Experimental control in COGENTMATLAB

1
Experimental control in COGENT/MATLAB

• Christian Ruff

2
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

3
How to obtain and run COGENT

• Cogent is programmed at UCL (FIL and LON ), and
  is freely available at
• http//www.vislab.ucl.ac.uk/Cogent/
• 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)

4
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)