PMC3350955_01
Experimental design. Drawing was investigated in a three-phase paradigm consisting of a memory-guided drawing task, abbreviated as "MemoryDraw" (MD), plus two control tasks: a motor and "negative" memory control task "Scribble" (S), and a task of perceptual exploration and memorization of the model to be drawn "Explore/Memorize" (E/M). Each task duration was 20 s, with 20 s rest intervals elapsing between the tasks, with the whole trial sequence being repeated 12 times in each scanning session.
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F2
We used a three-task block paradigm, with interleaved baseline conditions (Figure 2). The dashed lines and the error bars represent confidence intervals for two different forms of statistical comparison of the activation levels (i.e., of the beta weights for the event types in the GLM): (1) The dashed lines represent the 99% "zero" confidence interval (p < 0.01, uncorrected) within which the activation amplitudes are not significantly different from zero (i.e., relative to the noise variance for no stimulus-related activation defined as the residual variance after the GLM model fit of the FMRI time course analyses section described above); thus this statistical criterion is designed to indicate the significance of each individual activation (at p < 0.05, corrected for multiple applications within each figure); (2) The error bars are "difference" confidence intervals designed to illustrate the t-test for the significance of differences between activation levels in each figure (i.e., the differences are not significant unless they exceed the confidence intervals for both compared activations), again at p < 0.05 (corrected for multiple applications).
Raised-line drawing models. Realistic faces and objects explored by the subject using her left hand in the E/M task were drawn from memory in the MD task after a 20 s rest interval. Two repetitions of each of the six stimuli were run in each fMRI session for total of 12 runs per session.
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F3
A battery of raised-line models of faces and objects was developed as the drawing targets (Figure 3).
A subject on the scanner bed operating our novel multimodal MRI-compatible drawing device. The plexiglass gantry supports a drawing tablet while a fiber-optic drawing stylus captures and records the drawing movements with high precision. The motion capture information synchronized with the fMRI allows the effect of behavioral events to be analyzed.
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F4
This system (Figure 4) incorporates a dual-slot drawing tablet that is height/distance adjustable and an adapted version of a fiber-optic device for motion-capture of the drawing movements.