Skin conductance responses

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... 

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). 

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. 

Compared to other biosignals taken from the skin, electrodermal activity (EDA) can be r arded as the most convenient measure for workload. Phasic EDA is measured as skin conductance response (SCR) or skin resistance response (SRR). SCR amplitudes may reflect the amount of affective or emotional arousal elicited by a stimulus or situation (see Fig. 1.1). Both amplitude and recovery of an EDR have been demonstrated to be sensitive for certain aspects of central information processing (Boucsein, 1992), and may be used in a manner similar to ERPs as indicators of mental strain. The frequency of spontaneous electrodermal changes (called... 

Note. HCI = human-computer interaction SCR = skin conductance response SRL = skin resistance level SRR = skin resistance response SRT = system response time NS.SCR = nonspecific skin conductance response. 

Since that time, little progress has been made in the area of psychophysiologically based adaptive systems. To date, there are only a few examples of such systems. Yamamoto and Isshiki (1992) described one system that uses skin conductance responses (SCR) to maintain alertness. In their system, skin conductance is measured continuously for spontaneous changes. If 3 minutes elapse without a change, an auditory alarm sounds. The subjects in their study were expected to expend effort at the sound of the alarm and therefore change their SCR, which in turn would shut off the alarm. The system described by Yamamoto and Isshiki functions as a simple alertness monitor and therefore does not truly represent an application of adaptive automation. Recently, however, a prototype of an adaptive system for moderating operator workload that is driven by changes in EEG has been described. 

Tranel, D., and Damasio, H. 1994. Neuroanatomical correlates of electrodermal skin conductance responses. Psychophysiology, 31, 427-438. 

ADO 10] Adolph D., Schlosser S., Hawighorst M. et al, Chemosensory signals of competition increase the skin conductance response in humans , Physiology Behavior, vol. 101, pp. 666-671, 2010. 

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. 

Polybrominated Diphenyl Ethers. A human sensitization study was conducted in which 77.4% decaBDE (containing 21.8% nonaBDE and 0.8% octaBDE) as a 5% suspension in petrolatum was applied via patch, 3 times a week for 3 weeks, to 50 subjects (Norris et al. 1975a). No skin sensitization responses... 

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). 

Skin conductivity (also called electrodermal response or Galvanic Skin Response, GSR) is thought to be an indicator of psychological, emotional or physiological arousal. Measurement of skin conductivity is typically performed by an ohmmeter in which a constant 0.5 V is applied between the electrodes and the resulting current flow is measured by amplifying the voltage across a resistor in series with the skin [5]. 

EDA is divided into tonic (level) and phasic (response) phenomena. Both tonic levels (skin conductance level, skin potential level) and responses (SCR, skin potential response) are of interest working with EDA. They are generated under autonomous nerve control of the active organs of the skin, in particular the sweat glands. 

Tronstad, C., Kalvpy, H., Grimnes, S., Martinsen, 0.G., 2013. Waveform difference between skin conductance and skin potential responses in relation to electrical and evaporative properties of skin. Psychophysiology 50, 1070-1078. 

Reports have appeared in the Hterature of the use of human growth hormone in older men. It has been proposed that a reduction in growth hormone in old age is responsible for increased adipose tissue, loss of lean body mass, and thinning of skin. Current studies conducted on older men indicate the hormone reverses these effects. In the parameters studied the patients resembled those of persons 10 —20 years younger (70). 

Only a few in vivo dermal toxicity studies have been reported so far. Huczko and Lange [50] evaluated the potential of raw CNTs to induce skin irritation by conducting two routine dermatological tests (patch test on 40 volunteers with allergy susceptibilities and Draize rabbit eye test on four albino rabbits). Koyama etal. [51] showed the biological responses to four different types of carbon nanotubes (SWNTs, two types of MWNTs with different diameters, and cup-stacked carbon nanotubes) after their subcutaneous implantation in mice. Both tests [50, 51] showed no or poor irritation effects. However, the in vitro studies in epidermal cell lines exposed to CNTs, and also a more recent report on the toxic outcomes of topical exposure of mice to SWNTs [46], have raised concerns over these assessments. Clearly, this is an area requiring further scientific evaluation. 

---