Abstract
Being groomed or touched can counter stress and negative affect in mammals. In two experiments we explored whether a similar phenomenon exists in non-mammals like zebrafish. In Experiment 1, we exposed zebrafish to a natural stressor, a chemical alarm signal released by injured conspecifics. Before moving them into an observation tank, one group of fish was washed and then subjected to a water current that served as the tactile stimulus. The other group was simply washed. Fish with tactile treatment demonstrated fewer fear behaviors (e.g., bottom dwelling) and lower cortisol levels than fish without. In Experiment 2, we ascertained a role of somatosensation in these effects. Using a similar paradigm as in Experiment 1, we recorded fear behaviors of intact fish and fish with damaged lateral line hair cells. Relative to the former, the latter benefited less from the tactile stimulus during fear recovery. Together these findings show that tactile stimulation can calm fish and that tactile receptors, evolutionarily older than those present in mammals, contribute to this phenomenon.
Highlights
IntroductionEven if transient, induce an unpleasant state. The narrow escape from a car accident, the passing of a shadowy figure in the dark, or the temporary fright of having lost something dear can chill us to the bone and may linger with us for hours or days
Threats, even if transient, induce an unpleasant state
As in Experiment 1, we observed large differences between fish exposed to SS as a function of whether or not these fish were subsequently treated with water current
Summary
Even if transient, induce an unpleasant state. The narrow escape from a car accident, the passing of a shadowy figure in the dark, or the temporary fright of having lost something dear can chill us to the bone and may linger with us for hours or days. Being spoken to, but perhaps more importantly, being affectionately touched can go a long way in restoring one’s sense of calm. We explored calming through touch in terms of its ubiquity in the animal kingdom and its biological underpinnings. Human touch has a long history in healing and medical therapy. Modern empirical work corroborated this by showing that a few minutes of massage reduce stress hormones and increase the circulation of chemicals that counteract physiological arousal (Morhenn et al, 2012). Repeated massages over the course of days or weeks were found helpful in a number of conditions ranging from insomnia (Oliveira et al, 2012) to depression and cancer (Noto et al, 2010; Krohn et al, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
