Biology subjects

Kronbichler, M.

Publications and source records attributed to Kronbichler, M..

6 recordsLinked to original sources

bioRxiv2026

Dimensional and Categorical Predictors of Theory of Mind Network Activation: A transdiagnostic fMRI Study in Psychiatric Inpatients

Socio-cognitive alterations are widely observed across different psychiatric conditions, yet it remains unclear whether these deficits map onto distinct diagnostic categories or represent a shared transdiagnostic phenotype, driven by dimensional psychopathological symptom severity.This study evaluates Theory of Mind (ToM) network activation during a naturalistic functional magnetic resonance imaging (fMRI) movie paradigm in 313 participants, including 91 healthy controls and 222 psychiatric inpatients across five distinct diagnostic clusters (substance use, schizophrenia spectrum, affective, anxiety, and personality disorders). Frequentist analyses revealed decreased ToM-selective activity in psychiatric patients, compared to controls across all ToM regions of interest (ROIs). No significant difference emerged between diagnostic groups, but ROI activation correlated negatively with Adult Self-Report (ASR) scales (Total Problems, Internalising, Externalising). Subsequent Bayesian analysis of covariance (ANCOVAs) consistently favoured models that excluded traditional categorical diagnoses, suggesting that dimensional measures, especially Total Problems and Internalising, provided substantially greater predictive utility for ToM-related regional brain activation. Our findings challenge traditional categorical classifications in neurobiological research as they suggest that atypical mentalising might reflect a shared transdiagnostic vulnerability.

neuroscience↗

bioRxiv2022

Evaluating the capabilities and challenges of layer-fMRI VASO at 3T

Sub-millimeter functional imaging has the potential to capture cortical layer-specific functional information flow within and across brain systems. Recent sequence advancements of fMRI signal readout and contrast generations resulted in wide adaptation of layer-fMRI protocols across the global ultra-high-field (UHF) neuroimaging community. However, most layer-fMRI applications are confined to one of {approx}100 privileged UHF imaging centers, and sequence contrasts with unwanted sensitivity to large draining veins. In this work, we propose the application of vein-signal free vascular space occupancy (VASO) layerfMRI sequences at widely accessible 3T scanners. Specifically, we implement, characterize, and apply a cerebral blood volume (CBV)-sensitive VASO fMRI at a 3T scanner setup, as it is typically used in the majority of cognitive neuroscience and clinical neuroscience fMRI studies. We find that the longer [Formula], and stronger relative T1 contrast at 3T can account for some of the lower z-magnetization in the inversion-recovery VASO sequence compared to 7T and 9.4T. In the main series of experiments (N=16), we test the utility of this setup for motor tasks and find that-while being limited by thermal noise-3T layer-fMRI VASO is feasible within conventional scan durations. In a series of auxiliary studies, we furthermore explore the generalizability of the developed layer-fMRI protocols for a larger range of study designs including: visual stimulation, whole brain movie watching paradigms, and cognitive tasks with weaker effect sizes. We hope that the developed imaging protocols will help to increase accessibility of vein-signal free layer-fMRI imaging tools to a wider community of neuroimaging centers. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=179 SRC="FIGDIR/small/501554v1_ufig1.gif" ALT="Figure 1"> View larger version (66K): org.highwire.dtl.DTLVardef@1b2c6b5org.highwire.dtl.DTLVardef@139b13org.highwire.dtl.DTLVardef@129ff82org.highwire.dtl.DTLVardef@45e9d8_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Intrinsic Neural Timescales in Autism Spectrum Disorder and Schizophrenia. A Replication and Direct Comparison Study

Intrinsic neural timescales (INT) reflect the duration for which brain areas store information. A posterior - anterior hierarchy of increasingly longer INT has been revealed in both typically developed individuals (TD), as well as patients diagnosed with autism spectrum disorder (ASD) and schizophrenia (SZ), though INT are, overall, shorter in both patient groups. In the present study, we attempted to replicate previously reported group differences by comparing INT of TD to ASD and SZ. We replicated the previously reported result showing reduced INT in the left lateral occipital gyrus and the right post-central gyrus in SZ compared to TD. For the first time, we also directly compared the INT of the two patient groups and found that these same two areas show significantly reduced INT in SZ compared to ASD. In ASD, significant correlations were found between INT and their clinical and phenotypic characteristics. Our results point to the left lateral occipital gyrus and the right post-central gyrus as holding potential for further diagnostic refinement of SZ.

neuroscience↗

bioRxiv2019

Age-related changes in human emotional egocentricity: evidence from multi-level neuroimaging

Emotional egocentric bias (EEB) occurs when, due to a partial failure in self-other distinction, empathy for anothers emotions is influenced by our own emotional state. Recent studies have demonstrated that this bias is higher in children, adolescents and older adults than in young adults. In the latter, overcoming emotional egocentrism has been associated with significant activity in the right supramarginal gyrus (rSMG), as well as increased connectivity between rSGM and somatosensory and visual cortices. Investigations on the neural correlates of EEB in adolescents and older adults are missing. We filled this gap, by asking female participants from three different age groups (adolescents, young adults and older adults, N=92) to perform a well-validated EEB task (Silani et al., 2013) in an MRI scanner. A multi-level analysis approach of MRI data including functional segregation, effective connectivity and structural analyses was adopted. Results revealed higher EEB in older compared to young adults and a comparable EEB in adolescents and young adults. Age-related differences in EEB were associated with differences in task-related rSMG connectivity with somatosensory cortices, especially with S2, which acted as a partial mediator between age and EEB. These findings provide further evidence for the crucial role of the rSMG in self-other distinction in the emotional domain, and suggest that the age-related decline in overcoming EEB is best explained by changes in rSMG connectivity rather than decreased regional activity in that area. This advocates a more systematic investigation of task-related connectivity in studies on aging and life-span development of social-cognitive phenomena.\n\nSignificance StatementEmpathy comprises both the ability to identify and share anothers emotional state, and the ability to disentangle ones own from the others emotional state. When self- and other-related emotions are conflicting, empathy might be negatively influenced by egocentric tendencies. This phenomenon is referred to as emotional egocentric bias (EEB), with previous research showing that its extent changes across the life-span. Here, we provide evidence that age-related differences in EEB are mainly associated with age-related changes in rSMG effective connectivity, and in particular that higher EEB in older adults is associated to lower rSMG effective connectivity with somatosensory cortices. These findings suggest the importance, particularly in aging, of intact functional connectivity for optimal socio-cognitive functioning.

neuroscience↗

bioRxiv2019

Basal forebrain volume selectively and reliably predicts the cortical spread of Alzheimer’s degeneration

Alzheimers disease neuropathology is thought to spread across anatomically and functionally connected brain regions. However, the precise sequence of spread remains ambiguous. The prevailing model posits that Alzheimers neurodegeneration starts in the entorhinal cortices, before spreading to temporoparietal cortex. Challenging this model, we previously provided evidence that degeneration within the nucleus basalis of Meynert (NbM), a subregion of the basal forebrain heavily populated by cortically projecting cholinergic neurons, precedes and predicts entorhinal degeneration (Schmitz and Spreng, 2016). There have been few systematic attempts at directly comparing staging models using in vivo longitudinal biomarker data, and determining if these comparisons generalize across independent samples. Here we addressed the sequence of pathological staging in Alzheimers disease using two independent samples of the Alzheimers Disease Neuroimaging Initiative (N1 = 284; N2 = 553) with harmonized CSF assays of amyloid (A{beta}) and hyperphosphorylated tau (pTau), and longitudinal structural MRI data over two years. We derived measures of gray matter degeneration in a priori NbM and the entorhinal regions of interest. To examine the spreading of degeneration, we used a predictive modelling strategy which tests whether baseline gray matter volume in a seed region accounts for longitudinal change in a target region. We demonstrated that predictive pathological spread favored the NbM[->]entorhinal over the entorhinal[->]NbM model. This evidence generalized across the independent samples (N1: r=0.20, p=0.03; N2: r=0.37, p<0.001). We also showed that CSF concentrations of pTau/A{beta} moderated the observed predictive relationship, consistent with evidence in rodent models of an underlying trans-synaptic mechanism of pathophysiological spread (t826=2.55, p=0.01). The moderating effect of CSF was robust to additional factors, including clinical diagnosis (t826=1.65, p=0.49). We then applied our predictive modelling strategy to an exploratory whole-brain voxel-wise analysis to examine the spatial specificity of the NbM[->]entorhinal model. We found that smaller baseline NbM volumes predicted greater degeneration in localized regions of the entorhinal and perirhinal cortices. By contrast, smaller baseline entorhinal volumes predicted degeneration in the medial temporal cortex, recapitulating the prevailing staging model. Our findings suggest that degeneration of the basal forebrain cholinergic projection system is a robust and reliable upstream event of entorhinal and neocortical degeneration, calling into question the prevailing view of Alzheimers disease pathogenesis.

neuroscience↗

bioRxiv2018

Computational mechanisms of curiosity and goal-directed exploration

Successful behaviour depends on the right balance between maximising reward and soliciting information about the world. Here, we show how different types of information-gain emerge when casting behaviour as surprise minimisation. We present two distinct mechanisms for goal-directed exploration that express separable profiles of active sampling to reduce uncertainty. Hidden state exploration motivates agents to sample unambiguous observations to accurately infer the (hidden) state of the world. Conversely, model parameter exploration, compels agents to sample outcomes associated with high uncertainty, if they are informative for their representation of the task structure. We illustrate the emergence of these types of information-gain, termed active inference and active learning, and show how these forms of exploration induce distinct patterns of Bayes-optimal behaviour. Our findings provide a computational framework to understand how distinct levels of uncertainty induce different modes of information-gain in decision-making.

neuroscience↗