Whole Brain Emulation A Roadmap (2008) Technical Report #2008‐3 Anders Sandberg* Nick Bostrom Future of Humanity Institute Faculty of Philosophy & James Martin 21st Century School Oxford University CITE: Sandberg, A. & Bostrom, N. (2008): Whole Brain Emulation: A Roadmap, Technical Report #2008‐3, Future of Humanity Institute, Oxford University URL: www.fhi.ox.ac.uk/reports/2008‐3.pdf (*) Corresponding author: [email protected] In memoriam: Bruce H. McCormick (1930 – 2007) 2 Contents Whole Brain Emulation............................................................................................................................1 A Roadmap ................................................................................................................................................1 In memoriam: Bruce H. McCormick (1930 – 2007)...........................................................................2 Contents..................................................................................................................................................3 Introduction ...........................................................................................................................................5 Thanks to............................................................................................................................................6 The concept of brain emulation..........................................................................................................7 Emulation and simulation...............................................................................................................7 Little need for whole‐system understanding...............................................................................8 Levels of emulation and success criteria.....................................................................................10 Scale separation...............................................................................................................................12 Simulation scales.............................................................................................................................13 WBE assumptions...........................................................................................................................15 Roadmap ..............................................................................................................................................16 Requirements...................................................................................................................................16 Linkages............................................................................................................................................19 Roadmap ..........................................................................................................................................20 Technology drivers.........................................................................................................................23 Uncertainties and alternatives......................................................................................................24 Alternative pathways.....................................................................................................................27 Related technologies and spin‐offs..............................................................................................28 Issues.....................................................................................................................................................30 Emulation systems..........................................................................................................................30 Complications and exotica ............................................................................................................31 Summary ..........................................................................................................................................39 Scanning ...............................................................................................................................................40 Embedding, fixation and staining techniques ...........................................................................52 Conclusion .......................................................................................................................................53 Image processing and scan interpretation......................................................................................55 Geometric adjustment....................................................................................................................55 Noise removal .................................................................................................................................56 Data interpolation...........................................................................................................................56 Cell tracing.......................................................................................................................................57 Synapse identification....................................................................................................................59 Identification of cell types .............................................................................................................60 Estimation of parameters for emulation.....................................................................................61 Connectivity identification............................................................................................................62 Conclusion .......................................................................................................................................63 Neural simulation...............................................................................................................................64 How much neuron detail is needed?...........................................................................................64 Neural models.................................................................................................................................66 Simulators ........................................................................................................................................70 Parallel simulation..........................................................................................................................70 Current large‐scale simulations....................................................................................................71 Conclusion .......................................................................................................................................72 Body simulation ..................................................................................................................................74 Conclusion .......................................................................................................................................75 Environment simulation....................................................................................................................76 3 Vision ................................................................................................................................................76 Hearing.............................................................................................................................................77 Smell and Taste ...............................................................................................................................77 Haptics..............................................................................................................................................77 Conclusion .......................................................................................................................................78 Computer requirements ....................................................................................................................79 Conclusions......................................................................................................................................81 Validation.............................................................................................................................................82 Discussion ............................................................................................................................................83 Appendix A: Estimates of the computational capacity/demands of the human brain ..........84 Appendix B: Computer Performance Development ....................................................................86 Processing Power............................................................................................................................86 Memory ............................................................................................................................................95 Disc drives........................................................................................................................................97 Future................................................................................................................................................98 Appendix C: Large‐scale neural network simulations...............................................................101