Biology subjects

Schmitt, O.

Publications and source records attributed to Schmitt, O..

4 recordsLinked to original sources

bioRxiv2025

Pigs' brain responses to stroking after long-term positive human interactions: An fMRI exploratory study

Positive interactions with humans can induce pleasurable experiences in animals, but their underlying neurobiology mechanisms are unknown. We investigated the brain responses (Functional Magnetic Resonance Imaging) to stroking by a human in 20 pigs under general anaesthesia. Ten pigs received positive human contacts over 9 weeks post-weaning (POS) and 10 pigs did not (CTL). Images from CTL pigs showed peaks of activation in the primary somatosensory cortex, caudate nucleus, anterior prefrontal cortex, and dorsal anterior cingulate cortex during stroking. Greater peaks of activation in the anterior prefrontal, ventral anterior cingulate, primary somatosensory and somatosensory association cortices were observed in POS pigs; whereas greater peaks of activation in the amygdala were observed in CTL pigs. Therefore, stroking is perceived and possibly elicited positive emotions in anesthetised pigs, and it may be perceived as more pleasant by experienced pigs than naive pigs, which may rather perceive it as a novel stimulus. Highlights- The brain of anaesthetised pigs can perceive tactile stimuli - Stroking by humans is a pleasurable experience for pigs - Experience with positive contacts enhances signs of positive perception of stroking

neuroscience↗

bioRxiv2025

The inner dynamics of positive human-animal interactions: investigating the roles of oxytocin, opioids, dopamine, serotonin and the proteome

Research on the neuroendocrine basis of positive interactions has predominantly focused on oxytocin (OT), although dopamine (DA) and opioids also play crucial roles. Furthermore, these neurotransmitters are known to interact with each other but have seldom been studied concurrently. In this study, we quantified longitudinal changes in these neurotransmitters using a within-subject, 2 x 2 factorial design by varying human familiarity (familiar versus unfamiliar) and contact type (positive contacts versus ignoring) for 10 min human-pig interaction sessions. We repeatedly sampled cerebrospinal fluid from 10 pigs through a spinal catheter 65 and 5 min before the test and at 10, 30, 60, 120 and 240 min after the start of the test. Samples at various timepoints were analysed for OT, DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), {beta}-endorphin opioids concentrations, and using proteomics to explore novel protein candidates. The test condition (human familiarity x contact type) had a significant effect on the concentration of {beta}-endorphin (F1,118.59 = 4.45; P = 0.04) and 5-HIAA (F1,73.47 = 5.02; P = 0.03), and tended to affect the concentration of oxytocin (F1, 119.8 = 3.19; P = 0.08) and DOPAC (F1,70.57 = 3.31; P = 0.07), but pair-wise comparisons were not significant. There was only a minor effect on the pigs behaviour, which suggests that the test conditions may have had limited effect. Nevertheless, this approach provides a valuable method to study neurotransmitter changes over time and simultaneously. Highlights- Oxytocin was higher when pigs were ignored than when they had positive contacts - Oxytocin was highest in the novel condition of an unfamiliar human ignoring the pig - Human familiarity and contact type affected {beta}-endorphin and 5-HIAA concentrations - Dopamine metabolites and the proteome were not affected by the test conditions

animal behavior and cognition↗

bioRxiv2023

Connectome-based prediction of functional impairment in experimental stroke models

Experimental rat models of stroke and hemorrhage are important tools to investigate cerebrovascular disease pathophysi- ology mechanisms, yet how significant patterns of functional impairment induced in various models of stroke are related to changes in connectivity at the level of neuronal populations and mesoscopic parcellations of rat brains remain unresolved. To address this gap in knowledge, we employed two middle cerebral artery occlusion models and one intracerebral hemorrhage model with variant extent and location of neuronal dysfunction. Motor and spatial memory function was assessed and the level of hippocampal activation via Fos immunohistochemistry. Contribution of connectivity change to functional impairment was analyzed for connection similarities, graph distances and spatial distances as well as the importance of regions in terms of network architecture based on the neuroVIISAS rat connectome. We found that functional impairment correlated with not only the extent but also the locations of the injury among the models. In addition, via coactivation analysis in dynamic rat brain models, we found that lesioned regions led to stronger coactivations with motor function and spatial learning regions than with other unaffected regions of the connectome. Dynamic modeling with the weighted bilateral connectome detected changes in signal propagation in the remote hippocampus in all 3 stroke types, predicting the extent of hippocampal hypoactivation and impairment in spatial learning and memory function. Our study provides a comprehensive analytical framework in predictive identification of remote regions not directly altered by stroke events and their functional implication.

neuroscience↗

bioRxiv2019

Distinct structure-function relationships across cortical regions and connectivity scales in the rat brain

An improved understanding of the structure-function relationship in the brain is necessary to know to what degree structural connectivity underpins abnormal functional connectivity seen in many disorders. We integrated high-field resting-state fMRI-based functional connectivity with high-resolution macro-scale diffusion-based and meso-scale neuronal tracer-based structural connectivity, to obtain an accurate depiction of the structure-function relationship in the rat brain. Our main goal was to identify to what extent structural and functional connectivity strengths are correlated, macro- and meso-scopically, across the cortex. Correlation analyses revealed a positive correspondence between functional connectivity and macro-scale diffusion-based structural connectivity, but no correspondence between functional connectivity and meso-scale neuronal tracer-based structural connectivity. Locally, strong functional connectivity was found in two well-known resting-state networks: the sensorimotor and default mode network. Strong functional connectivity within these networks coincided with strong short-range intrahemispheric structural connectivity, but with weak heterotopic interhemispheric and long-range intrahemispheric structural connectivity. Our study indicates the importance of combining measures of connectivity at distinct hierarchical levels to accurately determine connectivity across networks in the healthy and diseased brain. Distinct structure-function relationships across the brain can explain the organization of networks and may underlie variations in the impact of structural damage on functional networks and behavior.

neuroscience↗