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Laura Grandi* 30/11/2015 10 am

Pleasant sweeping grooming touch in rhesus monkey: effects on autonomic nervous system and modulation of insula and secondary somatosensory cortex activity

Several human studies have investigated the affiliative social skin-to-skin interpersonal touch, showing that the gentle social touch performed at velocity of 1-10 cm/sec 1) is perceived as pleasant; 2) activates the C tactile (CT) fibers on the hairy side of the skin; 3) has relaxing cardiac effects and 4) determines the modulation of the brain regions involved in the coding of the affiliative meaning of the sensory peripheral stimulation. In particular, the insular cortex has a central role in processing gentle touch following activation of CT fibers.

Like gentle caress for humans, in the same way allo-grooming, is a social affiliative behavior for non-human primates. It has been recently proposed the role of CT fibers during the sweeping occurred during allo-grooming, but up to now there is no direct evidence in support of this hypothesis. We investigated the codification of sweeping touch at central nervous system level and its effects on autonomic system in a male rhesus monkey.

The preliminary data here presented show that the sweeping at velocity of 5-10 cm/sec determined 1) the modulation of both insular and secondary somatosensory cortex, 2) the decrement of heart rate and increment of heart rate variability, and 3) the increment of the face skin temperature These results support the hypothesis of the involvement of CT fibers during sweeping grooming. Furthermore the present study represents the first evidence of the representation of the affiliative gentle sweeping at both autonomic and central nervous system in non-human primates

*PhD student at Department of Neuroscience, Physiology Unit, University of Parma, Italy

Department of Neuroscience - Section of Physiology University of Parma, Via Volturno 39, I-42125 Parma, Italy Phone: +39-0521-033847; Fax: +39-0521-903879 E-mail:; Skype: Laura Clara Grandi

— Posted by Michelle Soulier on 2015-11-24 08:29 (more news...)