Heeger DJ, Huk AC, Geisler WS, & Albrecht DG, Spikes versus BOLD: what does neuroimaging tell us about neuronal activity? Nature Neuroscience, 3:631-633, 2000.
Abstract: By demonstrating that fMRI responses in human MT+ increase linearly with motion coherence and comparing these responses with slopes of single-neuron firing rates in monkey MT, a new paper provides the best evidence so far that fMRI responses are proportional to firing rates.