, Brown TH (1990) Long-term synaptic potentiation in the amygdala. Synapse 6 271-278... 

In a fear-conditioning experiment, a neutral stimulus, such as a tone or a light, is paired with an aversive stimulus, such as a shock, a loud noise, or an aversive air blast. Following this experience, the formerly neutral stimulus becomes a conditioned stimulus (CS-F) and acquires the ability to elicit behaviors and physiological responses formerly only associated with the aversive stimulus, the unconditioned stimulus (UCS). Enthusiasm for this work derives at least partly from the precise delineation of neural circuits, down to the level of the genome, engaged by environmental components that produce fear conditioning (LeDoux,... 

Conditioning. A Pavlovian explanation of placebo effects has been based on the traditional model of classical conditioning active ingredients serve as unconditional stimuli and the vehicles in which they are delivered (pills, injections), particularly the elements of therapeutic procedures, function as conditional stimuli. After repeated pairing of unconditioned and conditioned stimuli, the conditional stimulus elicits a conditional response even if the conditioned stimulus (e.g. the pill) is presented alone (without active ingredient). 

Notes A conditioned stimulus for appetite at the arrow increases the value of the smaller, earlier reward until it is temporarily preferred but anticipation of this change would not lead to avoidance, but rather make the figure approach figure 7,1. 

The categories of methods used in behavioral toxicology fall into two principal classes, stimulus-oriented behavior, and internally generated behavior. The former includes two types of conditioned behavior operant conditioning, in which animals are trained to perform a task in order to obtain a reward or to avoid a punishment, and classical conditioning, in which an animal learns to associate a conditioning stimulus with a reflex action. Stimulus-oriented behavior also involves unconditioned responses in which the animal s response to a particular stimulus is recorded. 

Conditioned stimulus e.g., a light, paired with a footshock, Table 18.1. Startle stimulus, such as an air puff or loud noise (1, 7, 18). 

The startle response test pairs a conditioned stimulus (sound, light) with a footshock to induce an anxiogenic startle response in mice. While the sensitivity of this test to many drugs is yet to be established, benzodiazepine and serotonergic anxiolytics have been effective in reducing the startle response (1). Since this model seems to be unaffected by motor phenotypes, activity levels, or neurological deficits, this test (unlike many other anxiety models discussed here) allows researchers to study mouse anxiety without these confounding factors (see Note 17). 

In a conditioning trial, a conditioned stimulus (usually a light e.g., 15 W) is paired with a footshock. The timing of the conditioned stimulus and footshock can be controlled by the data acquisition software for consistency (7). 

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