
CRCNS data set pvc1 by Ringach lab – getting something to work
*Now with some 2011 updates* In a few months, our lab will be doing permanent implant recordings in V4, and analyzing this data will be a major challenge. In contrast to single electrode recordings, the stimuli used for array recordings is usually not optimized for a given cell (say, so that the stimulus is centered […]

CRCNS data sharing website
Here’s a great initiative from computational neuroscience people at Berkeley, the CRCNs data sharing website, where you can download spike trains in response to complex spatiotemporal stimuli in V1 of cats and monkeys, auditory cortex, and more. Great datasets to test your machine learning and computational skills on.

Log determinant of positive definite matrices in Matlab
In Bayesian data analysis, the log determinant of symmetric positive definite matrices often pops up as a normalizing constant in MAP estimates with multivariate Gaussians (ie, chapter 27 of Mackay). Oftentimes, the determinant of A will evaluate as infinite in Matlab although the log det is finite, so one can’t use log(det(A)). However, we know […]

Getting the steerable pyramid toolbox to work in Matlab 2008a
For whatever reason, Matlab 2008a doesn’t like the mex files that come with the steerable pyramid toolbox. If you try to recompile the mex files with Matlab’s builtin compiler, you will find that it crashes whenever you call buildSpyr. You can do the following to get it to work: Install Visual C++ express edition. Restart […]

Fast data smoothing using a running average
In the lab, we preprocess eye position data using a running average. We previously used the matlab smooth function, with the ‘moving’ argument. This matlab function implements very generic data smoothing, and is therefore unoptimized and slow. You can download a better running average function from matlab central called runmean. For a window size of […]

A case study in PsychToolbox
Although PsychToolbox is very easy to get up and running, implementing a full experiment takes time. PsychToolbox is a toolbox, not a framework; there are no constraints on how you should organize your programming. If your programming is wellorganized, it’s easy to modify your experiments, understand how a program works after you haven’t touched it […]