These accuracy scores were determined by correct answers of locations or object identities based on button presses that indicated responses to text that accompanied the pictures. The cut off for head motion was set as 2 mm. Each participant’s data were examined for continuous motion,
intermittent spikes, and drifts in x, y, and z directions Inhibitors,research,lifescience,medical after the realignment step during data preprocessing. In addition, the Artifact Detection Tools (ART) software was used to identify global mean signal intensity and motion outliers (Gabrieli Lab, 2009; Whitfield-Gabrieli, Mozes, & Castanon, MIT). Yet, another step was to measure the temporal signal-to-noise ratio of each Inhibitors,research,lifescience,medical participant’s data and a minimum cut off was kept at 40. Thus, the decision to not include a subject’s data in the group analysis was made by taking into consideration all these aspects. Materials The
stimuli were created using grey-scale photographs of a series of small common household objects against a black background. The objects generally fit into the categories of miniature animals, children’s toys, kitchen objects, and clothing items. Each Inhibitors,research,lifescience,medical stimulus presented in the experiment was unique and the presentation of the blocks was pseudorandomized with two tasks (four blocks of object recognition and four blocks of location detection) and a fixation baseline. In the object task, participants recognized a given object and chose the appropriate name for it from a list of four alternatives, and in the location detection task, they detected the location of a given object relative to a cross at the center Inhibitors,research,lifescience,medical of the screen. The objects were positioned in four possible locations (left, right, above, and below) relative to the cross. Participant responses
were recorded using fiber optic buttons. The recorded responses provided the reaction time and performance accuracy data for the object and location tasks. For both tasks, each item was presented for 6 sec during which the participant Inhibitors,research,lifescience,medical chose the correct Farnesyltransferase answer. Each block consisted of six pictures with an interstimulus interval of 1 sec (see Fig. 1). Figure 1 A pictorial representation of the selleckchem timing of the trials and the types of stimuli and conditions presented in the study. Data acquisition and analysis All participants practiced the experiment on a laptop computer before the scanning session started. While in the scanner, the software E-Prime 1.2 (Psychology Software Tools, Pittsburgh, PA) was used to present the stimuli. An IFIS (Integrated Functional Imaging System, Invivo Corporation, Orlando, FL) interface projected the data onto a screen behind the participant’s head that was viewed using a mirror. Images were acquired using a 3T Siemens Allegra head-only scanner (Siemens Medical Inc.