winter 20 - me234 - intro to neuromechanics

me 234 - intro to neuromechanics 18 me234 youtube channel ellen kuhl summary, announcement, syllabus winter 2020 mon wed fri 2:30-3:20 200-305

me234 youtube channel

dissecting brains

objectives

our brain is not only our softest, but also our least well-understood organ. floating in the cerebrospinal fluid, embedded in the skull, it is almost perfectly isolated from its mechanical environment. not surprisingly, most brain research focuses on the electrical rather than the mechanical characteristics of brain tissue. recent studies suggest though, that the mechanical environment plays an important role in modulating brain function. neuromechanics has traditionally focused on the extremely fast time scales associated with dynamic phenomena on the order of milliseconds. the prototype example is traumatic brain injury where extreme loading rates cause intracranial damage associated with a temporary or permanent loss of function. neurodevelopment, on the contrary, falls into the slow time scales associated with quasi-static phenomena on the order of months. a typical example is cortical folding, where compressive forces between gray and white matter induce surface buckling. to understand the role of mechanics in neuroanatomy and neuromorphology, we begin this course by dissecting mammalian brains and correlate our observations to neurophysiology. we discuss morphological abnormalities including lissencephaly and polymicrogyria and illustrate their morphological similarities with neurological disorders including schizophrenia and autism. then, we address the role of mechanics during brachycephaly, plagiocephaly, tumor growth, and hydrocephalus. last, we explore the mechanics of traumatic brain injury with special applications to shaken baby syndrome.

grading

• 20 % dissection - presentation
  
• 30 % homework - three homework assignments, 10% each
  
• 20 % project presentation - graded by the class
  
• 30 % project report - graded by instructors

previous class projects

harris tc, de rooij r, kuhl e. the shrinking brain: cerebral atrophy following traumatic brain injury. ann biomed eng. 2019; 47:1941-1959. (download)

weickenmeier j, kurt m, ozkaya e, wintermark m, butts pauly k, kuhl e. magnetic resonance elastography of the brain: a comparison between pigs and humans. j mech beh biomed mat. 2018; 77:702-710. (download)

wu lc, ye pp, kuo c, laksari k, camarillo d, kuhl e. pilot findings of brain displacements and deformations during roller coaster rides. j neurotrauma. 2017; 34:3198-3205. (download)

lejeune e, javili a, weickenmeier j, kuhl e, linder c. tri-layer wrinkling as a mechanism for anchoring center initiation in the developing cerebellum. soft matter. 2016;12:5613-5620. (download)

ploch cc, mansi cssa, jayamohan j, kuhl e. using 3D printing to create personalized brain models for neurosurgical training and preoperative planning. world neurosurg. 2016;90:668-674. (download), (perspectives)

syllabus

matlab files

here's the matlab code for brain folding

additional reading

bayly pv, taber la, kroenke cd. mechanical forces in cerebral cortical folding: a review of measurements and models. j mech beh biomed mat. 2014;29:568-581. (download)

budday s, steinmann p, kuhl e. the role of mechanics during brain development. j mech phys solids. 2014:72:75-92. (download)

budday s, nay r, steinmann p, wyrobek t, ovaert tc, kuhl e. mechanical properties of gray and white matter brain tissue by indentation. j mech behavior biomed mat. 2015;46:318-330. (download)

budday s, steinmann p, kuhl e. physical biology of human brain development. front cell neurosci. 2015;9:257. (download)

budday s, sommer g, birkl c, langkammer c, hayback j, kohnert j, bauer m, paulsen f, steinmann p, kuhl e, holzapfel ga. mechanical characterization of human brain tissue. acta biomat. 2017;48:319-340. (download)

dennerll tj, lamoureux p, buxbaum re, heidemann sr. the cytomechanics of axonal elongation and retraction. j cell bio. 1989;109:3073-3083. (download)

franceschini g, bigoni d, regitnig p, holzapfel ga. brain tissue deforms similar to filled elastomers and follows consolidation theory. j mech phys solids. 2006;54:2592-2620. (download)

goriely a, geers mgd, holzapfel ga, jayamohan j, jerusalem a, sivaloganathan s, squier w, van dommelen jaw, waters s, kuhl e. mechanics of the brain: perspectives, challenges, and opportunities. biomech mod mechanobio. 2015;14:931-965. (download)

hardan ay, libove ra, keshavan ms, melhem nm, minshew nj. a preliminary longitudinal magnetic resonance imaging study of brain volume and cortical thickness in autism. biol psych. 2009;66:320-326. (download)

kruse sa, rose gh, glaser kj, manduca a, felmlee jp, jack cr, ehman rl. magentic resonance elastography of the brain. neuroimage. 2008;39:231-237. (download)

miller k, chinzei k. constitutive modelling of brain tissue: experiment and theory. j biomech. 1997;30:1115-1121. (download)

raybaud c, widjaja e. development and dysgenesis of the cerebral cortex: malformations of cortical development. neuroimag clin n am. 2011;21:483–543. (download)

richman dp, stewart rm, hutchinson jw, caviness vs. mechanical model of brain convolutional development. science. 1975;189:18-21. (download)

sun t, hevner rf. growth and folding of the mammalian cerebral cortex: from molecules to malformations. nature neurosci. 2014;15:217-231. (download)

van essen dc. a tension-based theory of morphogenesis and compact wiring in the central nervous system. nature. 1997;385:313-318. (download)

weickenmeier j, kuhl e, goriely a. the multiphysics of prion-like disease: progression and atrophy. phys rev lett. 2018;121:158101. (download)