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== Visual Contrast Response Function Program ==
vb.net program
attachment:VisualResponseContrast

Participants view 10 levels of contrast in sine wave gratings presented as dynamic moving images surrounding a central fixation target spotting task (spot the target 'x' in a continuous stream of letters). 

attachment:disc.PNG [[BR]]

Stimulus is displayed for 12 secs with a 6 sec blank screen rest period (target spotting task continues throughout rest and null trials) 

== Parameters ==
A block design is used to allow for maximal HRF values and return to baseline. 
Alternate runs of the constant stimulus and adaptive procedure. 

4 epis (2 constant and 2 adaptive runs at 2.5 and 6.5 each) 
Measurements: 780[[BR]]
TR 1 (64x64 matrix, 3x3x3.75mm voxels)[[BR]]
16 slices [[BR]]
V1 ROI [[BR]]

Scanning Protocol: [[BR]]
Gre_Field mappong sequence, EPIS (4 blocks, 12 minutes, 40 trials per block), standard CBU MPRAGE sequence 

== Example of Real-Time Output ==
attachment:graph.png [[BR]]

== Bold Guided Adaptive procedure ==

A neurometric model is fitted to the data using a Bayesian procedure. The adpative procedure presents the stimuli around the contrast level of the model best describing the threshold at that point (see figure below). [[BR]]
The constant stimulus procedure presents stimuli in a randomised order, irrespective of threshold estimates. 

attachment:graphs2.png