Biology subjects

Hinz, J.

Publications and source records attributed to Hinz, J..

5 recordsLinked to original sources

bioRxiv2026

A Comprehensive Database of Simulations and Meshes of Coronary Arteries from the Fame 2 Trial

AO_SCPLOWBSTRACTC_SCPLOWIn this work, we publish the 3D unsteady Navier-Stokes numerical simulations and meshes of coronary arteries reconstructed from invasive X-ray coronary angiograms acquired during in the Fractional Flow Reserve versus Angiography for Multivessel Evaluation 2 (FAME 2) trial. Out of the 914 clinical images, 779 vessels are successfully reconstructed and meshed. The remaining 135 vessels have been discarded since they exhibited self-intersecting geometry during the reconstruction process. The meshes are hexahedral and all of them have the same number of vertices and identical connectivity; their high quality is demonstrated using standard mesh quality indices. The simulations are performed using the Finite Element Method (FEM) with state-of-the-art coronary boundary conditions applied at the outlet. The motivation behind this effort relies from the scarcity of publicly available numerical haemodynamics data, despite the growing interest in data-driven modeling and machine learning techniques. The database is available at the link: https://doi.org/10.7910/DVN/GPCUNS

bioinformatics↗

bioRxiv2024

Neural mechanisms of adaptive value coding in the amygdala

To address their needs, animals must optimize behavior by integrating external cues with internal state signals, such as hunger or thirst, environmental conditions, and past experiences. Accordingly, the perceived value of a reward varies depending on an animals current needs. Updating the specific value of rewards predicted by external cues depends on the basolateral amygdala (BLA). However, neurophysiological investigations have centered around the assumption of stimulus-invariant value representations and have not been able to account for behavioral findings that support the BLAs ability to represent stimulus-specific value of distinct appetitive or aversive outcomes. To address how the BLA encodes and updates stimulus-specific value representations, we exposed head-fixed mice to distinct sets of gustatory rewards while tracking perceived value using lick microstructural analysis. Two-photon calcium imaging of BLA principal neurons revealed that the magnitude of the BLA population response scaled with perceived reward value and that the values of different rewards were encoded by distinct neuronal subpopulations. Moreover, reward representations rapidly re-scaled when mice were exposed to a reward that was larger than all previous rewards. Finally, value representations depended on an animals internal state as thirst selectively increased the responses to water rewards whereas aversive experiences strongly attenuated responses to sucrose. Our findings demonstrate that value representations in the BLA are stimulus-specific and highly adaptive to account for changes in relative reward value and to reflect an animals current affective and homeostatic state. This mechanism enables sensory-specific value updates necessary for state-adapted decision making and learning.

neuroscience↗

bioRxiv2020

Reduction of visual stimulus artifacts using a spherical tank for small, aquatic animals

Delivering appropriate stimuli remains a challenge in vision research, particularly for aquatic animals such as zebrafish. Due to the shape of the water tank and the associated optical paths of light rays, the stimulus can be subject to unwanted refraction or reflection artifacts, which may spoil the experiment and result in wrong conclusions. Here, we employ computer graphics simulations and calcium imaging in the zebrafish optic tectum to show, how a spherical glass container optically outperforms many previously used water containers, including Petri dish lids. We demonstrate that aquatic vision experiments suffering from total internal reflection artifacts at the water surface or at the flat container bottom may result in the erroneous detection of visual neurons with bipartite receptive fields and in the apparent absence of neurons selective for vertical motion. Our results and demonstrations will help aquatic vision neuroscientists on optimizing their stimulation setups.

neuroscience↗

bioRxiv2019

Spherical arena reveals optokinetic response tuning to stimulus location, size and frequency across entire visual field of larval zebrafish

Many animals have large visual fields, and sensory circuits may sample those regions of visual space most relevant to behaviours such as gaze stabilisation and hunting. Despite this, relatively small displays are often used in vision neuroscience. To sample stimulus locations across most of the visual field, we built a spherical stimulus arena with 14,848 independently controllable LEDs, measured the optokinetic response gain of immobilised zebrafish larvae, and related behaviour to previously published retinal photoreceptor densities. We measured tuning to steradian stimulus size and spatial frequency, and show it to be independent of visual field position. However, zebrafish react most strongly and consistently to lateral, nearly equatorial stimuli, consistent with previously reported higher spatial densities in the central retina of red, green and blue photoreceptors. Upside-down experiments suggest further extra-retinal processing. Our results demonstrate that motion vision circuits in zebrafish are anisotropic, and preferentially monitor areas with putative behavioural relevance. Author summaryThe visual system of larval zebrafish mirrors many features present in the visual system of other vertebrates, including its ability to mediate optomotor and optokinetic behaviour. Although the presence of such behaviours and some of the underlying neural correlates have been firmly established, previous experiments did not consider the large visual field of zebrafish, which covers more than 160{degrees} for each eye. Given that different parts of the visual field likely carry unequal amount of behaviourally relevant information for the animal, this raises the question whether optic flow is integrated across the entire visual field or just parts of it, and how this shapes behaviour such as the optokinetic response. We constructed a spherical LED arena to present visual stimuli almost anywhere across their visual field, while tracking horizontal eye movements. By displaying moving gratings on this LED arena, we demonstrate that the optokinetic response, one of the most prominent visually induced behaviours of zebrafish, indeed strongly depends on stimulus location and stimulus size, as well as on other parameters such as the spatial and temporal frequency of the gratings. This location dependence is consistent with areas of high retinal photoreceptor densities, though evidence suggests further extraretinal processing.

neuroscience↗

bioRxiv2019

Parallel channels for motion feature extraction in the pretectum and tectum of larval zebrafish

Non-cortical visual areas in vertebrate brains extract different stimulus features, such as motion, object size and location, to support behavioural tasks. The optic tectum and pretectum, two primary visual areas, are thought to fulfil complementary biological functions in zebrafish to support prey capture and optomotor stabilisation behaviour. However, the adaptations of these brain areas to behaviourally relevant stimulus statistics are unknown. Here, we used calcium imaging to characterize the receptive fields of 1,926 motion-sensitive neurons in diencephalon and midbrain. We show that many caudal pretectal neurons have large receptive fields (RFs), whereas RFs of tectal neurons are smaller and mostly size-selective. RF centres of large-size RF neurons in the pretectum are predominantly located in the lower visual field, while tectal neurons sample the upper-nasal visual field more densely. This tectal visual field sampling matches the expected prey item locations, suggesting that the tectal magnification of the upper-nasal visual field might be an adaptation to hunting behaviour. Finally, we probed optomotor responsiveness and found that even relatively small stimuli drive optomotor swimming, if presented in the lower-temporal visual field, suggesting that the pretectum preferably samples information from this region on the ground to inform optomotor behaviour. Our characterization of the parallel processing channels for non-cortical motion feature extraction provides a basis for further investigation into the sensorimotor transformations of the zebrafish brain and its adaptations to habitat and lifestyle.

neuroscience↗