Default mode network

Vinod Menon examines the brain's default mode network as a foundation for autobiographical memory, self-related processing, and consciousness, and considers how these functions compare with current artificial intelligence systems. The virtual session is part of Stanford's Contemplation by Design Summit.

Synchronization of dispersed brain areas comprising the Default Mode Network (DMN) has been implicated in a range of cognitive processes (e.g., episodic memory retrieval, dream recall, creativity) [1,2]. Here, we probe the role of the DMN in divergent thinking through intracranial recordings in 8 patients with electrodes implanted for epilepsy monitoring. Subjects performed a creativity-requiring alternate uses task (AUT) and two control tasks (Fig. 1a)—a basic arithmetic task (BAT) and an object characterization task (OCT). The originality of subjects’ AUT responses was automatically scored u

…is transdiagnostically associated with default mode network dysconnectivity. Low social functioning groups exhibit decreased DTI fractional anisotropy in backbone structures of the DMN such as forceps minor, the interhemispheric connection of the orbitofrontal cortices (OFC). This study aims to back-translate these data by understanding the role of parvalbumin interneurons (PV+) in OFC.We studied the effect PV+ interneuron activation on social behaviors in mice by using an a

The default mode network`s (DMN) can be investigated using default EEG reactivity (DER).The default oscillatory macrostate (DEM) is exemplified by the macrostate showing thehighest decrease in occurrence probability during intermittent photic stimulation (IPS).This study aimed to investigate DER, in the deeply sedated epileptic brain.We used a genetic rat model of absence epilepsy, the adult Wistar Albino Glaxo Rijwijk(WAG/Rij) rat. Controls consisted of age-matched Wistar rats.Deep aesthetic coma was induced by chloral hydrate. We performed cortical EEG recordingsduring the induced altered st

Anxiety is an emotional state that orients cognition towards potential future threat. Despite serving a useful function, this can be unpleasant and pathological when experienced chronically, or in inappropriate situations. Simple strategies for emotion regulation, such as self-distancing and attention-focusing can reduce perceived negative emotion, but the neural mechanisms are unclear. This study aims to investigate brain responses underlying the efficacy of these interventions, by combining self-reported anxiety measures and fMRI data.Prior to scanning, personalised, anxiety-provoking scenar

…altered connectivity of the brain’s default mode network (DMN) could predict poor outcomes. Unfortunately, functional imaging is not easily applicable at the bedside.We proposed a neurophysiological method that assesses DMN function by computing the default EEG reactivity (DER). The method maps continuous EEG to a sequence of recurring oscillatory patterns termed macrostates. We labelled the default EEG macrostate (DEM) as the macrostate with the lowest probabili

Alzheimer’s disease (AD) is believed to have a prolonged preclinical phase when aggregates of soluble, neurotoxic tau and amyloid species accrue and slowly develop into positron emission tomography (PET)-detectable neurofibrillary tangles and amyloid plaques, respectively, which in turn herald the onset of mild cognitive impairment (MCI) and dementia. Hence, understanding the spatiotemporal timeline for the accrual of these early pathological species prior to PET detection and clinical symptoms will facilitate the development of disease-modifying AD therapies. In this study, we quantified the

…a trio of domain-specific generative models (Fig 1a) within prefrontal (PFC) nodes of the Default-Mode Network (DMN), and integrate within its parietal nodes, forming the basis for our dynamic consciousness.Smoothed binary ratings of prediction updates for State changes, Agent beliefs, and Action sequences from an online sample were used as parametric regressors for the GLMs. These ratings indicating experience shifts

Whole-brain imaging methods such as functional Magnetic Resonance Imaging (fMRI) are widely used to examine intrinsic and task-evoked patterns of coordinated brain activity in humans. However, the application of task-based fMRI in preclinical species is complicated by the need to constrain animals within the scanner small bore. Recently, functional ultrasound imaging (fUS) has emerged as a promising technology to fill this gap, enabling neuroimaging investigations of the entire brain in behaving animals. To explore the potential of fUS, and demonstrate its validity against well-established tec

…connectivity, more specifically on the default mode network, and the impact of the modulation of TrkB receptor on this effect. Methods. Functional Ultrasou

Childhood stroke is a severe but rare disorder with increasing incidence. Early research assumed an improved outcome due to better neuronal plasticity in childhood stroke patients as compared to adults. However, more recent studies indicate similar rates of disabilities and cognitive impairment. Here, we used resting-state fMRI to study transient brain states and their association with cognitive outcome in children and adolescents after childhood stroke. We used clustering analysis to characterize eight recurring spatial co-activation patterns (CAPs) in a cohort of 19 patients and 17 age-match

…connectivity in resting-state networks. An unsupervised machine-learning method, sparse partial least squares analysis (SPLS) captures latent variables from clinical features and brain mechanisms, allowing the examination of relationships between functional connectivity and cognitive functions across disorders. This study aimed to explore relationships between functional connectivity, cognitive domains and study groups using SPLS. 990 participants with recent-onset p

The Default Mode Network (DMN) is a task-negative network composed of mainly cortical areas with elevated activity during ‘autopilot’ states and decreased activity during goal-directed behavior. Work from our laboratory implicates a basal forebrain node, the ventral pallidum (VP), in the regulation of DMN, suggesting that it dramatically impacts transitions between internally and externally guided behaviors. While VP activation has been shown to positively correlate with DMN upregulation and vice versa, it remains unclear which efferent VP neural pathways mediate these effects. We examine this

…connectivity between the salience network and the default mode network (Uddin et al., 2015). Our data indicate that a specific inhibitory neuronal subpopulation plays a fundamental role in salience detection and in gating sensory stimuli to adaptively shape behavior. The aim of the project is to test whether failure in the encoding

Social isolation and loneliness pose major societal challenges whose global spread has been accelerated by the COVID-19 pandemic. Therefore, finding accessible and effective resilience strategies that mitigate the negative affective impact of social isolation on mental health is a top priority.In a cohort study with 317 young adults (mean[SD] age, 23.08 [2.83] years; 181 females [57.09%]), utilizing accelerometry, electronic diaries, and functional neuroimaging, we examined the effectiveness of physical activity in offsetting affective loss due to social isolation in everyday life and investig

…regions collectively known as the default mode network (DMN). While the DMN was initially considered as a cortical network, recent results have provided evidence that some subcortical structures are also involved in DMN regulation. Here we investigated the subcortical nodes, ventral pallidum (VP) and mediodorsal thalamus (MD), in DMN regulation in the tree shrew, a diurnal mammal that is a close relative of primates. We use wireless multichannel recordings and motion tracking,

…of functionally communicating brain networks. Currently, less is known about the similarities and differences of the activation patterns across these functionally related brain regions for each of the distinct WM o

During NREM sleep, the brain is in a self-organized regime in which alternations between spiking and near cessation of spiking propagate along the forebrain, termed slow oscillations (SOs) in the neocortex and SPW-Rs in the hippocampus. Both gain and loss of function studies have demonstrated the importance of tight temporal coordination between SOs and SPW-Rs for systems consolidation, and this temporal coupling has been observed across pairs of regions many synapses removed from one another. However, the spatial extent to which coupling between SPW-Rs and SOs occurs across regions at any one

…emphasize the presence of whole-brain networks organized according to functional and connectivity gradients, but how such structure shapes activity propagation and memory processes still lacks asatisfactory model. We analyse the fine-grained spatiotemporal dynamics of spontaneous activity in the entire dorsal cortex. through simultaneous recordings of wide-field voltage sensitive dye transients (VS), cortical ECoG, and hippocampal LFP in anesthetized mice. Both VS and ECoG show cortical avalanches. When measuring avalanches from the VS

People frequently interpret the same information differently, based on their prior beliefs and views. This may occur in everyday settings, as when two friends are watching the same movie, but also in more consequential circumstances, such as when people interpret the same news differently based on their political views. The role of subjective knowledge in altering how the brain processes narratives has been explored mainly in controlled settings. I will present two projects that examines neural mechanisms underlying narrative interpretation “in the wild” -- how responses differ between two gro