Speed-dependent motion-sensitive responses in V5: an fMRI study.
This fMRI study examined motion-sensitive responses in human area V5 as a function of stimulus speed. Consistent with electrophysiological findings, we observed optimal responses at intermediate speeds of around 7 degrees/s to 30 degrees/s. The results are consistent with a nonlinear (inverted "U") dependency on speed that was also observed in V3a. V1 activation was observed to decrease linearly as speed increased. This is consistent with the fact that speed-sensitive cells in V1 have been shown to be tuned to much slower speeds than in V5.
Chawla
D
D
Leopold Muller Functional Imaging Laboratory, Wellcome Department of Cognitive Neurology, Institute of Neurology, London, UK. dave@fil.ion.ucl.ac.uk
Phillips
J
J
Buechel
C
C
Edwards
R
R
Friston
K J
KJ
D001921:Brain / Q000502:physiology*; D003463:Cues; D003627:Data Interpretation, Statistical; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009039:Motion Perception / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology*; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*