Biology subjects

van Oudenhove, L.

Publications and source records attributed to van Oudenhove, L..

3 recordsLinked to original sources

bioRxiv2023

Overnight fasting facilitates safety learning by changing the neurophysiological response to relief from threat omission

Excessive avoidance and slow extinction of fear are hallmarks of anxiety disorders. We have previously found that overnight fasting diminishes excessive avoidance and speeds up fear extinction by decreasing subjective relief during threat omissions. Since relief tracks the reward prediction error signal that governs safety learning, we hypothesized that these effects of fasting might be linked to a decreased activation in brain regions related to reward prediction error processing. Hence, we replicated our previous study in a 3T-MRI scanner. Overnight fasting increased effective avoidance and sped up fear extinction learning. During extinction, the fasting group showed lower activations in the ventromedial prefrontal cortex and nucleus accumbens in response to threat omissions signaled by a safe cue. Nucleus accumbens activations were modulated by relief in the control group. This study provides support for overnight fasting as an adjunct to treatments for anxiety, but the effects should be investigated in anxious patients.

neuroscience↗

bioRxiv2022

Non-target effects of ten essential oils on the egg-parasitoid Trichogramma evanescens

Essential oils (EOs) are increasingly used as biopesticides due to their insecticidal potential. This study addresses their non-target effects on a biological control agent: the egg parasitoid Trichogramma evanescens. In particular, we tested whether EOs affected parasitoid fitness either directly, by decreasing pre-imaginal survival, or indirectly, by disrupting parasitoids orientation abilities. The effect of Anise, Fennel, Sweet orange, Basil, Coriander, Oregano, Peppermint, Mugwort, Rosemary and Thyme EOs were studied on five strains of T. evanescens. Specific experimental setups were developed, and data obtained from image analysis were interpreted with phenomenological models fitted with Bayesian inference. Results highlight the fumigant toxicity of EOs on parasitoid development. Anise, Fennel, Basil, Coriander, Oregano, Peppermint and Thyme EOs are particularly toxic and drastically reduce the emergence rate of T. evanescens. Most EOs also affect parasitoid behavior: (i) Basil, Coriander, Oregano, Peppermint, Mugwort and Thyme EOs are highly repellent for naive female parasitoids; (ii) Anise and Fennel EOs can have repellent or attractive effects depending on strains; and (iii) Sweet orange, Oregano and Rosemary EOs have no detectable impact on orientation behavior. This study shows that EOs fumigation have non-target effects on egg parasitoids. This highlights the need to cautiously precise the deployment framework of biopesticides in an agroecological perspective.

ecology↗

bioRxiv2020

The Brain Activation-based Sexual Image Classifier (BASIC): A sensitive and specific fMRI activity pattern for sexual image perception

Sexual stimuli processing is a key element in the repertoire of human affective and motivational states. Previous neuroimaging studies of sexual stimulus processing have revealed a complicated mosaic of activated regions, leaving unresolved questions about their sensitivity and specificity to sexual stimuli per se, generalizability across individuals, and potential utility as neuromarkers for sexual stimulus processing. In this study, data on sexual, negative, non-sexual positive, and neutral images from Wehrum et al. (2013) (N = 100) were re-analyzed with multivariate Support Vector Machine models to create the Brain Activation-based Sexual Image Classifier (BASIC) model. This model was tested for sensitivity, specificity, and generalizability in cross-validation (N = 100) and an independent test cohort (N = 18; Kragel et al. 2019). The BASIC model showed highly accurate performance (94-100%) in classifying sexual versus neutral or nonsexual affective images in both datasets. Virtual lesions and test of individual large-scale networks (e.g., visual or attention networks) show that these individual networks are neither necessary nor sufficient to capture sexual stimulus processing. These findings suggest that brain responses to sexual stimuli constitute a category of mental event that is distinct from general affect and involves multiple brain networks. It is, however, largely conserved across individuals, permitting the development of neuromarkers for sexual processing in individual persons. Future studies could assess performance of BASIC to a broader array of affective/motivational stimuli and link brain responses with physiological and subjective measures of sexual arousal.

neuroscience↗