Appetitive stimuli

Drug addiction might be just a special case of abnormal motivation secondary to nonadaptive responsiveness of NAc shell DA to primary appetitive stimuli. Thus, other disturbances of motivated behavior characterized by compulsion and excessive reactivity... 

Bassareo V, Di Chiara G (1999b) Modulation of feeding-induced activation of mesolimbic dopamine transmission by appetitive stimuli and its relation to motivational state. Eur J Neurosi 77 4389-4397. Bassareo V, Tanda G, Di Chiara G (1995) Increase of extracellular dopamine in the medial prefrontal cortex during spontaneous and naloxone-precipitated opiate abstinence. Psychopharmacology 722 202-205. 

These observations are consistent with the prediction that sensitization induced by repeated drug exposure increases the basic responsiveness of DA neurons to stimuli (Robinson and Berridge, 1993). However, this conclusion, while consistent with the prediction of the theory, turns out to be deleterious for its validity as a model of human addiction. In fact, since sensitization increases the incentive properties of any appetitive stimulus, not only of drug-related ones, it can hardly account for a cardinal feature of drug addiction, namely that the excessive impact over behavior exerted by drug-conditioned stimuli is reciprocated by a reduced impact by stimuli conditioned to nondrug rewards. 

Datla KP, Ahier RG, Young AM, Gray JA, Joseph MH (2002) Conditioned appetitive stimulus increases extracellular dopamine in the nucleus accumbens of the rat. Eur J Neurosci 76 (10) 1987—1993. 

The Lorenz-Craig model Appetitive behavior - releasing stimulus situation - consummatory act was later modified by N. Tinbergens hierarchy model of appetite behaviors (for details see I. Eibl-Eibesfeldt 1975, 1987). 

Thus the problem is not the nonexistence of classical conditioning, either in the laboratory or in creating ordinary appetites. On the contrary, conditioning is a familiar phenomenon. The problem is that conditioning per se connects only information—one stimulus to another—and does not transfer responses. Responses certainly arise to conditioned stimuli, and these responses often closely resemble the responses elicited by unconditioned stimuli, but the evidence is that they occur only insofar as they are motivated. 

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. 

Novelty being a prerequisite for the stimulation of DA release in the NAc shell but not for behavioral hedonic reactions, release of DA in this area is likely to be a consequence rather than the cause of the appetitive properties of taste stimuli, consistent with the idea that taste-hedonia does not depend on DA (Berridge and Robinson, 1998). These observations, however, leave open the issue of a role of DA in state-hedonia (euphoria, eutimia) as distinct from stimulus-bound (e.g. taste) hedonia. 

Lovibond PF (1983) Facilitation of instrumental behavior by a Pavlovian appetitive conditioned stimulus. J. Exp. Psychol Anim Behav Process 9 225-247. 

Salt and water balance are closely related. Water can remain in the ECF only if accompanied by sodium ions, which are the major cations in the ECF and form 90% of the total cation content. If water is added to the plasma without an appropriate amount of sodium ions to maintain normal osmotic pressure, the water will leave the ECF and move into the body cells. Although thirst is known to be a powerful stimulus to drink and replace the lost water, the corresponding stimulus for salt intake or salt appetite is poorly understood and is probably of minor importance in human subjects. 

The purpose of this study was to make an initial evaluation of the effectiveness of odors normally associated with decomposition for attracting brown tree snakes. We must eschew broad inference from our results because although the compounds we tested were not attractive in these pilot studies, one of these compounds could still be an essential component of an attractive chemical stimulus. Our results firmly suggest, however, that a simple chemical attractant is unlikely to be found by examining individual compounds perceived by humans as important components of the odor of decomposition. More comprehensive testing is required before stronger inference can be made as to the influence these compounds have on appetitive foraging behavior of brown tree snakes, but we do not believe that these compounds will prove useful as artificial lures. 

Lorenz (1981) recognized that some appetitive behaviors are FAPs, endogenously released and terminated upon detection of the key stimulus for the consummatory act that is the objective of the search. But, he did not develop the theoretical implications of this idea. Instead we must turn to the Russian physiologists who have spent 50 years studying orienting reflexes (Sokolov, 1963 Voronin et al., 1965, see also Berlyne, 1960). 

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