0000000000324543
AUTHOR
Alessandro Carlini
Visual tracking combined with hand-tracking improves time perception of moving stimuli
A number of studies have shown that performing a secondary task while executing a time-judgment task impairs performance on the latter task. However, this turns out not to be the case for certain motor secondary tasks. We show that concomitant secondary motor tasks involving pointing, when performed during a time-judgment task, can actually improve our time-judgment abilities. We compared adult participants' performance in a time-of-movement paradigm with visual pursuit-only and with visual pursuit plus hand pursuit. Rather than interfering with their estimation of stimulus movement duration, the addition of hand pursuit significantly improved their judgment. In addition, we considered the …
Motion perception in early glaucoma
Purpose: The aim of our study was to underline the changes in the movement perception for early glaucoma. Our working hypothesis consisted in inquiring if the impairment of the magnocellular pathway may modify the movement perception capabilities in the visual field, more particularly in its peripheral area.Methods: We included 14 healthy subjects and 14 patients with early primary open angle glaucoma. A moving target was presented on a semicircular screen (1.8 m diameter); participants were asked to localize the Ending Point (EP) of each movement. Each stimulus consisted in a white dot (0,72° of diameter) moving horizontally with the imposed velocity profile. Two different laws of motion w…
Analysis of HMAX Algorithm on Black Bar Image Dataset
An accurate detection and classification of scenes and objects is essential for interacting with the world, both for living beings and for artificial systems. To reproduce this ability, which is so effective in the animal world, numerous computational models have been proposed, frequently based on bioinspired, computational structures. Among these, Hierarchical Max-pooling (HMAX) is probably one of the most important models. HMAX is a recognition model, mimicking the structures and functions of the primate visual cortex. HMAX has already proven its effectiveness and versatility. Nevertheless, its computational structure presents some criticalities, whose impact on the results has never been…
When Geometry Constrains Vision: Systematic Misperceptions within Geometrical Configurations.
International audience; How accurate are we in reproducing a point within a simple shape? This is the empirical question we addressed in this work. Participants were presented with a tiny disk embedded in an empty circle (Experiment 1 and 3) or in a square (Experiment 2). Shortly afterwards the disk vanished and they had to reproduce the previously seen disk position within the empty shape by means of the mouse cursor, as accurately as possible. Several loci inside each shape were tested. We found that the space delimited by a circle and by a square is not homogeneous and the observed distortion appears to be consistent across observers and specific for the two tested shapes. However, a com…
Misidentification Delusions : prevalence in different types of dementia and validation of a structured Questionnaire
International audience; Misidentification delusions (MDs) are considered relatively rare psychopathologic phenomena that may occur within the context of psychiatric or neurological conditions. The purpose of this study was to assess the prevalence of MD in different types of dementia, correlate the presence of MD with demographic and clinical variables, and validate a specific questionnaire. We examined 146 subjects with Alzheimer disease, 21 with Lewy body dementia, 6 with frontotemporal dementia, and 13 with vascular dementia (subcortical type), who were consecutively enrolled in the study from 2 Memory Clinics. Patients had a mean age of 78.7±6.4 years and an Mini-Mental State Examinatio…