Temporal evolution of the CBV-fMRI signal to rat whisker stimulation of variable duration and intensity: a linearity analysis.
Cerebral blood volume functional magnetic resonance imaging (CBV-fMRI) experiments employing iron oxide contrast agent were conducted in rat whisker barrel cortex at 3 Tesla. Stimuli of constant frequency (12 Hz) but variable duration and intensity were delivered separately using a homemade whisker stimulator. The temporal behavior of CBV-fMRI signals was investigated using a linearity analysis method. Both superposition and scaling tests show that CBV-fMRI responses are generally consistent with a linear time-invariant (LTI) model. In particular, the response to a stimulus of higher intensity can be linearly scaled from that of lower intensity. However, significant deviations exist when the stimulus duration is manipulated, particularly in the trailing edge of the CBV-fMRI response curves.
Lu
Hanbing
H
Department of Biophysics, Medical College of Wisconsin, Milwaukee, 53226, USA.
Soltysik
David A
DA
Ward
B Douglas
BD
Hyde
James S
JS
D000818:Animals; D001810:Blood Volume / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003287:Contrast Media; D003627:Data Interpretation, Statistical; D005290:Ferric Compounds; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014738:Vibrissae / Q000502:physiology*
D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide