English: Reproduced from the Supplementary Materials of Chen et al. (2011) "Functional mapping of single spines in cortical neurons in vivo" The first demonstration of sensory-stimulation-evoked single-spine activity in mammalian cortical neurons in vivo. The results show a wide range of frequency tuning of individual spines, with a large proportion (45%) having a bandwidth of less than one octave, even at the relatively high sound level used here, in which the electrical tuning width of the neurons was a few octaves. The movie shows three consecutive trials of spine calcium responses to pure tone stimulation (0 dB attenuation; 100 ms duration). The image data were downsampled from 1000 Hz to 80 Hz. S2 is a radial spine above the dendritic shaft.