Sharpness of vision depends on the spatial resolution conveyed by individual neurons in the visual pathway. In the dorsal lateral geniculate nucleus (LGN) neurons have receptive fields with center-surround organization, and spatial resolution may be measured as the inverse of center width. We have studied dynamics of the center width of single LGN neurons in anaesthetized cats during the response to light or dark spots presented with durations (400–500 ms) corresponding to natural inter-saccadic fixation periods. Center width was estimated from a series of spatial summation curves made for successive 5 ms intervals during the stimulation period. In nonlagged neurons the center was wide at the start of the response, but shrank rapidly over 50–100 ms after stimulus onset, whereupon it widened slightly. Thereby, the spatial resolution changed from coarse-to- fine with average peak resolution occurring transiently ~70 ms after stimulus onset. The changes in spatial resolution did not follow changes of firing rate; peak firing appeared earlier than maximal spatial resolution. We suggest that the response initially conveys a strong but spatially coarse message that might have a detection and tune-in function, followed by transient transmission of spatially precise information about the stimulus. Experiments with spots presented inside the maximum but outside the minimum center width suggested a dynamic reduction in number of responding neurons during the stimulation from many neurons responding initially to fewer ones as the centers shrink. This implies a change also in the recruitment of responding neurons. Lagged neurons, which get their initial visual response suppressed by intrageniculate inhibition, lacked the dynamic changes of receptive field organization