Accumulating evidence suggests that the magnetic resonance imaging (MRI) scanner can act as a stressor, eliciting subjective and neuroendocrine stress responses. Approaches to familiarize subjects with the scanner could help minimizing unintended effects on neural activation patterns of interest. Controlled studies on the effects of a scanner training are however missing. Using a comparative design, we analyzed within- and between session changes in subjective and neuroendocrine stress parameters in 63 healthy, scanner-naïve adults who participated in a two-day training protocol in an MRI, mock, or lab environment. A habituation task was used to assess within-session changes in subjective and neuroendocrine (cortisol) stress parameters; between-session changes were indicated by differences between days. MRI and mock, but not lab training were successful in reducing subjective distress towards the scanner. In contrast, cortisol reactivity towards the training environment generally increased during day 2, and the percentage of cortisol responders particularly rose in the mock and MRI groups. Within-session habituation of subjective arousal and anxiety was observed during both days and irrespective of training condition. Present findings demonstrate that training in a scanner environment successfully reduces subjective distress, but may also induce sensitization of endocrine stress levels during repeated scanning. Subjective distress can further be stabilized by acclimating subjects to the environment prior to the MRI assessment, including a short habituation phase into the assessment protocol. If replicated, present findings should be considered by researchers employing repeated measurement designs where subjects are exposed to a scanner more than once.

An association between inflammation and mood deterioration has been proposed as a potential explanatory mechanism underlying many pathologies. Previous research attributes this consistently reoccurring connection between inflammation and psychopathology that is often reported within the literature, to a relationship between the HPA axis, the body’s stress response system and the immune system. There is evidence of a bidirectional feedback loop between end-products of the immune system and the HPA-axis such as cytokines and cortisol. This is supported by research reporting that components of subjective well-being such as positive affect, optimism and life satisfaction can produce beneficial health outcomes by potentially targeting this feedback loop. The present longitudinal study tested if higher positive affect independently corresponds to lower levels of inflammatory markers Interleukin-6 (IL-6) and C-reactive protein (CRP) and HPA axis marker cortisol. The study further tested if higher subjective well-being decreases levels of IL-6 and CRP as well as cortisol. The study employed a subsample of participants from the Midlife in Japan (MIDJA) Biomarker project (n=174) that underwent testing at two separate time points across a period of 4 years. The data included subjective well-being, positive affect, IL-6, CRP, cortisol, perceived stress, neuroticism and demographic variables. Positive affect was not associated with any inflammatory marker or cortisol. Subjective well-being had no effect on CRP but reduced IL-6 and cortisol even when controlling for all control and demographic variables. It is concluded that subjective well-being may be linked to lower inflammation and HPA axis activity. / Ett samband mellan inflammation och sjukdomsbeteende har föreslagits som en förklaringsmekanism bakom förekomsten av många patologier. Den konsekventa anknytningen mellan inflammation och psykopatologi som många tidigare studier demonstrerat innebär ett samband mellan immunsystemet och HPA-axeln som är den struktur som utgör kroppens svar på stressorer. Det finns tecken på en återkopplingsslinga mellan slutprodukter av det immunologiska systemet och HPA-axeln såsom cytokiner och kortisol. Detta har stöd i tidigare forskning som rapporterat att komponenter av subjektivt välbefinnande så som positiv affekt, optimism och livstillfredställelse kan medföra positiva hälsoutfall genom att potentiellt influera denna återkopplingsslinga. Förevarande longitudinella studie testar om högre positiv affekt leder till lägre nivåer av de inflammatoriska markörerna interleukin-6 (IL-6) och C-reaktivt protein (CRP) samt HPA-axel markören kortisol. Studien testar vidare även om högre subjektivt välbefinnande leder till lägre nivåer av IL-6, CRP och kortisol. Deltagarna är ett subsampel från Biomarkerprojektet (n = 174) inom Midlife in Japan (MIDJA) som genomgick testning vid två separata tidpunkter över en period av 4 år. Data består av subjektivt välbefinnande, positiv affekt, IL-6, CRP, kortisol, upplevd stress, neuroticism samt demografiska variabler. Positiv affekt hade ingen signifikant effekt på någon av de inflammatoriska markörerna eller kortisol. Subjektivt välbefinnande hade inte någon signifikant effekt på CRP men reducerade signifikant IL-6 och kortisol och dessa effekter förblev signifikanta efter kontroll för samtliga kontroll och demografiska variabler. Följaktligen dras slutsatsen att subjektivt välbefinnande kan leda till lägre inflammation och HPA-axel aktivitet.

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16-androstenes Anosmia in Men 16-androstens are compounds of steroid character which are secreted to the skin as part of apocrine glands secrets and they participate in creating body odor. It was found that androstenes influence affective state and psychophysiological reactions. The effect of androstenes can be also found on subliminal level. However, it has not yet been tested whether individuals with specific anosmia could also be influenced this way. Specific anosmia is described as an individual's incapability of conscious detection of particular odor while the detection of other compounds remains unaffected. The aim of the thesis is to test whether specifically anosmic individuals can be influenced by compounds to which they are anosmic to. This hypothesis is based on research of sensitization. Previous research indicates that olfactory perception may be of larger plasticity than thought. The theoretical part focuses on critical analysis of androstenes and research on specific anosmia. This field contains topics such as influence of chemical structure on androstenes perception, genetic influences, sensitization, functions of androstenes in interpersonal interactions and research on brain imagining. The experimental part focused on measuring subjective ratings of mood and psychophysiological...