Ken Miller's math notes: Linear Algebra for Theoretical Neuroscience

These are some notes I've written to try to teach linear algebra and related aspects of linear differential equations to students of theoretical neuroscience. I've also included a nice set of notes written by Philip (Flip) Sabes of UCSF when we were co-teaching a course; these are best read after Part 3. Most neuroscience students seem to find they never make it through Part 4, which is on the Fourier transform -- too much detail and too little motivation -- but the rest seems to work reasonably well in getting the conceptual ideas across to motivated biologists who don't have much background. Part 4 stands alone, and can be omitted, but read it if you'd like to better understand the Fourier transform and in particular understand that it is just another coordinate transformation (a particular one that diagonalizes a particular set of matrices or linear operators and hence is used particularly often).

Although these notes work reasonably well -- particularly if they're used in or followed by a course in which the ideas are used in the context of real biological problems -- they also leave a lot to be desired. They need many more figures, many more neuroscience examples, and more and better problems. I'd also like to include an introductory chapter reminding people of basics of 1-dimensional linear differential equations and the exponential function, before heading into multiple dimensions. I'd like to include some chapters on probability, and in particular on Poisson and Gaussian distributions (and the linear algebra leads naturally to understanding multi-dimensional Gaussian distributions). At that point, it would probably become "Mathematics for Theoretical Neuroscience" rather than "Linear Algebra for Theoretical Neuroscience". Part 3, which deals with non-normal matrices -- matrices that do not have a complete orthonormal basis of eigenvectors -- needs to be completely rewritten: since it was written, I've learned that non-normal matrices have many features not predicted by the eigenvalues that are of great relevance in neurobiology and in biology more generally, and the notes don't deal with this (in the meantime, for the mathematical aspects, see the book by L.N. Trefethen and M. Embree, Spectra and Pseudospectra: The Behavior of Nonnormal Matrices and Operators. Princeton University Press, 2005). And Part 4 runs out of steam where I start talking about the connections between vectors and functions, matrices and linear operators, Kronecker deltas and Dirac deltas, and even more where it talks about multi-dimensional Fourier transforms. This all needs more work. Just haven't had the time. If you are interested in taking on any of these projects, particularly (but not limited to) figures, examples, or problems, or in adding other useful pieces of mathematics, let me know. Perhaps we can collaboratively build a useful resource.

All feedback on making these notes better will be appreciated. I'm not certain when I'll have time to implement them, but hope to.

I'd be very happy if you linked to this page. I'd prefer you link rather than posting the material yourself, both because (1) that way the creative commons license stays with the material and (2) that way people are always pointed to the latest versions, in case I should find the time to update. Here are the notes:
And here's Flip Sabes' notes on linear algebraic equations, SVD, and the pseudo-inverse: Creative Commons License
Linear Algebra for Theoretical Neuroscience by Kenneth D. Miller is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.
Linear Algebraic Equations, SVD, and the Pseudo-Inversee by Phillip N. Sabes is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.
Ken Miller
Last modified: Thu Aug 28 11:45:45 EDT 2008