Background And Purpose: In 1948, Paul Yakovlev described an additional limbic circuit located basolateral to James Papez's circuit (1937) and included orbitofrontal cortex, amygdala, and dorsomedial nucleus of thalamus. This circuit is shown to be an important component of subcortical cognitive abilities. We aimed to demonstrate this circuit in a multiple sclerosis (MS) cohort using diffusion tensor imaging (DTI) and evaluate its role in MS-related cognitive impairment (CI).
Methods: We enrolled cognitively intact (n = 10) and impaired (n = 36) MS patients who underwent a comprehensive cognitive assessment; the minimal assessment of cognitive function in MS (MACFIMS) and structural magnetic resonance imaging. Correlation analyses between volumetric and DTI-derived values of the orbitofrontothalamic (OFT), amygdalothalamic tracts (ATTs), and dorsomedial nucleus of thalamus and CI index derived from MACFIMS were computed after adjustment for age, education, and lesion load.
Results: We observed a consistent trend between CI index and bilateral dorsomedial nucleus' mean diffusivity (MD) (r = .316; P = .02), left OFT Fractional anisotropy (FA) (r = -.302; P = .02), MD (r = .380; .006), and radial diffusivities (RDs) (r = .432; P = .002), also with right ATT FA (r = -.475; P = .0006) and left ATT FA ( = -.487; P = .0005). After Bonferroni correction, correlations of left OFT RD and right and left ATT FA with CI were found to be significant.
Conclusions: Our study provides in vivo DTI delineation of Yakovlev's historical basolateral limbic circuit and establishes a role in MS-related CI. These findings may potentially pave the way for future clinical studies using targeted invasive and noninvasive neurostimulation modalities for CI in MS.
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http://dx.doi.org/10.1111/jon.12531 | DOI Listing |
Elife
January 2025
Centre for Neuroscience, Indian Institute of Science, Bengaluru, India.
Stress is a potent modulator of pain. Specifically, acute stress due to physical restraint induces stress-induced analgesia (SIA). However, where and how acute stress and pain pathways interface in the brain are poorly understood.
View Article and Find Full Text PDFPharmacol Res
January 2025
Post-surgical pain affects millions each year, hindering recovery and quality of life. Surgical procedures cause tissue damage and inflammation, leading to peripheral and central sensitization, resulting in pain at rest or hyperalgesia to mechanical stimuli, among others. In a rat model for post-surgical pain, spinal GABAergic transmission via GABA receptors reduces mechanical hypersensitivity but has no effect on pain at rest.
View Article and Find Full Text PDFCommun Med (Lond)
January 2025
Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Background: Alzheimer's disease (AD) is a serious neurodegenerative disorder without a clear understanding of pathophysiology. Recent experimental data have suggested neuronal excitation-inhibition (E-I) imbalance as an essential element of AD pathology, but E-I imbalance has not been systematically mapped out for either local or large-scale neuronal circuits in AD, precluding precise targeting of E-I imbalance in AD treatment.
Method: In this work, we apply a Multiscale Neural Model Inversion (MNMI) framework to the resting-state functional MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) to identify brain regions with disrupted E-I balance in a large network during AD progression.
Debilitating anxiety is pervasive in the modern world. Choices to approach or avoid are common in everyday life and excessive avoidance is a cardinal feature of all anxiety disorders. Here, we used intracranial EEG to define a distributed prefrontal-limbic circuit dynamics supporting approach and avoidance.
View Article and Find Full Text PDFJ Neurosci
January 2025
Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI USA
Based on the activity of dopamine (DA) neurons during behavioral states, the DA system has long been thought to be foundational in regulating sleep-wake behavior; over the past decade advances in circuit manipulation and recording techniques have strengthened this perspective. Recently, several studies have demonstrated that DA release in regions of the limbic system is important in the promotion of REM sleep. Yet how DA dynamics change within bouts of sleep, how these changes are regulated, and whether they influence future state changes remains unclear.
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