Skin conductance

The role of caffeine in stress and stress reactions has been well documented.206 It affects the neuroendocrine107 and heart rate207 208 responses to stress, as well as the skin conductance response to stressful anagram... 

High levels of resting peripheral indicators of autonomic activity and reduced responsiveness of these indicators (including skin conductance and heart rate) have been found in adult-onset schizophrenia. Similar patterns were seen for COS patterns in the NIMH sample. 

The most common psychophysiologic measures recorded from antisocial populations have been EEG and event-related potentials (ERPs), heart rate (HR), and skin conductance (SC) (Scarpa and Raine, 1997). 

Skin conductance represents changes in the electrical activity of skin. Resting skin conductance level (SCL) and the number of nonspecific fluctuations (spontaneous skin conductance responses [SCRs] seen in a resting state) are thought to reflect arousal. Skin conductance responses are also seen 1 to 3 seconds after stimulus onset, when they index the orienting reflex, which measures allocation of attention to the stimulus. Although SC arousal studies show some consistency, 4 out of 10 showed underarousal in antisocial-spectrum subjects no specific links to violence are reported (Scarpa and Raine, 1997). 

INSIGHT uses the fundamental correlation between the electrical and permeability properties of skin. Skin permeability shows a strong correlation with skin impedance, as shown in Figure 4B. Figure 4B shows 150 independent and simultaneous measurements of mannitol skin permeability and skin impedance for six different enhancer formulations. The relationship between skin impedance and permeability to hydrophilic solutes confirms that the former can be used as a surrogate measure for the later. Skin conductance is quick and easy to obtain and does not require additional sample handling and analysis. 

Scott, E.R., A.I. Laplaza, H.S. White, and J.B. Phipps. 1993. Transport of ionic species in skin Contribution of pores to the overall skin conductance. Pharm Res 10 1699. 

Naliboff, B. D., Rickies, W. H., Cohen, M. J., and Naimark, R. S. (1976). Interactions of marijuana and induced stress Forearm blood flow, heart rate, and skin conductance. Psychophysiology 13,... 

Figure 5.1 IB, obtained under the same operating conditions, shows that the skin conductivity enhancement for mannitoi as measured after 24 h of US pre-treatment was propor-tionai to the pre-treatment time [119], Aiso, increasing the overaii US-appiication time and puise iength in the transdermai deiivery of insuiin to hairiess rats enhanced transport of the drug and iowered the biood giucose ievei as a resuit [118],...

Figure 5.11C iiiustrates the dependence of the skin conductivity enhancement on the distance of the horn from the skin at an appiication time of 12 min, a frequency of 20 khlz, and an intensity of 7.44 W/cm, using puises 5 s out 10 s. As can be seen, skin conductivity increased with decreasing distance of the horn from the skin. 

Whether or not the fear of fatness seen in patients with anorexia nervosa constitutes a true phobia is a matter of debate. Many patients, although reluctant to gain weight, do not have a true fat phobia (Ngai et al. 2000). In keeping with this view, we found that the change in skin conductance ( psycho-galvanic reflex ) in response to food-related cues in patients with anorexia nervosa was much less than that seen in patients with other phobias when presented with relevant phobic related cues (Salkind et al. 1980). 

In a recent experiment (Becharaetal. 1997) it Is also shown that normal subjects "began to generate anticipatory skin conductance responses (SCKs) whenever they pondered a choice that turned out to be risky, before they knew explicitly that it was risky, whereas patients Iwith prefrontal damage] never developed anticipatory SCRs, although some eventually realized which choices were risky." In other words, conscious awareness of costs and benefits is neither a necessary nor a sufficient condition for rational choice. 

EEGs Heart rate Blood pressure Pupil dilation Skin conductivity Level of adrenaline in blood... 

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