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Stress and fear conditioning processes are both important vulnerability factors in the development of psychiatric disorders. In behavioral studies considerable sex differences in fear learning have been observed after increases of the stress hormone cortisol. But neuroimaging experiments, which give insights into the neurobiological correlates of stress × sex interactions in fear conditioning, are lacking so far. In the current functional magnetic resonance imaging (fMRI) study, we tested whether a psychosocial stressor (Trier Social Stress Test) compared to a control condition influenced subsequent fear conditioning in 48 men and 48 women taking oral contraceptives (OCs). One of two pictures of a geometrical figure was always paired (conditioned stimulus, CS+) or never paired (CS-) with an electrical stimulation (unconditioned stimulus). BOLD responses as well as skin conductance responses were assessed. Sex-independently, stress enhanced the CS+/CS- differentiation in the hippocampus in early acquisition but attenuated conditioned responses in the medial frontal cortex in late acquisition. In early acquisition, stress reduced the CS+/CS- differentiation in the nucleus accumbens in men, but enhanced it in OC women. In late acquisition, the same pattern (reduction in men, enhancement in OC women) was found in the amygdala as well as in the anterior cingulate. Thus, psychosocial stress impaired the neuronal correlates of fear learning and expression in men, but facilitated them in OC women. A sex-specific modulation of fear conditioning after stress might contribute to the divergent prevalence of men and women in developing psychiatric disorders.
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The present paper investigates the effects of age, sex, and cognitive factors on temporal-order perception. Nine temporal-order tasks were employed using two and four stimuli presented in the auditory and visual modalities. Significantly increased temporal-order thresholds (TOT) in the elderly were found for almost all tasks, while sex differences were only observed for two tasks. Multiple regression analyses show that the performance on most temporal-order tasks can be predicted by cognitive factors, such as speed of fluid reasoning, short-term memory, and attention. However, age was a significant predictor of TOT in three tasks using visual stimuli. We conclude (1) that age-related differences can often be attributed to cognitive factors involved in temporal-order perception, and (2) that the concept of temporal-order perception is more complex than implied by the current models.
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We examined whether males and females differ in the intensity and laterality of their hemodynamic responses towards visual disgust and fear stimuli. Forty-one female, and 51 male subjects viewed disgust-inducing, fear-inducing and neutral pictures in an fMRI block design. Self-report data indicated that the target emotions had been elicited successfully with women responding stronger than men. While viewing the fear pictures, which depicted attacks by humans or animals, men exhibited greater activation in the bilateral amygdala and the left fusiform gyrus than women. This response pattern may reflect greater attention from males to cues of aggression in their environment. Further, the lateralization of brain activation was comparable in the two genders during both aversive picture conditions.
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PURPOSE: The relationship between auditory temporal-order perception and phoneme discrimination has been discussed for several years, based on findings, showing that patients with cerebral damage in the left hemisphere and aphasia, as well as children with specific language impairments, show deficits in temporal-processing and phoneme discrimination. Over the last years several temporal-order measurement procedures and training batteries have been developed. However, there exists no standard diagnostic tool for adults that could be applied to patients with aphasia. Therefore, our study aimed at identifying a feasible, reliable and efficient measurement procedure to test for auditory-temporal processing in healthy young and elderly adults, which in a further step can be applied to patients with aphasia. METHODS: The tasks varied according to adaptive procedures (staircase vs. maximum-likelihood), stimuli (tones vs. clicks) and stimulation modes (binaural- vs. alternating monaural) respectively. A phoneme-discrimination task was also employed to assess the relationship between temporal and language processing. RESULTS: The results show that auditory temporal-order thresholds are stimulus dependent, age related, and influenced by gender. Furthermore, the cited relationship between temporal-order threshold and phoneme discrimination can only be confirmed for measurements with pairs of tones. CONCLUSION: Our results indicate, that different norms have to be established for different gender and age groups. Furthermore, temporal-order measurements with tones seem to be more suitable for clinical intervention studies than measurements with clicks, as they show higher re-test reliabilities, and only for measurements with tones an association with phoneme-discrimination abilities was found.
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Eintragsart
Sprache
- Englisch (4)
Thema
- *Sex Characteristics
- Acoustic Stimulation (1)
- Acoustic Stimulation/methods (1)
- Adult (3)
- Aged (2)
- Aged, 80 and over (1)
- Aging/*physiology (1)
- Aging/*psychology (1)
- alpha-Amylases/metabolism (1)
- Amygdala (1)
- Amygdala/anatomy & histology/blood supply/physiology (1)
- Analysis of Variance (1)
- Anterior cingulate (1)
- Attention/physiology (1)
- Auditory Perception/*physiology (1)
- Auditory Threshold/*physiology (1)
- Brain Mapping (2)
- Brain/physiology (1)
- *Cognition (1)
- Conditioning, Classical/*physiology (1)
- Cortisol (1)
- Discrimination, Psychological (1)
- Emotions/*physiology (1)
- Fear learning (1)
- Fear/*physiology (1)
- Fear/*physiology/*psychology (1)
- Female (4)
- fMRI (1)
- Galvanic Skin Response/physiology (1)
- Hemodynamics/*physiology (1)
- Humans (4)
- Hydrocortisone/metabolism (1)
- Likelihood Functions (1)
- Magnetic Resonance Imaging/methods (1)
- Male (4)
- Middle Aged (2)
- Nucleus accumbens (1)
- Oral contraceptives (1)
- Oxygen/blood (1)
- Photic Stimulation (2)
- Psychophysics/methods (1)
- Regression Analysis (1)
- Reproducibility of Results (1)
- Saliva/metabolism (1)
- Sex differences (1)
- Speech Discrimination Tests (1)
- Statistics, Nonparametric (1)
- Stress hormones (1)
- Stress, Psychological/*physiopathology/*psychology (1)
- *Time Perception (1)
- Time Perception/*physiology (1)
- TSST (1)
- Young Adult (1)