Trotter, PD and McGlone, FP and McKie, S and McFarquhar, M and Elliott, R and Walker, SC and Deakin, JF (2016) Effects of acute tryptophan depletion on central processing of CT-targeted and discriminatory touch in humans. European Journal of Neuroscience. ISSN 1460-9568
EJN Imaging Proof Manuscript.pdf - Accepted Version
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C-tactile afferents (CTs) are slowly conducting nerve fibres, present only in hairy skin. They are optimally activated by slow, gentle stroking touch, such as those experienced during a caress. CT-stimulation activates affective processing brain regions, alluding to their role in affective touch perception. We tested a theory that CT-activating touch engages the pro-social functions of serotonin, by determining whether reducing serotonin, through acute tryptophan depletion, diminishes subjective pleasantness and affective brain responses to gentle touch. A tryptophan depleting amino acid drink was administered to 16 healthy females, with a further 14 receiving a control drink. After 4 hours, participants underwent an fMRI scan, during which time CT-innervated forearm skin and CT non-innervated finger skin was stroked with 3 brushes of differing texture, at CT-optimal force and velocity. Pleasantness ratings were obtained post-scanning. The control group showed a greater response in ipsilateral orbitofrontal cortex to CT-activating forearm touch compared to touch to the finger where CTs are absent. This differential response was not present in the tryptophan depleted group. This interaction effect was significant. Additionally, control participants showed a differential primary somatosensory cortex response to brush texture applied to the finger, a purely discriminatory touch response, which was not observed in the tryptophan depleted group. This interaction effect was also significant. Pleasantness ratings were comparable across treatment groups. These results implicate serotonin in the differentiation between CT-activating and purely discriminatory touch responses. Such effects could contribute to some of the social abnormalities seen in psychiatric disorders associated with abnormal serotonin function. This article is protected by copyright. All rights reserved.
|Additional Information:||This is the peer reviewed version of the following article: Effects of acute tryptophan depletion on central processing of CT-targeted and discriminatory touch in humans. Paula Diane Trotter, Francis McGlone, Shane McKie, Martyn McFarquhar, Rebecca Elliott, Susannah Claire Walker, John Francis William Deakin, European Journal of Neuroscience: DOI: 10.1111/ejn.13298 which has been published in final form at http://dx.doi.org/10.1111/ejn.13298 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."|
|Uncontrolled Keywords:||1109 Neurosciences, 1702 Cognitive Science, 1701 Psychology|
|Subjects:||R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry|
|Divisions:||Natural Sciences and Psychology|
|Date Deposited:||29 Jun 2016 08:31|
|Last Modified:||04 Jul 2016 10:19|
|DOI or Identification number:||10.1111/ejn.13298|
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