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1.
PLoS One ; 13(12): e0206905, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30543628

RESUMO

It has been demonstrated that nurturing and affiliative touch is essential for human emotional and physical well-being throughout our entire life. Within the last 30 years a system of low-threshold mechanosensitive C fibers innervating the hairy skin was discovered and described; this system is hypothesized to represent the neurobiological substrate for the affective and rewarding properties of touch. This discovery opens new perspectives for multidisciplinary research of the role of affiliative social touch in health and disease, and calls for establishing novel psychometric tools assessing individual differences in the domain of affective touch. The main objective of the study was to construct and validate a Russian version of the Touch Experiences and Attitudes Questionnaire (TEAQ), a self-report measure recently developed to quantify individual experience and attitude to social and affective touch. A pool of 117 items was translated into Russian and all the items were assessed for appropriateness for Russian culture (232 participants). After exploring the factor structure (468 participants), we composed a 37-item questionnaire (TEAQ-37 Rus) characterized by good reliability and a clear 5-factor structure, covering the aspects of attitude to intimate touch, attitude to friendly touch, attitude to self-care, current intimate touch experiences, and childhood touch experiences. Confirmatory factor analysis (551 participants) has demonstrated good consistency and reliability of the 5-factor structure of the TEAQ-37 Rus. Cross-validation research demonstrated moderate positive correlations between predisposition to social touch and emotional intelligence; positive correlations with extraversion and openness facets of the Big Five personality model were also found. As predicted, participants with higher TEAQ-37 Rus scores rated all observed kinds of touch as more pleasant, with a particular preference for slow touch. We anticipate that this questionnaire will be a valuable tool for researchers of social touch, touch perception abnormalities, and the importance of touch experiences for emotional and mental health.


Assuntos
Atitude , Idioma , Inquéritos e Questionários , Tato , Adolescente , Adulto , Afeto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Reprodutibilidade dos Testes , Federação Russa , Adulto Jovem
2.
Biol Psychol ; 129: 186-194, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28865933

RESUMO

The rewarding sensation of touch in affiliative interactions is hypothesised to be underpinned by an unmyelinated system of nerve fibres called C-tactile afferents (CTs). CTs are velocity tuned, responding optimally to slow, gentle touch, typical of a caress. Here we used evaluative conditioning to examine whether CT activation carries a positive affective value. A set of neutral faces were paired with robotically delivered touch to the forearm. With half the faces touch was delivered at a CT optimal velocity of 3cm/s (CT touch) and with the other half at a faster, non-CT optimal velocity of 30cm/s (Control touch). Heart-rate and skin conductance responses (SCRs) were recorded throughout. Whilst rated equally approachable pre-conditioning, post-conditioning faces paired with CT touch were judged significantly more approachable than those paired with Control touch. CT touch also elicited significantly greater heart-rate deceleration and lower amplitude SCRs than Control touch. The results indicate CT touch carries a positive affective value, which can be acquired by socially relevant stimuli it is associated with.


Assuntos
Reconhecimento Facial/fisiologia , Motivação/fisiologia , Neurônios Aferentes/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Adulto , Feminino , Resposta Galvânica da Pele/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Estimulação Física/métodos , Adulto Jovem
3.
Neuropeptides ; 64: 27-38, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28162847

RESUMO

Low intensity, non-noxious, stimulation of cutaneous somatosensory nerves has been shown to trigger oxytocin release and is associated with increased social motivation, plus reduced physiological and behavioural reactivity to stressors. However, to date, little attention has been paid to the specific nature of the mechanosensory nerves which mediate these effects. In recent years, the neuroscientific study of human skin nerves (microneurography studies on single peripheral nerve fibres) has led to the identification and characterisation of a class of touch sensitive nerve fibres named C-tactile afferents. Neither itch nor pain receptive, these unmyelinated, low threshold mechanoreceptors, found only in hairy skin, respond optimally to low force/velocity stroking touch. Notably, the speed of stroking which C-tactile afferents fire most strongly to is also that which people perceive to be most pleasant. The social touch hypothesis posits that this system of nerves has evolved in mammals to signal the rewarding value of physical contact in nurturing and social interactions. In support of this hypothesis, we review the evidence that cutaneous stimulation directly targeted to optimally activate C-tactile afferents reduces physiological arousal, carries a positive affective value and, under healthy conditions, inhibits responses to painful stimuli. These effects mirror those, we also review, which have been reported following endogenous release and exogenous administration of oxytocin. Taken together this suggests C-tactile afferent stimulation may mediate oxytocin release during affiliative tactile interactions.


Assuntos
Emoções/fisiologia , Ocitocina/metabolismo , Pele/metabolismo , Comportamento Social , Animais , Humanos , Fibras Nervosas Amielínicas/metabolismo , Estimulação Física/métodos , Pele/inervação
4.
Behav Brain Res ; 320: 91-96, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-27915070

RESUMO

A subclass of C-fibres, C-tactile afferents (CTs), have been discovered which respond preferentially to low force/velocity stroking touch, that is typically perceived as pleasant. Molecular genetic visualization of these low-threshold mechanosensitive C-fibres (CLTMs) in mice revealed a denser distribution in dorsal than ventral thoracic sites, scattered distal limb innervation and a complete absence from glabrous paw skin (Liu et al., 2007). Here we used third-party ratings to examine whether affective responses to social touch reflect the anatomical distribution and velocity tuning of CTs. Participants viewed and rated a sequence of video clips depicting one individual being touched by another at different skin sites and at 3 different velocities (static, 3cm/s, 30cm/s). Immediately after viewing each clip participants were asked to rate how pleasant they perceived the touch to be. Vicarious preferences matched the previously reported anatomical innervation density of rodent CLTMs, with touch on the back being rated significantly more pleasant than any other location. Furthermore, in contrast to all other skin sites, CT optimal (3cm/s) touch on the palm of the hand was not preferred to static touch, consistent with the anatomical absence of CTs in glabrous skin. Our findings demonstrate that humans recognise the specific rewarding value of CT optimal caressing touch and their preferences reflect the hypothesised anatomical distribution of CTs.


Assuntos
Emoções , Fibras Nervosas Amielínicas/fisiologia , Comportamento Social , Percepção do Tato/fisiologia , Tato/fisiologia , Feminino , Humanos , Masculino , Estimulação Física , Estatísticas não Paramétricas , Adulto Jovem
5.
Eur J Neurosci ; 45(2): 232-237, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27859794

RESUMO

Affective touch sensation is conducted by a sub-class of C-fibres in hairy skin known as C-Tactile (CT) afferents. CT afferents respond maximally to gentle skin stroking at velocities between 1 and 10 cm/s. Parkinson's disease (PD) is characterised by markedly reduced cutaneous C-fibres. It is not known if affective touch perception is influenced by C-fibre density and if affective touch is impaired in PD compared to healthy controls. We predicted that perceived pleasantness to gentle stroking in PD would correlate with C-afferent density and that affective touch perception would be impaired in PD compared to healthy controls. Twenty-four PD patients and 27 control subjects rated the pleasantness of brush stroking at an optimum CT stimulation velocity (3 cm/s) and two sub-optimal velocities (0.3 and 30 cm/s). PD patients underwent quantification of C-fibre density using skin biopsies and corneal confocal microscopy. All participants rated a stroking velocity of 3 cm/s as the most pleasant with significantly lower ratings for 0.3 and 30 cm/s. There was a significant positive correlation between C-fibre density and pleasantness ratings at 3 and 30 cm/s but not 0.3 cm/s. Mean pleasantness ratings were consistently higher in PD patients compared to control subjects across all three velocities. This study shows that perceived pleasantness to gentle touch correlates significantly with C-fibre density in PD. The higher perceived pleasantness in PD patients compared to controls suggests central sensitisation to peripheral inputs, which may have been enhanced by dopamine therapy.


Assuntos
Mecanorreceptores/fisiologia , Doença de Parkinson/fisiopatologia , Neuropatia de Pequenas Fibras/fisiopatologia , Percepção do Tato/fisiologia , Tato/fisiologia , Emoções/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fibras Nervosas Amielínicas/fisiologia , Estimulação Física/métodos , Pele/inervação
6.
Eur J Neurosci ; 44(4): 2072-83, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27307373

RESUMO

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 h, participants underwent an fMRI scan, during which time CT-innervated forearm skin and CT non-innervated finger skin was stroked with three 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. In addition, 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 similar 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.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Percepção do Tato/fisiologia , Triptofano/metabolismo , Adulto , Afeto/fisiologia , Emoções , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Estimulação Física/métodos , Tato/fisiologia
7.
Neuroimage Clin ; 4: 701-10, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24936421

RESUMO

BACKGROUND: Major depressive disorder (MDD) is associated with functional abnormalities in fronto-meso-limbic networks contributing to decision-making, affective and reward processing impairments. Such functional disturbances may underlie a tendency for enhanced altruism driven by empathy-based guilt observed in some patients. However, despite the relevance of altruistic decisions to understanding vulnerability, as well as everyday psychosocial functioning, in MDD, their functional neuroanatomy is unknown. METHODS: Using a charitable donations experiment with fMRI, we compared 14 medication-free participants with fully remitted MDD and 15 demographically-matched control participants without MDD. RESULTS: Compared with the control group, the remitted MDD group exhibited enhanced BOLD response in a septal/subgenual cingulate cortex (sgACC) region for charitable donation relative to receiving simple rewards and higher striatum activation for both charitable donation and simple reward relative to a low level baseline. The groups did not differ in demographics, frequency of donations or response times, demonstrating only a difference in neural architecture. CONCLUSIONS: We showed that altruistic decisions probe residual sgACC hypersensitivity in MDD even after symptoms are fully remitted. The sgACC has previously been shown to be associated with guilt which promotes altruistic decisions. In contrast, the striatum showed common activation to both simple and altruistic rewards and could be involved in the so-called "warm glow" of donation. Enhanced neural response in the depression group, in areas previously linked to altruistic decisions, supports the hypothesis of a possible association between hyper-altruism and depression vulnerability, as shown by recent epidemiological studies.


Assuntos
Altruísmo , Tomada de Decisões/fisiologia , Transtorno Depressivo Maior/patologia , Transtorno Depressivo Maior/psicologia , Giro do Cíngulo/patologia , Adulto , Feminino , Giro do Cíngulo/irrigação sanguínea , Humanos , Processamento de Imagem Assistida por Computador , Modelos Lineares , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Escalas de Graduação Psiquiátrica , Tempo de Reação
8.
Cytokine ; 45(1): 1-7, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19026559

RESUMO

Interleukin (IL)-1 is a pivotal pro-inflammatory cytokine and an important mediator of both acute and chronic central nervous system (CNS) injuries. Despite intense research in CNS IL-1 biology over the past two decades, its precise mechanism of action in inflammatory responses to acute brain disorders remains largely unknown. In particular, much effort has been focussed on using in vitro approaches to better understand the cellular and signalling mechanisms of actions of IL-1, yet some discrepancies in the literature regarding the effects produced by IL-1beta in in vitro paradigms of injury still exist, particularly as to whether IL-1 exerts neurotoxic or neuroprotective effects. Here we aim to review the cell-specific and concentration-dependent actions of IL-1 in brain cells, to depict the mechanism by which this cytokine induces neurotoxicity or neuroprotection in acute brain injury.


Assuntos
Encefalite/imunologia , Interleucina-1/imunologia , Animais , Encefalite/patologia , Humanos , Neuroglia/metabolismo , Neurônios/metabolismo , Fármacos Neuroprotetores/metabolismo , Transdução de Sinais/fisiologia
9.
West Indian med. j ; 50(Suppl 5): 37, Nov. 2001.
Artigo em Inglês | MedCarib | ID: med-120

RESUMO

OBJECTIVE: The study was initiated to establish guidelines for the application of theory-based health promotion strategies in diet and exercise behaviour. The selected theory is the Trans-theoretical Model of Behaviour Change. The study utilizes three of the core constructs of the trans-theoretical model: the stages of change (the central organizing construct); decisional balance; and self-efficacy in examining fruit and vegetable consumption and exercise participation among adults 18 to 65 years old. The qualitative results are highlighted in this report. METHODS: The qualitative phase of the study was conducted in four countries: Belize, Jamaica, St.Kitts/Nevis and Trinidad and Tobago. Between 7 and 10 focus group discussions were conducted in each country. The variables for selecion of participants were: age range, gender, obesity stage, residential location and socio-economic status. RESULTS: The qualitative phase results indicated that, in the population studied, size was a very important determinant of perceived beauty, social adequacy, functioning and responsiveness. Knowledge relating to lifestyle is high but there is reluctance to effect lifestyle changes in dietary intake and physical activity. Cable television was identified as contributing to these current perceptions. Men were less concerned than women about their weight. Neither fruits nor vegetables were frequently mentioned as forming a part of daily diets of the majority of participants. Physical exercise was generally regarded ad hard work. CONCLUSIONS: The qualitative results of this study show that our approach to obesity prevention requires radical change. (AU)


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Estudo Comparativo , Obesidade/epidemiologia , Dieta , Exercício Físico , Obesidade/prevenção & controle , Região do Caribe/epidemiologia , Comportamento
12.
Washington, D.C; Pan Américan Health Organization; 2001. 38 p. (PAHO/HPP/HPN/MC/49-16).
Monografia em Inglês | LILACS | ID: lil-381832
13.
St. Augustine; Caribbean Food and Nutrition Institute; 1992. 38 p. tab. (CFNI-T-3-92).
Monografia em Inglês | MedCarib | ID: med-15066
14.
St. Augustine; Caribbean Food and Nutrition Institute; 1992. 38 p. tab. (CFNI-T-3-92).
Monografia em Inglês | LILACS | ID: lil-142581
16.
Kingston; Caribbean Food and Nutrition Institute; Nov. 1988. 26 p. tab. (CFNI-J-7A-88).
Monografia em Inglês | MedCarib | ID: med-15335
19.
St. Augustine; Caribbean Food and Nutrition Institute; May 1986. 79 p. (CFNI-T-8-86).
Monografia em Inglês | MedCarib | ID: med-15153
20.
St. Augustine; Caribbean Food and Nutrition Institute; May 1986. 79 p. (CFNI-T-8-86).
Monografia em Inglês | LILACS | ID: lil-142556
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