262013-03-07 21:20:04localhostconverted to 1.6 markup252009-06-12 14:51:38MicheleVeldsman242009-06-12 11:49:09MicheleVeldsman232009-06-12 11:46:41MicheleVeldsman222009-05-14 14:34:07MicheleVeldsman212009-05-14 14:33:51MicheleVeldsman202009-05-14 14:25:38MicheleVeldsman192009-05-14 14:23:19MicheleVeldsman182009-05-14 14:04:21MicheleVeldsman172009-05-14 13:58:22MicheleVeldsman162009-05-14 13:47:27MicheleVeldsman152009-05-14 13:46:12MicheleVeldsman142009-05-14 13:45:16MicheleVeldsman132009-05-14 13:43:49MicheleVeldsman122009-05-14 13:42:29MicheleVeldsman112009-05-14 13:40:28MicheleVeldsman102009-05-14 13:39:44MicheleVeldsman92009-05-13 10:46:33MicheleVeldsman82009-05-12 12:47:57MicheleVeldsman72009-05-12 12:46:50MicheleVeldsman62009-05-12 12:43:38MicheleVeldsman52009-05-11 14:59:06MicheleVeldsman42009-05-11 14:58:27MicheleVeldsman32009-04-30 12:53:04MicheleVeldsman22009-04-30 10:04:49MicheleVeldsman12009-04-29 13:39:53MicheleVeldsman

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

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 TR 1 (64x64 matrix, 3x3x3.75mm voxels) 16 slices V1 ROI Scanning Protocol: Gre_Field mappong sequence, EPIS (4 blocks, 12 minutes, 40 trials per block), standard CBU MPRAGE sequence

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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). The constant stimulus procedure presents stimuli in a randomised order, irrespective of threshold estimates. graphs2.png