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Biology subjects

Ehlers, M. R.

Publications and source records attributed to Ehlers, M. R..

4 recordsLinked to original sources

Anxiety-Related Traits Are Associated with Subjective Biases but not Altered Threat-Safety Discrimination

Anxiety-related traits (ARTs) have been linked to altered fear learning, but previous studies have typically examined different experimental phases and response systems, limiting the comparability of findings and the accumulation of consistent evidence. Here, we comprehensively examined associations between ARTs and fear conditioning across acquisition, extinction and renewal and across subjective, physiological and neural response systems in a well-powered sample (N = 267) using a two-day differential conditioning paradigm. ARTs were operationalized as a composite of trait anxiety, neuroticism, and intolerance of uncertainty and conditioned responding was assessed using skin conductance responses, fear-potentiated startle, US expectancy ratings, fear ratings, and functional magnetic resonance imaging. Higher ARTs were consistently associated with elevated subjective fear and US expectancy to both threat and safety cues during extinction and renewal, without corresponding elevations in physiological responding. At the same time, ARTs were not associated with threat-safety discrimination in subjective or physiological measures across phases, while neural associations were limited to reduced dorsal anterior cingulate cortex discrimination during early renewal. These findings suggest that ARTs are characterized by a CS unspecific cognitive bias toward heightened threat expectancy and evaluation rather than altered associative fear learning, highlighting the importance of distinguishing conditioned discrimination from general levels of responding across response systems.

neuroscience↗

Robust group- but limited individual-level (longitudinal) reliability and insights into cross-phases response prediction of conditioned fear

Here we follow the call to target measurement reliability as a key prerequisite for individual-level predictions in translational neuroscience by investigating i) longitudinal reliability at the individual and ii) group level, iii) cross-sectional reliability and iv) response predictability across experimental phases. 120 individuals performed a fear conditioning paradigm twice six month apart. Analyses of skin conductance responses, fear ratings and BOLD-fMRI with different data transformations and included numbers of trials were conducted. While longitudinal reliability was generally poor to moderate at the individual level, it was good for acquisition but not extinction at the group-level. Cross-sectional reliability was satisfactory. Higher responding in preceding phases predicted higher responding in subsequent experimental phases at a weak to moderate level depending on data specifications. In sum, the results suggest the feasibility of individual-level predictions for (very) short time intervals (e.g., cross-phases) while predictions for longer time intervals may be problematic.

neuroscience↗

Reactivation of hedonic but not sensory representations in human emotional learning

Learning which stimuli in our environment co-occur with painful or pleasurable events is critical for survival. Previous research has established the basic neural and behavioural mechanisms of aversive and appetitive conditioning; however, it is unclear what precisely is learned. Here we examined what aspects of the unconditioned stimulus (US) - sensory and hedonic - are transferred to the conditioned stimulus (CS). To decode the content of brain activation patterns elicited during appetitive (soft touch) and aversive (painful touch) conditioning of faces, a novel variation of representational similarity analysis (RSA) based on theoretically driven representational patterns of interest (POIs) was applied to fMRI data. Once face associations were learned through conditioning, globally the CS reactivated US representational patterns showing conditioning-dependent reactivation. More specifically, in higher order brain regions, the CS only reactivated hedonic but not sensory aspects of the US - suggesting that affective conditioning primarily carries forward the valence of the experience rather than its sensory origins.

neuroscience↗

Hedonic representations in primary somatosensory cortices; Pain but not pleasure?

Emotion is typically understood to be an internal subjective experience originating in the brain. Yet in the somatosensory system hedonic information is coded by mechanoreceptors at the point of sensory contact before it reaches the central nervous system. It remains unknown, however, how these distinct peripheral channels for tactile hedonic information contribute to representations of interoceptive states relative to exteroceptive experience. In this fMRI study we applied representational similarity analyses with pattern component modeling, a technique that deconstructs representational states into a weighted set of distinct predefined constructs, to dissociate how discriminatory vs. hedonic tactile information, carried by A- and C-/CT-fibers respectively, contributes to population code representations in the human brain. Results demonstrated that information about appetitive and aversive tactile sensation is represented separately from non-hedonic tactile information across cortical structures. Specifically, although hedonic touch originates as a peripheral signal, labeled at the point of contact, representations in somatosensory cortices are guided by experiences of non-hedonic touch, By contrast, representations in regions associated with interoception and affect encode signals of hedonic touch. This provides evidence of complex tactile encoding that involves both external-exteroceptive and internal-interoceptive dimensions. Importantly, hedonic touch contributes to representations of internal state as well as those of externally generated stimulation.

neuroscience↗