The video I am posting today refers to some of my pilot testing.
At the moment I am interested in the neurophysiological bases of the perception
of skin wetness. As part of my PhD I am using psychophysical methods to
investigate the individual role of each sensory component (i.e. thermal and
mechanical sense) involved in this complex perception (Filingeri, Redortier, Hodder, & Havenith, 2013a,
2013b; 2013c).
Indeed, the perception of skin wetness seems resulting from the
intra-sensory integration of temperature and mechanical inputs. The activity of
cold sensitive thermoreceptors and mechanoreceptors responding to these
physical inputs is proposed as to play a fundamental role in this percept (Ackerley, Olausson, Wessberg, & McGlone, 2012). Cold and mechanical stimuli are
coded by large myelinated A-nervous fibers (whereas small unmyelinated
C-nervous fibers respond to warm and noxious thermal stimuli) (Campero, Serra, Bostock, & Ochoa, 2001; Davis,
1998).
In this video you can appreciate the thermal changes (in
terms of skin temperature) occurring on the forearm during a 25 min full blood
flow occlusion (inducing compression ischemia). This was performed at an ambient
temperature of 22°C. The video has been recorded with a thermal cam (T620, FLIR,
USA) which allows a very detailed infrared thermography.
Compression ischemia (e.g. as resulting from inflating a
blood cuff around the arm with a supra-systolic pressure) has been shown to be
an effective method to selectively block the activity of A-nervous fibers (Mackenzie, Burke, Skuse, & Lethlean, 1975). These fibers have higher metabolic demands than smaller C-fibers. During a full blood flow
occlusion, these fibers will stop their conducting activity earlier than the
C-fibers (Craig & Bushnell, 1994; Kandel, Schwartz, &
Jessell, 2000).
Thus, the selective block of specific receptors allows the investigation of the sensory
inputs which the central nervous system relies on when elaborating complex
sensory experiences such as skin wetness.
The key points of the video, which I would like to drive
your attention to, are the dramatic drop in the hand’ skin temperature
occurring throughout the occlusion protocol, as well as the fastreperfusion occurring as soon as the occlusion is terminated and the blood
is free to flush back into the forearm (jump to minute 4 to see that).
Enjoy it!
Davide Filingeri
PhD Researcher
Environmental Ergonomics Research Centre
Loughborough University, UK
References
Ackerley, R., Olausson, H., Wessberg,
J., & McGlone, F. (2012). Wetness perception across body sites. Neuroscience
letters, 522(1), 73-7. Elsevier Ireland Ltd.
doi:10.1016/j.neulet.2012.06.020
Campero, M.,
Serra, J., Bostock, H., & Ochoa, J. L. (2001). Slowly conducting afferents activated
by innocuous low temperature in human skin. The Journal of physiology, 535(Pt
3), 855-65. Retrieved from
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2278822&tool=pmcentrez&rendertype=abstract
Craig, A., & Bushnell, M. (1994). The thermal grill
illusion: unmasking the burn of cold pain. Science, 148(1991).
Retrieved from
http://psycnet.apa.org/?fa=main.doiLanding&uid=1995-04211-001
Davis, K. D. (1998). Cold-induced pain and prickle in the
glabrous and hairy skin. Pain, 75(1), 47-57. Retrieved from
http://www.ncbi.nlm.nih.gov/pubmed/9539673
Filingeri, D, Redortier, B., Hodder, S., & Havenith,
G. (2013a). The role of decreasing contact temperatures in the perception of
wetness on the skin. In J. D. Cotter, S. J. E. Lucas, & T. Mundel (Eds.), 15th
International Conference on Environmental Ergonomics, 2013 (p. 174).
Queenstown, New Zealand,. Retrieved from
https://dspace.lboro.ac.uk/dspace-jspui/handle/2134/11958
Filingeri, D, Redortier, B., Hodder, S., & Havenith,
G. (2013b). Individual ability to discriminate between wetness and dryness
during short contacts with a warm surface. In J. D. Cotter, S. J. E. Lucas,
& T. Mundel (Eds.), 15th International Conference on Environmental
Ergonomics, 2013 (p. 180). Queenstown, New Zealand,: International Society
for Environmental Ergonomics © the authors. Retrieved from
https://dspace.lboro.ac.uk/dspace-jspui/handle/2134/11957
Filingeri, Davide, Redortier, B., Hodder, S. G., &
Havenith, G. (2013c). The role of thermal and touch sense in the perception of
skin wetness at rest and during exercise in different environments. 18th
Annual Congress of the European College of Sport Science.
Kandel, E. R., Schwartz, J. H., & Jessell, T. M.
(2000). Principles of neural sciences. USA ET - 4th: McGraw-Hill.
Mackenzie, R. a, Burke, D., Skuse, N. F., & Lethlean,
a K. (1975). Fibre function and perception during cutaneous nerve block. Journal
of neurology, neurosurgery, and psychiatry, 38(9), 865-73. Retrieved
from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=492115&tool=pmcentrez&rendertype=abstract
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