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1.
Psychol Med ; : 1-9, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33947486

RESUMO

BACKGROUND: It remains unclear to what extent reduced nutritional intake in anorexia nervosa (AN) is a consequence of a reduced motivational response to food. Although self-reports typically suggest AN patients have a reduced appetitive response, behavioral and neurophysiological measures have revealed evidence for both increased and reduced attentional biases towards food stimuli. The mechanisms influencing food perception in AN, might be clarified using time-sensitive magnetoencephalography (MEG) to differentiate the early (more automatic processing) stages from the late (more controlled) stages. METHODS: MEG was recorded in 22 partially weight-restored adolescent AN patients and 29 age- and gender-matched healthy control (HC) participants during a rapid serial visual presentation paradigm using 100 high-calorie food, 100 low-calorie food, and 100 non-food pictures. Neural sources of event-related fields were estimated using the L2-Minimum-Norm method and analyzed in early (50-300 ms) and late (350-500 ms) time intervals. RESULTS: AN patients rated high-calorie food as less palatable and reported overall less food craving than HC participants. Nevertheless, in response to food pictures AN patients showed relative increased neural activity in the left occipito-temporal and inferior frontal regions in the early time interval. No group differences occurred in the late time interval. CONCLUSIONS: MEG results speak against an overall reduced motivational response to food in AN. Instead, relative increased early food processing in the visual cortex suggests greater motivated attention. A greater appetitive response to food might be an adaptive mechanism in a state of undernourishment. Yet, this relative increased food processing in AN was no longer present later, arguably reflecting rapid downregulation.

2.
Anal Bioanal Chem ; 412(1): 223-232, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31836923

RESUMO

The composition of human sweat-and as a consequence the composition of volatiles released from human skin-strongly depends on genetic preconditions, diet, stress, personal hygiene but also on health status and medication. Accordingly, the composition is a carrier of information on the physical and mental states of a person. Therefore, rapid on-site analysis of the relevant substances may be used for medical diagnosis and medication control or even for psychological characterisation. Ion mobility spectrometry coupled to rapid gas chromatography (GC-IMS) was applied to the analysis of human axillary sweat as a sensitive, selective, rapid, and non-invasive method in a feasibility study. For this purpose, a sampling chamber was designed and manufactured. The design and the experimental setup were validated successfully. At least 179 human metabolites could be detected by GC-IMS from the skin of 7 volunteers. Fifteen metabolites were available in all samples from all volunteers and therefore can be characterised as basic sweat compounds which might enable the localisation of hidden persons. Furthermore, in a preliminary feasibility study, the potential of GC-IMS for differentiating the composition of sweat after physical exercises and in a stressful situation-even gender specific-could be demonstrated. Thus, with GC-IMS, a rapid and mobile analytical tool for the analysis of skin volatiles is available for a broad range of applications, e.g. with regard to axillary odour, human health, nutrition, consumption of remedies or drugs of abuse, the localisation of trapped or hidden persons, or even the characterisation of the reaction on stressful situations. Graphical abstract.


Assuntos
Axila , Cromatografia Gasosa/métodos , Espectrometria de Mobilidade Iônica/métodos , Suor/metabolismo , Feminino , Humanos , Masculino , Pele/metabolismo
3.
Neuroimage ; 136: 174-85, 2016 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-27208859

RESUMO

The anxiety inducing paradigms such as the threat-of-shock paradigm have provided ample data on the emotional processing of predictable and unpredictable threat, but little is known about the processing of aversive, threat-irrelevant stimuli in these paradigms. We investigated how the predictability of threat influences the neural visual processing of threat-irrelevant fearful and neutral faces. Thirty-two healthy individuals participated in an NPU-threat test, consisting of a safe or neutral condition (N) and a predictable (P) as well as an unpredictable (U) threat condition, using audio-visual threat stimuli. In all NPU-conditions, we registered participants' brain responses to threat-irrelevant faces via magnetoencephalography. The data showed that increasing unpredictability of threat evoked increasing emotion regulation during face processing predominantly in dorsolateral prefrontal cortex regions during an early to mid-latency time interval. Importantly, we obtained only main effects but no significant interaction of facial expression and conditions of different threat predictability, neither in behavioral nor in neural data. Healthy individuals with average trait anxiety are thus able to maintain adaptive stimulus evaluation processes under predictable and unpredictable threat conditions.


Assuntos
Adaptação Fisiológica/fisiologia , Antecipação Psicológica/fisiologia , Expressão Facial , Medo/fisiologia , Rede Nervosa/fisiologia , Córtex Pré-Frontal/fisiologia , Adolescente , Mapeamento Encefálico , Medo/psicologia , Feminino , Humanos , Masculino , Valores de Referência , Adulto Jovem
4.
Behav Brain Res ; 307: 84-91, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27036648

RESUMO

The visual processing of emotional faces is influenced by individual's level of stress and anxiety. Valence unspecific affective processing is expected to be influenced by predictability of threat. Using a design of phasic fear (predictable threat), sustained anxiety (unpredictable threat) and safety (no threat), we investigated the magnetoencephalographic correlates and temporal dynamics of emotional face processing in a sample of phobic patients. Compared to non-anxious controls, phobic individuals revealed decreased parietal emotional attention processes during affective processing at mid-latency and late processing stages. While control subjects showed increasing parietal processing of the facial stimuli in line with decreasing threat predictability, phobic subjects revealed the opposite pattern. Decreasing threat predictability also led to increasing neural activity in the orbitofrontal and dorsolateral prefrontal cortex at mid-latency stages. Additionally, unpredictability of threat lead to higher subjective discomfort compared to predictability of threat and no threat safety condition. Our findings indicate that visual processing of emotional information is influenced by both stress induction and pathologic anxiety.


Assuntos
Mapeamento Encefálico , Expressão Facial , Medo/psicologia , Transtornos Fóbicos/complicações , Adulto , Análise de Variância , Animais , Feminino , Seguimentos , Humanos , Magnetoencefalografia , Masculino , Estimulação Luminosa , Valor Preditivo dos Testes , Escalas de Graduação Psiquiátrica , Aranhas , Adulto Jovem
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