start-ver=1.4 cd-journal=joma no-vol=122 cd-vols= no-issue=5 article-no= start-page=1918 end-page=1927 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191025 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Tactile angle discriminability improvement: roles of training time intervals and different types of training tasks en-subtitle= kn-subtitle= en-abstract= kn-abstract=Perceptual learning, which is not limited to sensory modalities such as vision and touch, emerges within a training session and between training sessions and is accompanied by the remodeling of neural connections in the cortex. However, limited knowledge exists regarding perceptual learning between training sessions. Although tactile studies have paid attention to between-session learning effects, there have been few studies asking fundamental questions regarding whether the time interval between training sessions affects tactile perceptual learning and generalization across tactile tasks. We investigated the effects of different training time intervals on the consecutive performance of a tactile angle discrimination (AD) task and a tactile orientation discrimination (OD) task training on tactile angle discriminability. The results indicated that in the short-interval training group, AD task performance significantly improved in the early stage of learning and nearly plateaued in the later stage, whereas in the long-interval training group, significant improvement was delayed and then also nearly plateaued in the later stage; additionally, improved OD task performance resulted in improved AD task performance. These findings suggest that training time interval affects the early stage of learning but not the later stage and that generalization occurs between different types of tactile tasks. en-copyright= kn-copyright= en-aut-name=WangWu en-aut-sei=Wang en-aut-mei=Wu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YangJiajia en-aut-sei=Yang en-aut-mei=Jiajia kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WuQiong en-aut-sei=Wu en-aut-mei=Qiong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YuJiabin en-aut-sei=Yu en-aut-mei=Jiabin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TakahashiSatoshi en-aut-sei=Takahashi en-aut-mei=Satoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=EjimaYoshimichi en-aut-sei=Ejima en-aut-mei=Yoshimichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=WuJinglong en-aut-sei=Wu en-aut-mei=Jinglong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil= Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= en-keyword=between-session learning kn-keyword=between-session learning en-keyword=generalization kn-keyword=generalization en-keyword=tactile angle discriminability kn-keyword=tactile angle discriminability en-keyword=training time interval kn-keyword=training time interval END start-ver=1.4 cd-journal=joma no-vol=5 cd-vols= no-issue=8 article-no= start-page=e02141 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190831 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Stroking hardness changes the perception of affective touch pleasantness across different skin sites en-subtitle= kn-subtitle= en-abstract= kn-abstract=Human unmyelinated tactile afferents (CT afferents) in hairy skin are thought to be involved in the transmission of affective aspects of touch. How the perception of affective touch differs across human skin has made substantial progress; however, the majority of previous studies have mainly focused on the relationship between stroking velocities and pleasantness ratings. Here, we investigate how stroking hardness affects the perception of affective touch. Affective tactile stimulation was given with four different hardness of brushes at three different forces, which were presented to either palm or forearm. To quantify the physical factors of the stimuli (brush hardness), ten na?ve, healthy participants assessed brush hardness using a seven-point scale. Based on these ten participants, five more participants were added to rate the hedonic value of brush stroking using a visual analogue scale (VAS). We found that pleasantness ratings over the skin resulted in a preference for light, soft stroking, which was rated as more pleasant when compared to heavy, hard stroking. Our results show that the hairy skin of the forearm is more susceptible to stroking hardness than the glabrous of the palm in terms of the perception of pleasantness. These findings of the current study extend the growing literature related to the effect of stroking characteristics on pleasantness ratings. en-copyright= kn-copyright= en-aut-name=YuJiabin en-aut-sei=Yu en-aut-mei=Jiabin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YangJiajia en-aut-sei=Yang en-aut-mei=Jiajia kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YuYinghua en-aut-sei=Yu en-aut-mei=Yinghua kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=WuQiong en-aut-sei=Wu en-aut-mei=Qiong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TakahashiSatoshi en-aut-sei=Takahashi en-aut-mei=Satoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=EjimaYoshimichi en-aut-sei=Ejima en-aut-mei=Yoshimichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=WuJinglong en-aut-sei=Wu en-aut-mei=Jinglong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Interdisciplinary, Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Interdisciplinary, Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Interdisciplinary, Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Interdisciplinary, Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Interdisciplinary, Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Cognitive Neuroscience Laboratory, Graduate School of Interdisciplinary, Science and Engineering in Health Systems, Okayama University kn-affil= en-keyword=Affective tactile kn-keyword=Affective tactile en-keyword=CT afferents; Neuroscience kn-keyword=CT afferents; Neuroscience en-keyword=Physical factors kn-keyword=Physical factors en-keyword=Pleasantness ratings kn-keyword=Pleasantness ratings en-keyword=Stroking hardness. kn-keyword=Stroking hardness. END