Types from physiology and anatomy Basic types of brain networks can be described in terms of physiology and anatomy a Functional brain networks: Functional connectivity: temporal correlation between spatially remote neurophysiological events(Friston, Hum Brain Mapp 2004) Effective connectivity: causal effects of one neural system over another(Friston, Hum Brain Mapp 2004) a Structural brain networks: Structural connectivity: physical or structural (synaptic)connections linking neuronal units(sporns et al., Trends Cogn Sci 2004) I Morphometric connectivity: statistical interdependencies of morphological features between different brain regions such as the cortical thickness, gray matter volumes, density, areas and complexity(He et al., Neuroscientist, 2009) 6
Types from physiology and anatomy ➢ Basic types of brain networks can be described in terms of physiology and anatomy. ❑ Functional brain networks: • Functional connectivity: temporal correlation between spatially remote neurophysiological events (Friston, Hum Brain Mapp 2004). • Effective connectivity: causal effects of one neural system over another (Friston, Hum Brain Mapp 2004). ❑ Structural brain networks: • Structural connectivity: physical or structural (synaptic) connections linking neuronal units (Sporns et al., Trends Cogn Sci 2004). • Morphometric connectivity: statistical interdependencies of morphological features between different brain regions such as the cortical thickness, gray matter volumes, density, areas and complexity (He et al., Neuroscientist, 2009). 6
Brain Network Analysis(BNA) Non-invasive technique > Imaging techniques Graph theory Medical Imaging o functional MRi diffusion tensor mri, structural mri Reveal the properties of the brain a Small world, Scale free [Heuvel 20081 口 Efficiency a Modular structure valencia 2009 Understand the mechanism of brain diseases o Alzheimer's disease [he 2008; Supekar 2008 Lo 2010 a Schizophrenia [Bassett 2008; Zalskey 2010; Liu 2008 a Depression [Zhang 2011]
Brain Network Analysis (BNA) ➢ Imaging techniques + Graph theory ❑ functional MRI, diffusion tensor MRI, structural MRI, … ➢ Reveal the properties of the brain ❑ Small world, Scale free [Heuvel 2008] ❑ Efficiency ❑ Modular structure [Valencia 2009] ❑ … ➢ Understand the mechanism of brain diseases ❑ Alzheimer’s disease [He 2008; Supekar 2008; Lo 2010] ❑ Schizophrenia [Bassett 2008; Zalskey 2010; Liu 2008] ❑ Depression [Zhang 2011] ❑ … 7 Non-invasive technique: Medical Imaging
Challenge 1: Voxel-based BNA Utilize the high resolution of imaging techniques a Compared with region-based BNA 口2mm*2mm*2mm( each pixel)国国圆图图区 图图图国 口10k~100 k voxels 0o0Y 100 Regions 100 100K Vo×els 100K
10 20 30 40 50 60 5 10 15 20 25 30 35 40 45 50 Challenge 1: Voxel-based BNA ➢ Utilize the high resolution of imaging techniques ❑ Compared with region-based BNA ❑ 2mm * 2mm * 2mm (each pixel) ❑ 10k ~ 100k voxels 8 Regions 100 Regions 100 Voxels Voxels 100K 100K
Challenge 2: Multi/Many Subjects Huge computation, 2 days/ subject o 0(n,o(n)complexity Big-0 Complexity 口 Large n a Many subjects Low Signal-to-Noise Ratio [Benjamini 2006 a Solution: Take account networks from many subjects o But, Network construction is time-consuming 9
Challenge 2: Multi/Many Subjects ➢ Huge computation, 2 days / subject ❑ 𝑂 𝑛 2 , 𝑂 𝑛 3 complexity ❑ Large n ❑ Many subjects ➢ Low Signal-to-Noise Ratio [Benjamini 2006] ❑ Solution: Take account networks from many subjects ❑ But, Network construction is time-consuming 9
What we need Computing platforms and techniques that should be 口 Efficient Huge computation a Scalable Increasing network size a Affordable(infrastructure and power) Can be used in hospitals 10
What we need ➢ Computing platforms and techniques that should be ❑ Efficient • Huge computation ❑ Scalable • Increasing network size ❑ Affordable (infrastructure and power) • Can be used in hospitals 10