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Abstract:
Nine subjects (seven male, two female) participated in a
functional magnetic resonance imaging study of a continuous
performance task. The purpose of the study was to identify brain
regions involved in response inhibition. Coregistered anatomical
and functional images were acquired on a 1.5 Tesla General Electric
scanner in twelve 10-millimeter slices with 0-millimeter offset.
The seventh slice superior to inferior was aligned with the
bicommissural axis. High-resolution anatomical images were
collected using a spoiled-GRASS pulse sequence (field of view = 24
cm, matrix = 256 x 256 millimeters). Functional images were
collected using a gradient-echo echo-planar sequence (TR = 1
second, TE = 40 milliseconds, field of view = 24 cm, matrix size =
64 x 64 millimeters, slice thickness = 10 millimeters skip 0).
Letters were pseudorandomly presented for 250 milliseconds at a
rate of one per second. The subject was instructed to press a
button with the right index finger every time a letter appeared,
unless the letter was ìxî. The data were convolved
with a hemodynamic response function to determine areas activated
when subjects were required to inhibit responding. The left caudate
was activated, suggesting that it is critically involved in
response inhibition.
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