Monday, April 14th, 2025

Time	Event
10:50a	Compression of functional gradients from rest to naturalistic processing: Moderation effect of age The functional cortical hierarchy of the human brain, a fundamental principle of brain organization, has been extensively characterized during resting state for healthy younger adults. However, functional re-organization during naturalistic settings, such as movie-watching, and its alterations across the adult lifespan remains poorly understood. Using resting-state and movie fMRI data from two large datasets, Cam-CAN (N=416) and DyNAMiC (N=156), this study conducted a comprehensive comparison of brain organization across two states. We identified a robust reorganization with compression of functional gradients from rest to movie-watching states, which is mediated by changes in functional integration and segregation of brain networks. The extent of compression from rest to movie was significantly greater in older adults and predicted worse cognitive performance among the elderly population. Our findings provide novel insights into how macroscale brain hierarchy is reorganized during naturalistic processing, and how this reorganization during aging impacts cognitive processes, offering a deeper understanding of the neural basis of aging and cognition. (Comment on this)
5:18p	Mechanisms of long term non-reinforced preference change: functional connectivity changes in a longitudinal functional MRI study Behavioral change studies mostly focus on external reinforcements to modify preferences. Cue-approach training (CAT) is a paradigm that influences preferences by the mere association of stimuli, sensory cues, and a rapid motor response, without external reinforcements. The behavioral effect has been shown to last for months after less than one hour of training. Here, we used a modified version of CAT by changing the neutral-cue to a number that represented a monetary amount of reward that the participants accumulate (i.e. incentive-cue). After a single training session, we compared behavioral performance and functional connectivity (FC), as measured using functional magnetic resonance imaging, between two groups, one receiving a neutral-cue and the other receiving an incentive-cue, at 5 time points across one year. We replicated the maintenance of behavioral changes after 6-months for the non-reinforced neutral-cue participants, but not for the reinforced group. The reinforced training group showed higher FC within the limbic system, whereas the non-externally reinforced group showed higher functional connectivity within and between default-mode and dorsal-attention networks. Our findings offer putative neural correlates for both reinforced and non-reinforced preference changes that are maintained over time and which could be implemented in future behavioral change interventions. (Comment on this)
5:18p	A mouse model of early sporadic tau pathology induces neurogenic plasticity in the hippocampus Alzheimers disease is characterized by widespread neurodegeneration and the accumulation of insoluble amyloid plaques and neurofibrillary tangles. However, at the earliest stages of the disease cell death and pathological tau are localized to the entorhinal cortex. In particular, the lateral entorhinal cortex, and its functions in object-related memory, are among the most vulnerable in aging. Notably, the entorhinal cortex projects directly to the dentate gyrus subregion of the hippocampus, where neurogenesis proceeds throughout adult life. Immature, adult-born neurons provide a robust source of plasticity to the entorhinal-dentate pathway and they may be uniquely responsive, or vulnerable, to early entorhinal tau pathology. To test this, we injected a human tau-expressing recombinant adeno-associated virus into the lateral entorhinal cortex and used AsclCreER mice to birthdate downstream dentate neurons born in early postnatal development or adulthood. Consistent with known roles in neurodegeneration, lateral entorhinal tau expression caused a loss of mushroom spines in downstream dentate neurons and reduced dendritic complexity of adult-born neurons in male mice. Presynaptic tau also increased neurogenesis levels and increased the density of thin spines on adult-born neurons. Despite these morphological effects, tau did not alter synaptic strength or the magnitude of long-term potentiation at entorhinal synapses onto adult- or developmentally-born neurons. Thus, in a novel model of early sporadic tau pathology, there are morphological changes consistent with neurodegeneration but also compensatory neuroplastic changes, caused by neurogenesis. Since immature neurons have also been identified in the human dentate gyrus, a similar neurogenic plasticity may help maintain entorhinal-hippocampal formation in pathological aging. (Comment on this)
6:32p	Neuroanatomy of catecholaminergic circuits in the brainstem and hypothalamus using T1-weighted and diffusion magnetic resonance imaging in humans: implications for brain-immune interactions, cardiovascular disease, neuropsychiatric disorders, stress res Neuroimaging allows the study of brain structures that previously were undetectable due to their small size and location. Here-in we focused on the core catecholaminergic circuitries in the human brain, involving the coerulean noradrenergic (or norepi-nephrine, NE) and dopaminergic (DA) systems. Using T1-weighted MRI morphometry and dMRI tractography, this study was carried out in one post-mortem human ultra-high-resolution dataset of the brainstem and diencephalon and in healthy human datasets from the Human Connectome Project repository. We investigated 26 connections of brainstem origin (13 in the left side and 13 in the right side) associated with the NE and DA circuitries. We delineated the coerulean NE and DA core central cate-cholaminergic circuitries of the brainstem and hypothalamus in the post-mortem dataset, including all targeted fiber connec-tions. Importantly, this was also achieved in the HCP datasets. These results emphasize the importance of multispectral neu-roimaging in the study of chemical neuroanatomical circuitries and its application in clinical conditions such as cardiovascular disease, major depression, schizophrenia, and other disorders associated with chronic stress and brain-immune interactions such as COVID-19. (Comment on this)
6:32p	Neuronal networks in the dorsal hippocampus causally regulate rescue behavior in mice Prosocial behaviors, such as rescuing individuals in need, are crucial for social cohesion across species. While key brain regions involved in rescue behavior have been identified, the underlying neural mechanisms remain unclear. The hippocampus (HPC), known for its role in memory and spatial navigation, also contributes to emotional and social processing. However, its specific involvement in prosocial behavior is not well understood. Here, we investigate the causal role of the HPC in learning and executing rescue behavior in mice. Using chemogenetics, we show that the dorsal HPC (dHPC), but not the ventral HPC (vHPC), is essential for acquiring rescue behavior. Calcium imaging of the dHPC reveals network consolidation during successful rescues, with distinct synchronized ensembles and activity patterns linked to liberations of an individual in need. These findings establish a novel role for the dHPC in prosocial behavior, providing insights into the neural mechanisms underlying empathy-driven actions. (Comment on this)
6:32p	BRAPH 2: a flexible, open-source, reproducible, community-oriented, easy-to-use framework for network analyses in neurosciences As network analyses in neuroscience continue to grow in both complexity and size, flexible methods are urgently needed to provide unbiased, reproducible insights into brain function. BRAPH 2 is a versatile, open-source framework that meets this challenge by offering streamlined workflows for advanced statistical models and deep learning in a community-oriented environment. Through its Genesis compiler, users can build specialized distributions with custom pipelines, ensuring flexibility and scalability across diverse research domains. These powerful capabilities will ensure reproducibility and accelerate discoveries in neuroscience. (Comment on this)
9:20p	Functional connectivity reveals increased network segregation and sensorimotor processing during working memory in adolescents with Neurofibromatosis Type 1 Neurofibromatosis type 1 (NF1) is a rare genetic condition characterised by skin pigmentations, bone deformities, and tumours. Its cognitive phenotype shares similarities with autism spectrum disorder and attention deficit/hyperactivity disorder, including impairments in executive function and working memory processing. In this work, we conducted functional connectivity and graph theory analysis of fMRI data from a sample of neurotypical adolescents (N = 26) and a sample of adolescent NF1 - participants (N = 43). Whole brain comparisons demonstrated that during working memory conditions NF1 participants have greater connectivity in left posterior parietal regions, particularly converging at the postcentral gyrus. Comparison of communication between functional networks demonstrated that NF1 participants have increased connectivity between visual, sensorimotor, dorsal attention and limbic networks. Individual connections were weaker in NF1 participants across the brain, and we found reduced connectivity between control, dorsal attention and default networks in NF1. Furthermore, connectivity strength in these networks was predictive of accuracy and response time in NF1 participants during the task performance. Finally, graph theory analysis showed that working memory demands evoked reorganisation towards greater assortativity in NF1 participants, which was predictive of poorer accuracy and accuracy-speed trade-off. These findings highlight that NF1 participants' working memory deficits emerge from reduced engagement of executive processes, and NF1 participants demonstrate coping mechanisms such as enhanced sensorimotor processing and network reorganisation towards greater segregation, that is however detrimental to cognitive performance. (Comment on this)
9:20p	Fronto-parietal effective connectivity during working memory in Neurofibromatosis Type 1 adolescents and neurotypical controls Background Neurofibromatosis Type 1 (NF1) is a rare, a single-gene neurodevelopmental disorder. Atypical brain activation patterns have been linked to working memory difficulties in NF1 patients. The present work investigated if greater inhibitory activity underlies in interactions between neuronal populations in NF1 patients, as estimated with effective connectivity during working memory ask. Methods Forty-three adolescent patients with NF1 and twenty-six age-matched neurotypical controls completed functional magnetic resonance imaging scans during a verbal working memory task. Dynamic causal models were estimated for bilateral fronto-parietal network (dorsolateral and ventrolateral prefrontal cortices (dlPFC and vlPFC), superior and inferior parietal gyri (SPG and IPG)). Parametric empirical Bayes approach with Bayesian model reduction was used to test the hypothesis that NF1 diagnosis would be characterised by greater inhibitory self-connections (intrinsic connectivity). Leave-one-out cross-validation (LOO-CV) was performed to test the generalisability of group differences. Results NF1 participants have greater average connectivity of left dlPFC, IPG, SPG and bilateral vlPFC. The winning model of Bayesian model reduction investigating effects of working memory showed that NF1 patients have stronger intrinsic connectivity of left vlPFC, but weaker connectivity of right vlPFC and left dlPFC. The parameters of these connections were weakly predictive of NF1 diagnosis; correlation coefficient between true and predicted scores was 0.19 (p = 0.055) Conclusions Increased average connectivity of left dlPFC, IPG, SPG and bilateral vlPFC in NF1, suggests greater overall sensitivity of these regions to inputs. Working memory evoked different patterns of input processing in NF1, that cannot be characterised by increased inhibition alone. Instead, modulatory connectivity related to working memory showed more inhibitory self-connectivity of left dlPFC and left vlPFC, and less inhibitory intrinsic connectivity of right vlPFC in NF1. Importantly, this discrepancy between average and modulatory connectivity suggests that overall NF1 participants are responsive to cognitive task-related inputs but may show atypical adaptation to the task demands of working memory. (Comment on this)
9:20p	Dopaminergic drugs modulate fear extinction related processes in humans, but effects are mild The ability to extinguish learned fear responses is crucial for adaptive behavior. The mesolimbic dopaminergic system originating in the ventral tegmental area has been proposed to contribute to fear extinction learning because of its critical role in reward learning. The unexpected omission of aversive unconditioned stimuli (US) is considered as rewarding (outcome better than expected) and to drive extinction learning. We tested the hypothesis that extinction learning is facilitated by dopaminergic drugs and impeded by anti-dopaminergic drugs. The effects of dopamine agonists [levodopa (100 mg) and bromocriptine (1.25 mg)] and antagonists [tiapride (100 mg) and haloperidol (3 mg)] on fear extinction learning were compared to placebo in 146 young and healthy human participants. A three-day differential fear conditioning paradigm was performed with pupil size and skin conductance responses (SCRs) being recorded. Fear acquisition training was performed on day 1, extinction training on day 2, and recall was tested on day 3. The conditioned stimuli (CS+, CS-) consisted of two geometric figures. A short electrical stimulation was used as the aversive US. One of the four drugs or placebo was administered prior to the extinction phase on day 2. Overall, effects were small and seen only in the bromocriptine group. In line with our hypothesis, we measured reduced pupil dilation during late recall in the bromocriptine group compared to the placebo group, indicating faster re-extinction of spontaneously recovered fear reactions on the third day. Effects of levodopa and haloperidol were unspecific and related to generally increased SCR levels in the levodopa group (already prior to drug intake), and miotic side-effects of haloperidol. Findings provide additional support that the dopaminergic system contributes to extinction learning in humans, possibly by improving consolidation of fear extinction memory. (Comment on this)
9:20p	PsiConnect: A Multimodal Neuroimaging Study of Psilocybin-Induced Changes in Brain and Behaviour PsiConnect is a large-scale neuroimaging study designed to investigate the neural and subjective effects of psilocybin using multimodal neuroimaging. It combines functional, structural, and diffusion-weighted MRI with EEG to examine brain activity in 62 participants before and after a 19 mg dose of psilocybin. The design includes resting-state scans and three naturalistic conditions: guided meditation, music listening, and movie watching. Half of the cohort underwent an 8-week meditation training program, enabling the exploration of interactions among meditation, psilocybin, and brain function. The fMRI data was obtained through multi-echo fMRI, which enhances the signal-to-noise ratio and reduces susceptibility artifacts, thereby improving the reliability of the analyses. A comprehensive battery of behavioural and self-report measures captured both acute and longitudinal cognitive and subjective effects, with follow-ups extending to one year post-administration. The large sample size, multimodal neuroimaging, diversity of contexts, and longitudinal behavioural follow-ups enable the study of psilocybin-induced changes in brain and behaviour with an unprecedented level of detail and reliability. Furthermore, the data is curated according to open science principles to ensure accessibility and interoperability with established neuroimaging processing pipelines. These factors make PsiConnect a valuable and highly reusable resource for researchers in cognitive and computational neuroscience. (Comment on this)

<< Previous Day

2025/04/14 [Calendar]

Next Day >>