The nature of the quantitative relationship between single-neuron recording
s in monkeys and functional magnetic resonance imaging (fMRI) measurements
in humans is crucial to understanding how experiments in these different sp
ecies are related, yet it remains undetermined. We measured brain activity
in humans attending to moving visual stimuli, using blood oxygenation level
-dependent (BOLD) fMRI. Responses in Vs showed a strong and highly linear d
ependence on increasing strength of motion signal (coherence). These popula
tion responses in human Vs had a remarkably simple mathematical relationshi
p to previously observed single-cell responses in macaque Vs. We provided a
n explicit quantitative estimate for the interspecies comparison of single-
neuron activity and BOLD population responses. Our data show previously unk
nown dissociations between the functional properties of human Vs and other
human motion-sensitive areas, thus predicting similar dissociations for the
properties of single neurons in homologous areas of macaque cortex.