The superior colliculus (SC) is a midbrain structure that integrates visual, somatosensory and auditory inputs to direct head and eye movements. Each of these modalities is topographically mapped and aligned with the others to ensure precise behavioral responses to multimodal stimuli. While it is clear that neural activity is instructive for topographic alignment of inputs from the visual cortex (V1) and auditory system with retinal axons in the SC, there is also evidence that activity-independent mechanisms are used to establish topographic alignment between modalities. Here, we show that the topography of the projection from primary somatosensory cortex (S1) to the SC is established during the first postnatal week. Unlike V1-SC projections, the S1-SC projection does not bifurcate when confronted with a duplicated retinocollicular map, showing that retinal input in the SC does not influence the topography of the S1-SC projection. However, S1-SC topography is disrupted in mice lacking ephrins-As, which we find are expressed in graded patterns along with their binding partners, the EphA4 and EphA7, in both S1 and the somatosensory recipient layer of the SC. Taken together, these data support a model in which somatosensory inputs into the SC map topographically and establish alignment with visual inputs in the SC using a gradient-matching mechanism.

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We report on a new technique for the estimation of the total rotational velocity of a non-cooperative target using a single interferometric ISAR system. It uses 3D interferometric ISAR techniques to obtain a first estimate of the scatterers' positions and effective rotation vector. Then the second-order local polynomial Fourier transform (LPFT) is applied to estimate the second component of the total rotation vector, and therefore the total vector itself. The true three-dimensional size and shape of a target - an important metric for automatic target recognition - can thus be estimated. Cross-range resolution in the 2D ISAR images is also improved in the process