Rheological properties of the tissues of the central nervous system: A review

Cheng, Shaokoon; Clarke, Elizabeth C.; Bilston, Lynne E.

doi:10.1016/j.medengphy.2008.06.003

Cited by 182 publications

(148 citation statements)

References 41 publications

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“…Our results show decreased elastic rebound from 1 to 3 days following contusion. Given that the elastic behavior of brain tissue is largely a function of the cell structure, 6,26 this change corresponds well to the timing of proteolytic tissue destruction following contusion, which begins at 24 hours. 20 We also observed increased gradual deformation of intracranial contents in the hold-force and multicycle tests.…”

Section: Fig 3 Uppermentioning

confidence: 94%

Intracranial biomechanics following cortical contusion in live rats

Alfasi¹,

Shulyakov

Bigio

2013

JNS

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Object. The goal of this study was to examine the mechanical properties of living rat intracranial contents and corresponding brain structural alterations following parietal cerebral cortex contusion.Methods. After being anesthetized, young adult rats were subjected to parietal craniotomy followed by cortical contusion using a calibrated weight-drop method. Magnetic resonance imaging was used to visualize the contusion. At the site of contusion, instrumented force-controlled indentation was performed 2 hours to 21 days later on the intact dural surface. The force-deformation (stress-strain) relationship was used to calculate elastic (indentation modulus) and strain changes over time, and constant hold or cyclic stress was used to evaluate viscoelastic deformation. These measurements were followed by histological studies.Results. At contusion sites, the indentation modulus was significantly decreased at 1-3 days and tended to be above control values at 21 days. Multicycle indentation showed that the brain tended to accumulate more strain (an indicator of viscosity) by 1 day after the contusion. Imaging and histological studies showed local edema and hemorrhage at 6 hours to 3 days and accumulation of reactive astrocytes, which began at 3 days and was pronounced by 21 days.Conclusions. The viscoelastic properties of living rat brain change following contusion. Initially, edema and tissue necrosis occur, and the brain becomes less elastic and less viscous. Later, along with undergoing reactive astroglial changes, the brain tends to become stiffer than normal. These quantitative data, which are related to the physical changes in the brain following trauma and which reflect subjective impressions upon palpation, will be useful for understanding emerging diagnostic tools such as magnetic resonance elastography.

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Section: Fig 3 Uppermentioning

confidence: 94%

Intracranial biomechanics following cortical contusion in live rats

Alfasi¹,

Shulyakov

Bigio

2013

JNS

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“…Interestingly, the irregularity of the fluid percussion waveform appears to be enhanced in the adolescent rat's cranium (Fig. 4) that is generally agreed to be softer and more compliant than the adult (Cheng et al, 2008;Elkin et al, 2010;Elkin and Morrison, 2013;Shulyakov et al, 2011). While not all studies agree brain stiffens with age (Levchakov et al, 2006), the difference in testing methods could lead to large discrepancies in results.…”

Section: Fluid Percussion Via Motion Controlmentioning

confidence: 96%

“…Tissues of the brain have viscoelastic behavior (Shuck and Advani, 1972;Cheng et al, 2008;Elkin and Morrison, 2013;Shulyakov et al, 2011;Pamidi and Advani, 1978;Wang and Wineman, 1972). At high rates of loading (peak pressure) viscoelastic materials behave stiffer and the magnitude of injury loading will induce higher stresses in the brain with lower amounts of deformation.…”

Section: Fluid Percussion Via Motion Controlmentioning

confidence: 99%

Fluid percussion injury device for the precise control of injury parameters

Wahab

Neuberger

Lyeth

et al. 2015

Journal of Neuroscience Methods

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h i g h l i g h t s• A novel fluid percussion injury (FPI) system was designed and built.• The system generated fluid percussions with independently adjustable peak pressures, rise times and impulses.• Immediate post-injury behavior was similar between the custom FPI system and the commonly used FPI system.• Fluoro-Jade labeling in the hilus and CA2-3 and granule cell population spike amplitude were consistent between systems.• Slow fluid percussion rise times increased mortality and reduced motor function in a subset of adult rats. a r t i c l e i n f o t r a c tBackground: Injury to the brain can occur from a variety of physical insults and the degree of disability can greatly vary from person to person. It is likely that injury outcome is related to the biomechanical parameters of the traumatic event such as magnitude, direction and speed of the forces acting on the head. New method: To model variations in the biomechanical injury parameters, a voice coil driven fluid percussion injury (FPI) system was designed and built to generate fluid percussion waveforms with adjustable rise times, peak pressures, and durations. Using this system, pathophysiological outcomes in the rat were investigated and compared to animals injured with the same biomechanical parameters using the pendulum based FPI system. Results in comparison with existing methods: Immediate post-injury behavior shows similar rates of seizures and mortality in adolescent rats and similar righting times, toe pinch responses and mortality rates in adult rats. Interestingly, post injury mortality in adult rats was sensitive to changes in injury rate. Fluoro-Jade labeling of degenerating neurons in the hilus and CA2-3 hippocampus were consistent between injuries produced with the voice coil and pendulum operated systems. Granule cell population spike amplitude to afferent activation, a measure of dentate network excitability, also showed consistent enhancement 1 week after injury using either system. Conclusions: Overall our results suggest that this new FPI device produces injury outcomes consistent with the commonly used pendulum FPI system and has the added capability to investigate pathophysiology associated with varying rates and durations of injury.

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“…The spinal cord is highly viscoelastic (elastic modulus of 0.5-1 MPa) and experiences up to ~10% of repeated strain during motion [25,26] , presenting a challenge to combined intraspinal neural recording and optical stimulation, since the majority of neural probes and light-delivery devices are comprised of brittle materials [27][28][29] that may cause damage to the neural tissue and fail under repeated deformation [30] . To overcome these limitations, we engineered highly flexible biomimetic all-polymer fiber probes that combine an optical core for optogenetic stimulation and conductive electrodes for simultaneous neural recording.…”

Section: Introductionmentioning

confidence: 99%

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

Froriep

Koppes

et al. 2014

Adv Funct Materials

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Restoration of motor and sensory functions in paralyzed patients requires the development of tools for simultaneous recording and stimulation of neural activity in the spinal cord. In addition to its complex neurophysiology, the spinal cord presents technical challenges stemming from its flexible fibrous structure and repeated elastic deformation during normal motion. To address these engineering constraints, we developed highly flexible fiber probes, consisting entirely of polymers, for combined optical stimulation and recording of neural activity. The fabricated fiber probes exhibit low-loss light transmission even under repeated extreme bending deformations.Using our fiber probes, we demonstrate simultaneous recording and optogenetic stimulation of neural activity in the spinal cord of transgenic mice expressing the light sensitive protein channelrhodopsin 2 (ChR2). Furthermore, optical stimulation of the spinal cord with the polymer fiber probes induces on-demand limb movements that correlate with electromyographical (EMG) activity.

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Rheological properties of the tissues of the central nervous system: A review

Cited by 182 publications

References 41 publications

Intracranial biomechanics following cortical contusion in live rats

Intracranial biomechanics following cortical contusion in live rats

Fluid percussion injury device for the precise control of injury parameters

Polymer Fiber Probes Enable Optical Control of Spinal Cord and Muscle Function In Vivo

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