Functional connectivity

…of communication “effective” or “functional” connectivity. In the motor system, within-day learning may rely primarily on modulation of networks, although the source of this modulation is unclear [1]. Over longer timescales, changes in anatomical connectivity can shape behavior through processes like Hebbian plasticity [2]. Understanding how these mechanisms combine to shape learning will require measurements of anatomical and functional c

Understanding the structural and functional network architectures of nervous systems has been a key focus of neuroscience. Many features of brain-wide neuronal networks have been identified in mammals using noninvasive methods that lack cellular information. Here, we performed whole-brain calcium imaging in zebrafish larvae to investigate the structural and genetic basis of functional connectivity (FC) at single-cell resolution. Neural activity from $\sim$50,000 neurons was recorded in head-restrained transgenic larvae expressing a pan-neuronal calcium sensor, while monitoring their tail movem

Functional connectivity has been the focus of many research groups aiming to study the interaction between cells and brain regions. A standard method for analyzing connectivity is to statistically compare pairwise interactions between cells or brain regions across behavioral states or conditions. This methodology ignores the intrinsic properties of functional connectivity as a multivariate and dynamic signal, expressing the correlational configuration of the network. In this talk, I will present a geometric approach, combining Graph Theory and Riemannian Geometry to build "a graph of graphs" a

While anatomical connectivity changes slowly through synaptic learning, the functional connectivity of neurons changes rapidly with ongoing activity of neurons and their functional interactions. Functional networks of neurons and neural populations reflect how their interactions change with behaviors, stimulus types, and internal states. Therefore, the information propagation across a network can be analyzed through the varying topological properties of the functional networks. Our study investigates the functional networks of the visual cortex at both the single-cell and population levels. Ou

…characteristics -spectral power and functional connectivity- across a cohort of 1674 patients with attention-deficit/hyperacti

Neuronal cultures and human stem-cell-derived organoids are fundamental building blocks of neuroscientific research and future personalized medicine. However, in-vitro networks show considerably more synchronous bursting activity than networks in-vivo [1]. One leading theory proposes that under a lack of external input, maladapted network’s plasticity leads to a pathological collective activity pattern: long periods of quiescence are interspersed with bursts of strong, synchronous activity [2, 3]. In theoretical simulations, weak external input can reduce this bursting behavior. However, expe

All-optical techniques play a pivotal role in the direct interrogation of biological neural networks and the investigation of their computational properties. Such techniques combine spatiotemporally precise optogenetic stimulation at cellular resolution to manipulate neuronal states in the network with optical imaging of fluorescent genetically-encoded indicators for simultaneous readout of neuronal activity [1, 2]. The biophysical models of various optogenetic tools have been studied computationally in single neurons, accurately fitting experimental data [3, 4]. However, the effects of optoge

…potentials [1]-[3] and source-level functional connectivity analyses based on amplitude envelope correlation [4]. Seventy-six subjects participated in the two separate driving experiments including reactive (19 young, 28 ol

Brain activity lies on a very complex network. This complexity is multiple but a prominent one is the non-linear and multi-factorial interaction between its nodes. In the specific case of Parkinson's disease (PD), the brain loses dopaminergic neurons in the substantia nigra compacta (SNc). Highly involved in the basal ganglia-cortex-thalamus-cerebellum (BG-Ctx-T-Cb) network, the main role of dopamine (DA) is in learning, decision-making and motor control, as manifested in the PD symptoms such as rigidity, slowness of movements, tremor and poor behavioural flexibility. Following DA loss, the un

Chronic pain is a serious clinical and scientific problem, affecting 1 in 5 people worldwide, yet its mechanisms and ways to treat it remain poorly understood. Pain is modulated by endogenous pain modulatory pathways that connect the brain to the spinal cord, up- and down-regulating the transmission of nociceptive information. The most important region when such modulation occurs is the Rostral Ventromedial Medulla (Fields et al., 1983; Chen and Heinricher, 2022). Despite extensive work characterising the responses of RVM cells during pharmacological interventions, little is currently known ab

Cognitive flexibility plays a key role in ensuring an individual's survival. The prefrontal cortex and striatum are both essential to cognitive flexibility but competing theories debate which structure among these two leads the role in detecting and representing new circumstances for a change, giving largely opposing predictions on neural activities in the prefrontal cortex and striatum during flexible behavior. We trained head-restrained mice to perform an action-outcome based dynamic foraging task and simultaneously recorded single-neuron activities in the medial prefrontal cortex (mPFC)

Associative learning is crucial for adapting to environmental changes. Interactions among neuronal populations involving the dorso-medial prefrontal cortex (dmPFC) in rodents are proposed to regulate associative memory. However, how these neuronal populations store and process information about the association remains unclear. Here we developed a pipeline for longitudinal two-photon imaging and computational dissection of neural population activities in male mouse dmPFC during fear-conditioning procedures, enabling us to detect learning-dependent changes in the dmPFC network topology. After co

Amyloid-beta (Aβ)-induced changes in neuronal activity could yield valuable early markers of Alzheimer’s disease (AD). The neurophysiological manifestations associated with early Aβ-pathology in humans are however not well defined. This study investigated the relationship between Aβ-pathology and neurophysiological characteristics in 110 cognitively unimpaired individuals (65.9±5.7 years). All subjects underwent 18F-flutemetamol-PET imaging and resting-state magnetoencephalography (MEG) recording at baseline and 4-year follow-up. We tested associations between baseline Aβ-binding potentials (B

The Autism Spectrum Disorder (ASD) is a pervasive neurodevelopmental condition, more prevalent in males, characterized by social behavior impairments. Exposure to valproic acid (VPA) during pregnancy is linked to ASD. In our VPA-mouse model experiment, we examined neuronal activation in the social decision-making network (SDMN) and stress-regulatory nuclei in the brain of juvenile male mice across diverse social settings. VPA treatment effectiveness was validated through a three-chamber sociability test, a standard method for measuring ASD-like behavior. WE used c-Fos immunohistochemistry to c

…This functional Magnetic Resonance Imaging (fMRI) study investigated the effect of negative and positive arousal on memory of unrelated, neutral information presented following arousal exposure. Considering a decline in episodic memory retrieval and alterations in emotion regulation processes that occur in healthy ageing, we aimed to examine the effect of arousal on memory in young and old adults. Our findings indicate that both gr

…Here, we describe task-based functional connectivi

…Using functional ultrasound (fUS) imaging, we studied the dynamics of the alterations of brain activation and functional connectivity (FC) patterns, measured through the neurovascular coupling, in a 60 minutes period following cannabinoid treatment in awake and behaving C57/BL6J mice. We then correlated these changes with important behavioral and molecular readouts, specifically locomotion, analgesia and CB1 receptor (CB1R) activation, measured by CB1R phosphorylation.Results

…connections in cortical structural connectivity (SC). These damages manifest as losses in connections or demyelination of axons. When the SC of the brain is damaged, the functional connectivity (FC, i.e. the dynamic interactions and information exchange between distinct brain regions) is locally and globally perturbed. Despite the close correlation between SC and FC, they are not identical; FC exhibits greater flexibility and can reorganize in resp

The complement system is an innate immune pathway that responds to pathogens and cellular stress. The complement receptor C3aR is expressed on various brain cells, especially microglia. C3a, the ligand of C3aR, is elevated in several psychiatric disorders, such as psychosis, schizophrenia, bipolar disorder and depression. Previous studies have shown that mice lacking C3aR exhibit behavioural abnormalities, including anxiety, hyperactivity, and working memory deficit. These findings indicate that C3aR is involved in the development and/or function of brain circuits. We performed a brain imaging

…The functional connectome captures how brain areas communicate and graph theory analyses can characterise this at a network level. We modeled typical developmental trajectories of the functional connectome using graph theory to explore network-level development during childhood and adolescence. Using resting state functional MRI, we measured functional connectivity between 106 ROIs (Harvard-Oxford atlas), in a cross-sectional

…Research suggests that alterations in functional connectivity within and between cortical and subcortical areas optimize interregional communication, impacting reward processing and decision-making. Hormonal changes, notably gonadal hormones, significantly influence adolescent behavior and brain development. This study aims to elucidate adolescent behavior through a reward learning paradigm while investigating underlying neuronal

…Yet, whether and how the functional organization of this network differs remains poorly understood. Using resting-state functional magnetic resonance imagery, we show that the functional connectivity (FC) between AMG nuclei and mPFC regions differs between humans and awake macaques. In humans, the AMG-mPFC FC displays U-shaped pattern along the corpus callosum: a positive FC with the ventromedial p

…Thus, functional connectivity (FC) studies are pivotal for unraveling autism-related large-scale network dynamics. Although functional imaging studies during development can be instrumental for autism diagnosis, longitudinal studies of FC consolidation over development to adulthood are missing in mice. SHANK3 is a postsynaptic scaffolding protein of excitatory synapses. Its deletion or mutation is

This study explores the impact of past experiences on resting state brain networks in animals, particularly focusing on the difference between naive mice and those subjected to contextual fear conditioning. We analyzed the resting activity of 41 brain regions, observing significant changes in brain activity 24 hours post-learning. Mice with associative learning experience showed a notable increase in c-Fos-positive cells in specific brain areas known for their role in fear memory formation, such as the prelimbic, retrosplenial, and temporal associative cortex, alongside various amygdala nuclei