Stimulus context

The past two decades have seen enormous advances in our understanding of crustacean chemical communication. Nevertheless, our knowledge is still in its infancy when compared to insects, fish, or mammals. Most research on crustacean behavior in response to chemical stimuli has been conducted in controlled laboratory environments, where often only one stimulus context is tested. For example, the responses of numerous crustacean species to chemicals emitted by potential mates, by conspecific aggressors, or by interspecific enemies have been tested in... 

A previously unexplained observation of a link between nose and gonads — the so-called naso-genital relationship — can now be placed in context. Removal of the relay site for the pump-regulator (see above) by extirpation of the sphenopalatine ganglion was found to result in a state of pseudo-pregnancy (Rosen et al, 1940). Interruption of stimulus access would clearly prevent most uptake through loss of control over the pump. A diestrous state would be induced (Sec. 5.3 below) attributable to the lack of male urinary semiochemicals. 

Effects of TCDD on macrophages have also been examined. When assessed ex vivo, macrophage functions such as tumor cell lysis, phagocytosis and oxidative burst were not suppressed by exposure to TCDD.9396 101 In other experimental systems, exposure to TCDD increases IL-1 and TNF production by macrophages.99 102 103 However, the ability of TCDD to alter IL-1 and TNF production is likely organ- or stimulus-specific, because in the context of respiratory viral infection, exposure to TCDD had no effect on IL-1 or TNF-a levels.80... 

The perceived intensity of a stimulus is often determined by the context in which it appears. 

Odour annoyance as such is seldom measured in a direct way. Usually, the amount of annoyance is inferred from odour concentration by some magic formula, in which also other factors like the frequency of occurrence and the duration of the annoyance, are involved. Since such formula s are not veiy good predictors of the annoyance experienced, some vague statements about the importance of the nature of the stimulus, given the context in which it is presented, are added. 

Duka T, Tasker R, Russell K, Stephens DN (1998) Discriminative stimulus properties of nicotine at low doses the effects of caffeine preload, Behav Pharmacol 9 219-229 Duka T, Seiss E, Tasker R (2002) The effects of extrinsic context on nicotine discrimination, Behav Pharmacol 13 39 7... 

Finally, we have the subtlest category the modulator pheromones. These pheromones change stimulus sensitivity, salience, and sensorimotor integration in the recipient. These pheromones may determine how a recipient organism will respond to a signal in a specific context. This adds another level of complexity to pheromone action. 

Species Target Context Stimulus Effect Reference... 

Chemical cues hold considerable promise for manipulating behavior in vertebrates, provided we understand an animal s natural history, biology, and behavior well. However, the development of chemical attractants, stimulants, inhibitors, and repellents for vertebrates has progressed rather slowly for several reasons. First, chemical stimulus and behavior are not connected as rigidly as in insects, for example. Second, the same stimulus may elicit different behaviors, depending on the state of the recipient and the context. Third, chemical cues often are rather complex mixtures of compounds. Fourth, learning, especially early experience plays a major role in vertebrate, notably mammalian behavior. Finally, many behaviors are modulated by several sensory modalities so that chemical stimuli alone trigger only incomplete responses at best. 

In this context, we focus on G-protein coupled receptors (GPCRs) with seven transmembrane helices (TMHs) that act as the gateway for signal transduction at the cell surface membrane. An external ligand stimulus applied to GPGR induces coupling with G-proteins (G , G and G, etc.), followed by... 

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