Stimulus-response relationship

Kenakin, T. P., and Beek, D. (1980). Is prenalterol (H 133/80) really a selective beta-1 adrenoceptor agonist Tissue selectivity resulting selective beta-1 adrenoceptor agonist Tissue selectivity resulting from difference in stimulus-response relationships. J. Pharmacol. Exp. Ther. 213 406—413. 

As noted above, Passmore et al. (2003) were the first to demonstrate that Kv7.2, 7.3 and 7.5 are expressed at the protein level in sensory neurons and also that functional M-currents can be measured under voltage-clamp. They were further able to demonstrate that pharmacological activation of Kv7 channels by direct application of retigabine to the spinal cord inhibited both C fiber and AS fiber-mediated signaling. This was true when the afferent fibers were excited by either electrical or tactile stimuli. Moreover, wind-up , an increased sensitivity of the stimulus/response relationship to repetitive stimuli, is also inhibited. These results demonstrate a clear role of Kv7 channels in sensory neuron processing. Gerlach et al. (2006, 2007) have also reported direct effects of ICA-27243 on both M-currents and membrane potential in isolated DRG neurons. Activation of the M-current by ICA-27243... 

Figure 7.4 The stimulus-response relationships in classical and operant conditioning overlap.

The stimulus-response relationship between the shear stress and shear strain is given by the shear modulus G ... 

In the semilogarithmic plot (Figure 112.1a), the curves have the same sigmoidal shape and differ only by lateral displacement. The symmetrical sigmoidal shape is a property of the hyperbolic saturation function, which is frequently used to fit fluence-response curves and other types of stimulus-response relationships in sensory physiology, - in photochemical kinetics, and in other areas of biophysics and biology, including the well-known MichaeHs-Menten enzyme kinetics (see below). 

The operational model, as presented, shows dose-response curves with slopes of unity. This pertains specifically only to stimulus-response cascades where there is no cooperativity and the relationship between stimulus ([AR] complex) and overall response is controlled by a hyperbolic function with slope = 1. In practice, it is known that there are experimental dose-response curves with slopes that are not equal to unity and there is no a priori reason for there not to be cooperativity in the stimulus-response process. To accommodate the fitting of real data (with slopes not equal to unity) and the occurrence of stimulus-response cooperativity, a form of the operational model equation can be used with a variable slope (see Section 3.13.4) ... 

Hyperbola (hyperbolic), a set of functions defining nonlinear relationships between abscissae and ordinates. This term is used loosely to describe nonlinear relationships between the initial interaction of molecules and receptors and the observed response (i.e., stimulus-response cascades of cells). 

Except for the case of an ideal plug flow reactor, different fluid elements will take different lengths of time to flow through a chemical reactor. In order to be able to predict the behavior of a given piece of equipment as a chemical reactor, one must be able to determine how long different fluid elements remain in the reactor. One does this by measuring the response of the effluent stream to changes in the concentration of inert species in the feed stream—the so-called stimulus-response technique. In this section we will discuss the analytical form in which the distribution of residence times is cast, derive relationships of this type for various reactor models, and illustrate how experimental data are treated in order to determine the distribution function. 

These relationships show how stimulus-response experiments, using either step or pulse inputs can conveniently give the RTD and mean flow rate of fluid in the vessel. We should remember that these relationships only hold for closed vessels. When this boundary condition is not met, then the and E curves differ. The Cp ise curves of the convection model (see Chap. 15) clearly show this. 

In an examination of the effects of low doses of ondansetron on acquisition of responding for a conditioned reward and on the response-potentiating effect of amphetamine in the rat, ondansetron had no effect on the learning of stimulus reward relationships but caused a small attenuation of the amphetamine effect, suggesting a possible modulatory role for 5-HTj receptors in this process (P. J. Fletcher and Higgins 1997]. 

The dose of anesthetic gas that is being administered can be stated in multiples of MAC. A dose of 1 MAC of any anesthetic prevents movement in response to surgical incision in 50% of patients however, individual patients may require 0.5-1.5 MAC. Unfortunately, MAC gives no information about the slope of the dose-response curve. In general, however, the dose-response relationship for inhaled anesthetics is very steep. Therefore, over 95% of patients may fail to respond to a noxious stimulus at 1.1 MAC. 

I am not so sure. There still remains the problem of our consciousness and its relationship to our material form - the Mind / Brain problem. Behavioural psychologists such as Skinner tried to reduce this to one level - the material brain - by viewing the mental or consciousness events from the outside as being merely stimulus-response loops. 

The operational model, as presented, shows dose-response curves with slopes of unity. This pertains specifically only to stimulus-response cascades where there is no cooperativity and the relationship between stimulus ([AR] complex) and overall response is controlled by a hyperbolic function with slope = 1. In practice, it is known that there... 

It can be seen that the relative maxima are completely dependent on efficacy, receptor density, and the efficiency of stimulus-response coupling (x = [R]/KE see Chapter 3). However, the relationship is not a direct one. Figure 5.22 shows the relative maximum response to two agonists in a... 

A generalized analysis of the stimulus-response-recovery cycle and its relationship to receptors has been offered by Dikstein and Sulman... 

Both the intensity and duration of response are dose-dependent, and more important, the dose-response relationship is dynamic. At increasing levels of baseline bronchoconstriction (irrespective of the stimulus), the dose-response curve is shifted to the right, and the duration of bronchodilation is decreased. This shift is reflected in the need for higher, more frequent doses in acute asthma exacerbations the duration of protection against significant provocation is much less than the duration of bronchodilation in chronic stable asthma (see Table 26-8). 

Mathematical models may be classified into deterministic and stochastic models. For deterministic models, knowledge of the relationship between dependent and independent variables is necessary. Consequently, the complex nature of polymer-based heterogeneous materials is rather incompatible with such requirements. Hence, stochastic models become necessary either when the existing knowledge about the stimulus-response behavior of a system is not enough as to ascertain its behavior or when it is not possible to build an efficient deterministic model able to score the system response. 

C. Minimum Alveolar Anesthetic Concentration (MAC) The potency of inhaled anesthetics is best measured by the minimum alveolar anesthetic concentration (MAC), defined as the alveolar concentration required to eliminate the response to a standardized painful stimulus in 50% of patients. Each anesthetic has a defined MAC (see Table 25-2), but tWs value may vary among different patients depending on age, cardiovascular status, and use of adjuvant drugs. Estimations of MAC value suggest a relatively steep dose-response relationship for inhaled anesthetics. MACS for infants and elderly patients are lower than those for adolescents and young adults. When several anesthetic agents are used simultaneously, their MAC values are additive. 

---