No evidence for three functionally specialized subregions in the subthalamic nucleus: A model-based 7 T fMRI study

The subthalamic nucleus (STN) is a small, subcortical brain structure. It is a target for deep brain stimulation, an invasive treatment that reduces motor symptoms of Parkinson's disease. Side effects of DBS are commonly explained using the tripartite model of STN organization, which proposes three functionally distinct subregions in the STN specialized in cognitive, limbic, and motor processing. However, evidence for the tripartite model exclusively comes from anatomical studies and functional studies using clinical patients. Here, we provide the first experimental tests of the tripartite model in healthy volunteers using ultra-high field 7 Tesla (T) functional magnetic resonance imaging (fMRI). 34 participants performed a random-dot motion decision-making task with a difficulty manipulation and a choice payoff manipulation aimed to differentially affect cognitive and limbic networks. Moreover, participants responded with their left and right index finger, differentially affecting motor networks. We analysed BOLD signal in three subregions of equal volume of the STN along the dorsolateral-ventromedial axis, identified using manually delineated high resolution anatomical images. Our results indicate that all segments responded equally to the experimental manipulations, and did not support the tripartite model.

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Medullary vein architecture modulates the white matter BOLD cerebrovascular reactivity signal response to CO2: observations from high-resolution T2* weighted imaging at 7T

10.1101/2021.09.03.458842 ◽

2021 ◽

Author(s):

Alex A. Bhogal

Keyword(s):

White Matter ◽

High Resolution ◽

Vascular Reactivity ◽

Blood Oxygenation ◽

Cerebrovascular Reactivity ◽

7 Tesla ◽

Hemodynamic Parameters ◽

Vascular Control ◽

Bold Imaging ◽

Anatomical Images

ABSTRACTBrain stress testing using blood oxygenation level-dependent (BOLD) MRI to evaluate changes in cerebrovascular reactivity (CVR) is of growing interest for evaluating white matter integrity. However, even under healthy conditions, the white matter BOLD-CVR response differs notably from that observed in the gray matter. In addition to actual arterial vascular control, the venous draining topology may influence the WM-CVR response leading to signal delays and dispersions. These types of alterations in hemodynamic parameters are sometimes linked with pathology, but may also arise from differences in normal venous architecture. In this work, high-resolution T2*weighted anatomical images combined with BOLD imaging during a hypercapnic breathing protocol were acquired using a 7 tesla MRI system. Hemodynamic parameters including base CVR, hemodynamic lag, lag-corrected CVR, response onset and signal dispersion, and finally ΔCVR (corrected CVR minus base CVR) were calculated in 8 subjects. Parameter maps were spatially normalized and correlated against an MNI-registered white matter medullary vein atlas. Moderate correlations (Pearson’s rho) were observed between medullary vessel frequency (MVF) and ΔCVR (0.52; 0.58 for total WM), MVF and hemodynamic lag (0.42; 0.54 for total WM), MVF and signal dispersion (0.44; 0.53 for total WM), and finally MVF and signal onset (0.43; 0.52 for total WM). Results indicate that, when assessed in the context of the WM venous architecture, changes in the response shape may only be partially reflective of the actual vascular reactivity response occurring further upstream by control vessels. This finding may have implications when attributing diseases mechanisms and/or progression to presumed impaired WM BOLD-CVR.

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Striking parallel between Tonotopy in Auditory Cortex and Retinotopy in Visual Cortex: A human fMRI study at 7 Tesla

Journal of Vision ◽

10.1167/11.11.778 ◽

2011 ◽

Vol 11 (11) ◽

pp. 778-778 ◽

Cited By ~ 1

Author(s):

M. Saenz ◽

W. Van Der Zwaag ◽

J. P. Marques ◽

R. S. Frackowiak ◽

S. Clarke ◽

...

Keyword(s):

Visual Cortex ◽

Auditory Cortex ◽

7 Tesla ◽

Fmri Study

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Basal ganglia and cerebellar contributions to vocal emotion processing: a high resolution fMRI study

10.1101/2020.11.26.399790 ◽

2020 ◽

Author(s):

Leonardo Ceravolo ◽

Sascha Frühholz ◽

Jordan Pierce ◽

Didier Grandjean ◽

Julie Péron

Keyword(s):

Basal Ganglia ◽

High Resolution ◽

Globus Pallidus ◽

Subthalamic Nucleus ◽

Effective Connectivity ◽

Emotion Processing ◽

Brain Regions ◽

Fmri Study ◽

Vocal Emotion

AbstractUntil recently, brain networks underlying emotional voice prosody decoding and processing were focused on modulations in primary and secondary auditory, ventral frontal and prefrontal cortices, and the amygdala. Growing interest for a specific role of the basal ganglia and cerebellum was recently brought into the spotlight. In the present study, we aimed at characterizing the role of such subcortical brain regions in vocal emotion processing, at the level of both brain activation and functional and effective connectivity, using high resolution functional magnetic resonance imaging. Variance explained by low-level acoustic parameters (fundamental frequency, voice energy) was also modelled. Wholebrain data revealed expected contributions of the temporal and frontal cortices, basal ganglia and cerebellum to vocal emotion processing, while functional connectivity analyses highlighted correlations between basal ganglia and cerebellum, especially for angry voices. Seed-to-seed and seed-to-voxel effective connectivity revealed direct connections within the basal ganglia ̶ especially between the putamen and external globus pallidus ̶ and between the subthalamic nucleus and the cerebellum. Our results speak in favour of crucial contributions of the basal ganglia, especially the putamen, external globus pallidus and subthalamic nucleus, and several cerebellar lobules and nuclei for an efficient decoding of and response to vocal emotions.

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The motor inhibitory network in patients with asymmetrical Parkinson’s disease: An fMRI study

Brain Imaging and Behavior ◽

10.1007/s11682-021-00587-5 ◽

2022 ◽

Author(s):

Francis R. Loayza ◽

Ignacio Obeso ◽

Rafael González Redondo ◽

Federico Villagra ◽

Elkin Luis ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Subthalamic Nucleus ◽

Inferior Frontal Gyrus ◽

Stop Signal ◽

Stop Signal Task ◽

Healthy Controls ◽

Inhibitory Network ◽

Fmri Study ◽

The Right

AbstractRecent imaging studies with the stop-signal task in healthy individuals indicate that the subthalamic nucleus, the pre-supplementary motor area and the inferior frontal gyrus are key components of the right hemisphere “inhibitory network”. Limited information is available regarding neural substrates of inhibitory processing in patients with asymmetric Parkinson’s disease. The aim of the current fMRI study was to identify the neural changes underlying deficient inhibitory processing on the stop-signal task in patients with predominantly left-sided Parkinson’s disease. Fourteen patients and 23 healthy controls performed a stop-signal task with the left and right hands. Behaviorally, patients showed delayed response inhibition with either hand compared to controls. We found small imaging differences for the right hand, however for the more affected left hand when behavior was successfully inhibited we found reduced activation of the inferior frontal gyrus bilaterally and the insula. Using the stop-signal delay as regressor, contralateral underactivation in the right dorsolateral prefrontal cortex, inferior frontal and anterior putamen were found in patients. This finding indicates dysfunction of the right inhibitory network in left-sided Parkinson’s disease. Functional connectivity analysis of the left subthalamic nucleus showed a significant increase of connectivity with bilateral insula. In contrast, the right subthalamic nucleus showed increased connectivity with visuomotor and sensorimotor regions of the cerebellum. We conclude that altered inhibitory control in left-sided Parkinson’s disease is associated with reduced activation in regions dedicated to inhibition in healthy controls, which requires engagement of additional regions, not observed in controls, to successfully stop ongoing actions.

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