An Overview of the Brainstem

Haines, Duane E.; Mihailoff, G.A.

doi:10.1016/b978-0-323-39632-5.00010-4

Cited by 5 publications

(1 citation statement)

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“…Linninger et al [36] Third ventricle volume 3.60ml 2.48ml Linninger et al [36] Fourth ventricle volume 2.69ml 3.31ml Linninger et al [36] Subarachnoid space volume 292.08ml 179 ml (only cranial) Chazen et al [15] Aqueduct diameter 2.88 mm 1.5 to 3.0 mm Haines and Mihailoff [28] Spinal canal (C3) diameter 12 mm 9.4 to 17.2 mm Ulbrich et al [57] Spinal coord (C3) diameter 7 mm 6.0 to 9.6 mm Ulbrich et al [57] Brain parenchyma total volume 1369.54ml 1130 ml (women) 1260 ml (men)…”

Section: Literature Value Referencesmentioning

confidence: 99%

Human intracranial pulsatility during the cardiac cycle: a computational modelling framework

Causemann

Vinje

Rognes

2022

Preprint

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Background: Today's availability of medical imaging and computational resources set the scene for high-fidelity computational modelling of brain biomechanics. The brain and its environment feature a dynamic and complex interplay between the tissue, blood, cerebrospinal fluid (CSF) and interstitial fluid (ISF). Here, we design a computational platform for modelling and simulation of intracranial dynamics, and assess the models' validity in terms of clinically relevant indicators of brain pulsatility. Methods: We develop finite element models of fully coupled cardiac-induced pulsatile CSF flow and tissue motion in the human brain environment. The three-dimensional model geometry is derived from magnetic resonance images (MRI), features a high level of detail including the brain tissue, the ventricular system, and the cranial subarachnoid space (SAS). We model the brain parenchyma at the organ-scale as an elastic medium permeated by an extracellular fluid network and describe flow of CSF in the SAS and ventricles as viscous fluid movement. Representing vascular expansion during the cardiac cycle, a pulsatile net blood flow distributed over the brain parenchyma acts as the driver of motion. Additionally, we investigate the effect of model variations on a set of clinically relevant quantities of interest. Results: Our model predicts a complex interplay between the CSF-filled spaces and poroelastic parenchyma in terms of ICP, CSF flow, and parenchymal displacements. Variations in the ICP are dominated by their temporal amplitude, but with small spatial variations in both the CSF-filled spaces and the parenchyma. Induced by ICP differences, we find substantial ventricular and cranial-spinal CSF flow, some flow in the cranial SAS, and small pulsatile ISF velocities in the brain parenchyma. Moreover, the model predicts a funnel-shaped deformation of parenchymal tissue in dorsal direction at the beginning of the cardiac cycle. Conclusions: Our model accurately depicts the complex interplay of ICP, CSF flow and brain tissue movement and is well-aligned with clinical observations. It offers a qualitative and quantitative platform for detailed investigation of coupled intracranial dynamics and interplay, both under physiological and pathophysiological conditions.

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Section: Literature Value Referencesmentioning

confidence: 99%

Human intracranial pulsatility during the cardiac cycle: a computational modelling framework

Causemann

Vinje

Rognes

2022

Preprint

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Deep brain stimulation of the brainstem

Elias

Loh

Gwun

et al. 2020

Brain

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Deep brain stimulation (DBS) of the subthalamic nucleus, pallidum, and thalamus is an established therapy for various movement disorders. Limbic targets have also been increasingly explored for their application to neuropsychiatric and cognitive disorders. The brainstem constitutes another DBS substrate, although the existing literature on the indications for and the effects of brainstem stimulation remains comparatively sparse. The objective of this review was to provide a comprehensive overview of the pertinent anatomy, indications, and reported stimulation-induced acute and long-term effects of existing white and grey matter brainstem DBS targets. We systematically searched the published literature, reviewing clinical trial articles pertaining to DBS brainstem targets. Overall, 164 studies describing brainstem DBS were identified. These studies encompassed 10 discrete structures: periaqueductal/periventricular grey (n = 63), pedunculopontine nucleus (n = 48), ventral tegmental area (n = 22), substantia nigra (n = 9), mesencephalic reticular formation (n = 7), medial forebrain bundle (n = 8), superior cerebellar peduncles (n = 3), red nucleus (n = 3), parabrachial complex (n = 2), and locus coeruleus (n = 1). Indications for brainstem DBS varied widely and included central neuropathic pain, axial symptoms of movement disorders, headache, depression, and vegetative state. The most promising results for brainstem DBS have come from targeting the pedunculopontine nucleus for relief of axial motor deficits, periaqueductal/periventricular grey for the management of central neuropathic pain, and ventral tegmental area for treatment of cluster headaches. Brainstem DBS has also acutely elicited numerous motor, limbic, and autonomic effects. Further work involving larger, controlled trials is necessary to better establish the therapeutic potential of DBS in this complex area.

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Human intracranial pulsatility during the cardiac cycle: a computational modelling framework

Causemann

Vinje

Rognes

2022

Preprint

View full text Add to dashboard Cite

BackgroundToday’s availability of medical imaging and computational resources set the scene for high-fidelity computational modelling of brain biomechanics. The brain and its environment feature a dynamic and complex interplay between the tissue, blood, cerebrospinal fluid (CSF) and interstitial fluid (ISF). Here, we design a computational platform for modelling and simulation of intracranial dynamics, and assess the models’ validity in terms of clinically relevant indicators of brain pulsatility.MethodsWe develop finite element models of fully coupled cardiac-induced pulsatile CSF flow and tissue motion in the human brain environment. The three-dimensional model geometry is derived from magnetic resonance images (MRI), features a high level of detail including the brain tissue, the ventricular system, and the cranial subarachnoid space (SAS). We model the brain parenchyma at the organ-scale as an elastic medium permeated by an extracellular fluid network and describe flow of CSF in the SAS and ventricles as viscous fluid movement. Representing vascular expansion during the cardiac cycle, a pulsatile net blood flow distributed over the brain parenchyma acts as the driver of motion. Additionally, we investigate the effect of model variations on a set of clinically relevant quantities of interest.ResultsOur model predicts a complex interplay between the CSF-filled spaces and poroelastic parenchyma in terms of ICP, CSF flow, and parenchymal displacements. Variations in the ICP are dominated by their temporal amplitude, but with small spatial variations in both the CSF-filled spaces and the parenchyma. Induced by ICP differences, we find substantial ventricular and cranial-spinal CSF flow, some flow in the cranial SAS, and small pulsatile ISF velocities in the brain parenchyma. Moreover, the model predicts a funnel-shaped deformation of parenchymal tissue in dorsal direction at the beginning of the cardiac cycle.ConclusionsOur model accurately depicts the complex interplay of ICP, CSF flow and brain tissue movement and is well-aligned with clinical observations. It offers a qualitative and quantitative platform for detailed investigation of coupled intracranial dynamics and interplay, both under physiological and pathophysiological conditions.

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An Overview of the Brainstem

Cited by 5 publications

References 0 publications

Human intracranial pulsatility during the cardiac cycle: a computational modelling framework

Human intracranial pulsatility during the cardiac cycle: a computational modelling framework

Deep brain stimulation of the brainstem

Human intracranial pulsatility during the cardiac cycle: a computational modelling framework

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