Experimental control in COGENT/MATLAB Christian Ruff

COGENT and MATLAB Cogent is a MATLAB-toolbox (set of functions and.dlls) that can be used for control of behavioural and neuroimaging experiments Cogent functions can: –Control timing –Display pictures –Display words –Play sounds –Collect responses –Control serial and parallel ports Cogent runs in MATLAB (so that COGENT scripts can be set up as MATLAB functions, and can access all other MATLAB functions) However, COGENT functions only run in a special ‘mode’ that has to be set up

How to obtain and run COGENT Cogent is programmed at UCL (FIL and LON ), and is freely available at All you have to do is: –download the zip-files –unpack the directory on your computer –put this directory on the MATLAB path (so that MATLAB finds the functions) Cogent at present runs with all versions of MATLAB up to 7.1, but will be updated within the next month or so to also run with more recent versions COGENT has its own excellent documentation (cogmanv125.pdf and G2UsrManv124.pdf for graphics functions) in the folder ‘Documents’ There are also many example scripts (in the folder ‘samples’)

Structure of COGENT There are two sets of COGENT-functions: –COGENT 2000: High-level functions for experimental control (covered here) –Low-level graphics functions (starting with cg*; covered in future sessions) Every COGENT script should have a certain structure: (1) (Define experimental parameters) (2) Initialise cogent (3) Start cogent (4) Execute cogent commands (5) Terminate cogent Errors can occur if (4) is attempted before (2) and (3)