Thalamic contributions to the state and contents of consciousness

Neuron, Journal Year: 2024, Volume and Issue: 112(10), P. 1611 - 1625

Published: May 1, 2024

Consciousness can be conceptualized as varying along at least two dimensions: the global state of consciousness and content conscious experience. Here, we highlight cellular systems-level contributions thalamus to then argue for thalamic content, including integrated, segregated, continuous nature our We underscore vital, yet distinct roles core- matrix-type neurons. Through reciprocal interactions with deep-layer cortical neurons, matrix neurons support wakefulness determine perceptual thresholds, whereas core maintain enable constancy. further propose that integration, segregation, continuity depend on convergent corticothalamic projections enabling dimensionality reduction, a reticular nucleus-mediated divisive normalization-like process, sustained coherent activity in thalamocortical loops, respectively. Overall, conclude plays central topological role brain structures controlling

Language: Английский

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Thalamocortical architectures for flexible cognition and efficient learning

Trends in Cognitive Sciences, Journal Year: 2024, Volume and Issue: 28(8), P. 739 - 756

Published: June 17, 2024

The brain exhibits a remarkable ability to learn and execute context-appropriate behaviors. How it achieves such flexibility, without sacrificing learning efficiency, is an important open question. Neuroscience, psychology, engineering suggest that reusing repurposing computations are part of the answer. Here, we review evidence thalamocortical architectures may have evolved facilitate these objectives flexibility efficiency by coordinating distributed computations. Recent work suggests prefrontal cortical networks compute with flexible codes, mediodorsal thalamus provides regularization promote efficient reuse. Thalamocortical interactions resemble hierarchical Bayesian computations, their network implementation can be related existing gating, synchronization, hub theories thalamic function. By reviewing recent findings providing novel synthesis, highlight key research horizons integrating computation, cognition, systems neuroscience.

Language: Английский

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Rapid context inference in a thalamocortical model using recurrent neural networks

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Sept. 27, 2024

Language: Английский

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Evidence for direct dopaminergic connections between substantia nigra pars compacta and thalamus in young healthy humans

Frontiers in Neural Circuits, Journal Year: 2025, Volume and Issue: 18

Published: Jan. 9, 2025

The substantia nigra pars compacta (SNc), one of the main dopaminergic nuclei brain, exerts a regulatory function on basal ganglia circuitry via nigro-striatal pathway but its possible innervation thalamus has been only investigated in non-human primates. impossibility tract-tracing studies humans boosted advanced MRI techniques and multi-shell high-angular resolution diffusion (MS-HARDI) promised to shed more light structural connectivity subcortical structures. Here, we estimated human an MS-HARDI tractography SNc healthy young adults. Two data sets were serially acquired using schemes from ADNI HCP neuroimaging initiatives group 10 subjects (5 males, age range: 25-30 years). High 3D-T1 images independently individually segment SNc. Starting whole-brain probabilistic tractography, all streamlines through reaching counted, separately for each hemisphere, after excluding reticulata those ganglia, cerebellum cortex. We found reproducible between thalamus, with average ~12% total number encompassing terminating no other major or cortical structures involved. first principal component map dopamine receptor density normative PET image set suggested similar levels across thalamus. This is quantitative report in-vivo measurements supporting presence direct nigro-thalamic projection. While histological validation concurrent PET-MRI remains needed ultimate proofing existence, given potential role this pathway, possibility achieve good reproducibility these might enable monitoring dopaminergic-related disorders, towards targeted personalized therapies.

Language: Английский

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Mediodorsal thalamus regulates task uncertainty to enable cognitive flexibility

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: March 18, 2025

The mediodorsal (MD) thalamus is a critical partner for the prefrontal cortex (PFC) in cognitive control. Accumulating evidence has shown that MD regulates task uncertainty decision making and enhance flexibility. However, computational mechanism of this process remains unclear. Here we trained biologically-constrained models to delineate mechanistic role context-dependent making. We show addition feedforward structure recurrent PFC increases robustness low cueing signal-to-noise ratio, enhances working memory, enables rapid context switching. Incorporating genetically identified thalamocortical connectivity interneuron cell types into model replicates key neurophysiological findings task-performing animals. Our reveals mechanisms geometric interpretations regulating cue switching enable makes experimentally testable predictions linking deficits with disrupted connectivity, excitation-inhibition imbalance dysfunctional inhibitory types. by which activity flexibility not fully understood. authors build incorporating Together experimental testing, circuit

Language: Английский

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Anatomical characterisation of somatostatin-expressing neurons belonging to the anterolateral system

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: March 20, 2025

Abstract Anterolateral system (ALS) spinal projection neurons are essential for pain perception. However, these cells heterogeneous, and there has been extensive debate about the roles of ALS populations in different dimensions. We recently performed single-nucleus RNA sequencing on a developmentally-defined subset neurons, identified 5 transcriptomic populations. One these, ALS4, consists that express Sst , gene coding somatostatin, we reported were located lateral part lamina V. Here use Cre mouse line to characterise define their axonal projections. find axons ascend mainly ipsilateral side, giving off collaterals throughout course cord. They target various brainstem nuclei, including parabrachial internal nucleus, posterior triangular medial dorsal thalamic nuclei. also show L4 segment is expressed by ~ 75% V around 120 -positive each side. Our findings indicate this relatively large population, based targets conclude they likely contribute affective-motivational dimension pain.

Language: Английский

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Whole-brain effective connectivity of the sensorimotor system using 7T fMRI with electrical microstimulation in non-human primates

Progress in Neurobiology, Journal Year: 2025, Volume and Issue: unknown, P. 102760 - 102760

Published: April 1, 2025

The sensorimotor system is a crucial interface between the brain and environment, it endowed with multiple computational mechanisms that enable efficient behaviors. For example, predictive processing via an efference copy of motor command has been proposed as one key computations used to compensate for sensory consequence movement. However, neural pathways underlying this process remain unclear, particularly regarding whether M1-to-S1 pathway plays dominant role in how its influence compares other pathways. In study, we present causally inferable input-output map effective connectivity made by combining ultrahigh-field functional MRI, electrical microstimulation S1/M1 cortex, dynamic causal modeling whole network anesthetized primates. We investigated signals from M1 are transmitted S1 at circuit level, either direct cortico-cortical projections or indirectly subcortical structures such thalamus. Across different stimulation conditions, observed robust asymmetric was also most prominent output M1. thalamus, identified distinct activations: showed connections anterior part ventral thalamic nuclei, whereas linked more posterior regions nuclei. These findings suggest projection S1, rather than cortico-thalamic loop, transmitting movement-related information. Together, our detailed dissection circuitry underscores importance coordination.

Language: Английский

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Modafinil alters the functional connectivity of distinct thalamic nuclei with the neocortex

NeuroImage, Journal Year: 2025, Volume and Issue: unknown, P. 121242 - 121242

Published: April 1, 2025

Modafinil promotes wakefulness and enhances cognitive function through mechanisms neural effects that are still partially unknown. Several studies have shown the compound alters functional cortical architecture. In contrast, its influence on subcortical regions thalamocortical connections, which crucial for modulating neocortical connectivity, remains unexplored. The acute modulation of thalamo-cortical connectivity was assessed in two groups participants who received either a single 100 mg dose modafinil (N=25) or placebo (N=25). Magnetic Resonance Imaging (MRI) used to parcel thalamus into constituent nuclei, served as seeds voxel-wise resting state analyses. Additionally, maps nuclei-specific reorganization were compared those receptor/transporter expression assess their spatial overlaps. Modafinil, but not placebo, altered three thalamic nuclei. Specifically, medial pulvinar nuclei showed increased with Sensorimotor Salience/Ventral Attention (SVAN) Networks. These changes spatially overlapped distribution norepinephrine transporter (NET). anterior inferior complex exhibited enhanced insular supramarginal SVAN superior frontal area Default Mode Network (DMN). However, unlike pulvinar, these linked any specific receptor transporter. Finally, ventrolateral posterior region DMN FrontoParietal Network, along decreased premotor cortex. topography modifications mainly overlaps glutamatergic serotonergic receptors. summary, our findings highlight modafinil's circuits, emphasizing role higher-order complex.

Language: Английский

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Developing algorithmic psychiatry via multi-level spanning computational models

Cell Reports Medicine, Journal Year: 2025, Volume and Issue: unknown, P. 102094 - 102094

Published: April 1, 2025

Language: Английский

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In relentless pursuit of the white whale: A role for the ventral midline thalamus in behavioral flexibility and adaption?

Neuroscience & Biobehavioral Reviews, Journal Year: 2024, Volume and Issue: 163, P. 105762 - 105762

Published: June 12, 2024

The reuniens (Re) nucleus is located in the ventral midline thalamus. It has fostered increasing interest, not only for its participation a variety of cognitive functions (e.g., spatial working memory, systemic consolidation, reconsolidation, extinction fear or generalization), but also neuroanatomical positioning as bidirectional relay between prefrontal cortex (PFC) and hippocampus (HIP). In this review we compile discuss recent studies having tackled possible implication Re behavioral flexibility, major PFC-dependent executive function controlling goal-directed behaviors. Experiments considered explored role perseveration, reversal learning, extinction, set-shifting. They point to contribution mainly by connections with PFC, possibly those hippocampus, even amygdala, at least fear-related behavior. As such, could be crucial crossroad supporting PFC-orchestrated ability cope new, potentially unpredictable environmental contingencies, thus flexibility adaption.

Language: Английский

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