Neurobiology. In the article “The effect of dynamic synapses on spatiotemporal receptive fields in visual cortex” by Ömer B. Artun, Harel Z. Shouval, and Leon N. Cooper, which appeared in number 20, September 29, 1998, of Proc. Natl. Acad. Sci. USA (95, 11999–12003), the legend for Fig. 4 was printed incorrectly. The legend should read as follows:

Fig. 4. Reverse correlation functions (kernels) for the two models. (A) Kernel for SE model. (B) Kernel for the PR model. Both kernels are extracted from stimuli presented at 50 Hz. C and D are cross-sections taken from A and B at different orientations, respectively. Zero-crossings (the time at which the value of the kernel is zero) vary with orientation for the PR model but are constant in the SE model.