Fatima M. Felisberti

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Face recognition algorithms perform very unreliably when the pose of the probe face is different from the gallery face: typical feature vectors vary more with pose than with identity. We propose a generative model that creates a one-to-many mapping from an idealized "identity" space to the observed data space. In identity space, the representation for each(More)
In previous work, we have shown that sudden image displacements well outside the classical receptive field modulate the visual sensitivity of LGN relay cells. Here we report the effect of image displacements on the response versus contrast function. The stimuli consisted of a central spot of optimal size and polarity (contrast range: 3-98%), flashed alone(More)
Visual stimulation of zones extending beyond the classical receptive field can modulate the contrast gain of neurons in the lateral geniculate nucleus (LGN) of cats, but little is known about the effect of extra-classical visual stimulation on the LGN of primates. Hence, we compare the effect of long-range interactions in parvocellular and magnocellular LGN(More)
Human observers can extract a given motion direction from sets of random dots moving simultaneously in two or more directions in the same region of the visual field, a phenomenon referred to as motion transparency. As a necessary condition for separating transparent motion directions, low level encoding of local motion signals must generate frequency(More)
Crowding, the difficult identification of peripherally viewed targets amidst similar distractors, has been explained as a compulsory pooling of target and distractor features. The tilt illusion, in which the difference between two adjacent gratings' orientations is exaggerated, has also been explained by pooling (of Mexican-hat-shaped population responses).(More)
OBJECTIVE The study compared alcohol's effects on the recognition of briefly displayed facial expressions of emotion (so-called microexpressions) with expressions presented for a longer period. METHOD Using a repeated-measures design, we tested 18 participants three times (counterbalanced), after (i) a placebo drink, (ii) a low-to-moderate dose of alcohol(More)
Mindreading refers to the ability to attribute mental states, including thoughts, intentions and emotions, to oneself and others, and is essential for navigating the social world. Empirical mindreading research has predominantly featured children, groups with autism spectrum disorder and clinical samples, and many standard tasks suffer ceiling effects with(More)
Morphological changes in dioptric structures, in the position of screening pigments and in the microvillar arrangement of the rhabdom were observed in Atta sexdens ant ommatidia exposed to different light/dark schedules. During the day there was a funneling of the crystalline cone and the pigments were close to the rhabdom. At night the crystalline cone(More)
Clusters of dark pigmented cells, called putative cerebral extraocular photoreceptors (CEPs), are described in the optic lobes of four ant species: Atta sexdens, Camponotus rufipes, Camponotus crassus, and Pseudomyrmex adustus. Electron-micrographs of CEPs show a central rhabdom-like structure formed by tightly interleaved cells containing shielding(More)
The sudden displacement of the retinal image during a saccade raises the visual threshold of human observers to foveal stimuli. The fall in visual sensitivity observed during this phenomenon, known as saccadic suppression, seems to occur very early in the visual processing chain. The lateral geniculate nucleus (LGN) is a likely locus for the multiple(More)