Silvio P. Sabatini

Learn More
Interacting in the peripersonal space requires coordinated arm and eye movements to visual targets in depth. In primates, the medial posterior parietal cortex (PPC) represents a crucial node in the process of visual-to-motor signal transformations. The medial PPC area V6A is a key region engaged in the control of these processes because it jointly processes(More)
A variety of computational tasks in early vision can be formulated through lattice networks. The cooperative action of these networks depends on the topology of interconnections, both feedforward and recurrent ones. This paper shows that it is possible to consider a distinct general architectural solution for all recurrent computations of any given order.(More)
Eye position signals are pivotal in the visuomotor transformations performed by the posterior parietal cortex (PPC), but to date there are few studies addressing the influence of vergence angle upon single PPC neurons. In the present study, we investigated the influence on single neurons of the medial PPC area V6A of vergence and version signals.(More)
A new approach to analog VLSI implementations of algorithms for visual cortical processing is presented. Speciically, we introduce a massively parallel architecture , organized as a planar resistive network with voltage controlled current generators locally connected to model interaction schemata responsible of speciic sensitivities in cortical neurons. We(More)
A continuous-space model of visual cortex interactions which, starting from elongate Gaussian functions, leads to high-selective Gabor-like receptive fields, is proposed. The model is based on intracortical inhibition mechanisms occurring through medium-range clustered connections. The analysis, carried out under the assumption of a linear superposition of(More)
Within a linear field approach, an architectural model for simple cell direction selectivity in the visual cortex is proposed. The origin of direction selectivity is related to recurrent intracortical interactions with a spatially asymmetric character along the axis of stimulus motion. No explicit asymmetric temporal mechanisms are introduced or adopted.(More)
A perceptual human-machine interface based on visual appearance of hand movements is presented. Gestures are defined as the temporal evolution of 3D poses the of user's hand. Each gesture is described by five temporal sequences corresponding to the time evolution of the stereo depth information at the finger-tips. To this end feature processing directly(More)
The problem of representing the visual signal in the harmonic space guaranteeing a complete characterization of its 2D local structure is investigated. Specifically, the efficacy of anisotropic versus isotropic filtering is analyzed with respect to general phase-based metrics for early vision attributes. We verified that the spectral information content(More)
A computational model for the control of horizontal vergence, based on a population of disparity tuned complex cells, is presented. Since the population is able to extract the disparity map only in a limited range, using the map to drive vergence control means to limit its functionality inside this range. The model directly extracts the disparity-vergence(More)