Category: Reviews

• Using the SVD to estimate receptive fields

  Spatio-temporal receptive fields can be hard to visualize. They can also be quite noisy. Thus, it’s desirable to find a low-dimensional approximation to the RF that is both easier to visualize and less noisy. The SVD is frequently used in neurophysiology for this purpose. Reading the Wikipedia page on the SVD, you might have trouble…

  September 20, 2011

• Hexagonal orientation maps in V1

  Interesting paper from Se-Bum Paik and Dario Ringach in this month’s issue of Nature Neuroscience on the origins of the orientation map in V1. Dr. Ringach has been developing a model of V1 orientation selectivity for a number of years now, the statistical connectivity hypothesis, based on the idea that the retinotopic map in V1…

  July 5, 2011

• The far-reaching influence of sparse coding in V1

  Introduction Olshausen and Field (1996) made a big splash in visual neurophysiology and machine learning by offering an answer to a provocative question: Why are simple cell receptive fields (RFs) organized the way they are? After all, they could just as well be shaped like elongated sine waves, as in Fourier analysis, or they could…

  June 15, 2011