On Mon, 8 Oct 2018 at 14:10, Alyson Saenz <neuro.aly...@gmail.com> wrote:
> Does anyone know a paper in which someone has explored the effect of > different searchlight radius? > > I know that a bigger radius increases performance but also processing > time, and that at some point you will get bad performances, but, has anyone > systematically explored this? > In addition to Yarik's and Jo's great suggestions and observations, let me add: - In general, the optimal radius would depend on the spatial extent and distributed nature of the effect of interest. Different neural mechanisms may have a different spatial distribution / scale. - the original paper by Kriegeskorte et al (2006): "For the information-based analysis, we chose a searchlight radius of 4 mm, because this radius yielded the best detection performance in the simulation". In my experience, such small radii are not common these days; most studies report larger radii, typically 6-12 mm . - with shameless self-promotion, there is a paper [1] possibly useful for surface-based approaches. Note that the analyses focused in M1 and S1 regions with discrimination of different digits (fingers); your mileage may vary with different tasks or brain regions. [1] Oosterhof, Nikolaas N., et al. "Surface-based information mapping reveals crossmodal vision–action representations in human parietal and occipitotemporal cortex." *Journal of Neurophysiology* 104.2 (2010): 1077-1089.
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