All senses provide simultaneous information about our environment and this information needs to be combined into a single percept.
The focus of the activity of the lab is the study of unimodal visual, tactile and auditory perception in humans their multimodal integration.
We principally investigate the integration between visual and tactile signals with the goal of understanding the rules that govern the merging
of perceptual information mediated by the intention to move signals and prior knowledge. Such aspects are relevant for the understanding of human perception as well as for the implementation of artificial systems. Furthermore the interest of our research is extended at the analysis of the dynamic of these perceptual capacities during development in normally sight children and considering patients with visual disabilities.
- Visual and tactile motion perception.
- Development of cross modal integration.
- Facilitation and of haptic information on visual perception
- Motion perception in low vision patients.
Visual and tactile motion perception
The principal aim of this project is to investigate the similarities between visual, tactile and bimodal perception of tactile, optic and bimodal flow. We study with psychophysical techniques unimodal and bimodal velocity discrimination thresholds for flow perception with real wheels etched with a sinewave profile of different spatial frequencies. Our system gives us the possibility to drive each wheel at a specific velocity and to create conflictual stimulation between the two modalities (Gori et.al. 2008). With this project we can answer many questions related to the analysis of unimodal visual tactile and multimodal flow perception and give us the possibility to investigate if a supramodal system of analysis may be present.
References
Gori, M., Sandini, G., Burr, D.C. (2008). “Dipper function” for bimodal and unimodal visual and tactile motion discrimination and facilitation between modalities. Cue combination Workshop Germany October.
Gori, M., Sandini, G., Burr, D.C. (2008). Visual, tactile and visuo-tactile motion discrimination. VSS (Vision Science society) International Annual Meeting.
Gori, M., Sandini,G., Burr, D.C. (2008). Motion discrimination of visual, tactile and bimodal stimuli. Hamburg 14-16 July.
Gori, M., Sciutti, A., Jacono, M., Sandini, G., Burr, D.C. (2008). Perception of acceleration and deceleration in visual, tactile and visuo-tactile stimuli. ECVP 2008, Utrecht.
Gori, M., Sciutti, A., Jacono, M., Sandini, G., Burr, D.C. (2008). Visual, tactile and visuo-tactile perception of acceleration and deceleration. IMRF 2008 Hamburg 14-16 July.
Gori, M., Sciutti, A., Jacono, M., Sandini, G., Burr, DC. (2009). "Visual, tactile and visuo-tactile perception of acceleration and deceleration." in preparation for Journal of Neuroscience.
Gori, M. S., Giulio & Burr, David C. (2008). "Visual, tactile and visuo-tactile motion discrimination." J. Vis. 8(6): 173-173.
Development of cross modal integration
The principal aim of this study is to investigate how children integrate multimodal cues. Recent studies show that the human brain integrates information across the different senses and this integration has been shown to be to be statistically optimal in adults. At what age do children start to integrate sensory signals to obtain a more robust perception, and is this integration optimal? In our laboratory we are studying the properties of the development of this ability. In our past studies we showed that prior to eight years of age, integration of visual and haptic spatial information is far from optimal, with either vision or touch dominating totally, even in conditions where the dominant sense is far less precise than the other. By eight-ten years, the integration becomes statistically optimal, like adults (Gori et.al. Current Biology, 2008).
In line with this kind of study we are also investigating how different ability and their multimodal integration develop during childhood by using different kind of real objects and by extending the study in children with different disabilities.
References
Burr, D., Binda, P. &Gori, M. (2009). Combining information from different senses: dynamic adjustment of combination weights, and the development of cross-modal integration in children. Sensory Cue Integration, Oxford Press in preparation.
Burr, D. C., Gori, M. (2009). Multisensory integration develops late in humans. in preparation for Frontiers in the Neural Bases of Multisensory Processes, Micah M. Murray & Mark T. Wallace.ori, M., M. Del Viva, et al. (2008). "Young children do not integrate visual and haptic form information." Curr Biol 18(9): 694-8.
Gori, M., Del Viva, M.M, Sandini, G., Burr, D.C. (2007). Five and six-year-old children do not integrate visual-haptic information optimally. IMRF Sydney, Sydney Australia 2007.
Gori, M., Del Viva, M.M, Sandini, G., Burr, D.C. (2008). "Young Children Do Not Integrate Visual and Haptic Form Information." Current Biology.
Gori, M. D. V., M.M.; Sandini, G.; Beccani, L.; Burr, D. (2007). Integration of information between senses develops late in humans. ECVP, Arezzo Italy.
Gori, M. D. V., M.M.; Sandini, G.; Burr, D. (2007). Six-year-old children do not integrate visual-haptic information optimally. VSS (Vision Science society) International Annual Meeting 2007, Sarasota USA.
Facilitation and of haptic information on visual perception
The principal aim of this study is to investigate the interaction between modalities. In particular we study the visual and tactile cross modal facilitation. Much recent evidence has demonstrated near-optimal integration across senses, but it remains unclear whether the integration occurs at a “sensory” or “decisional” level. The most interesting result that we found is that a tactile pedestal facilitated visual motion discrimination and vice versa, indicating facilitation between modalities. I some our experiments we show that a non-informative “pedestal” motion stimuli in one sensory modality (vision or touch) selectively lower thresholds in the other, to the same degree as pedestals in the same modality: strong evidence for functionally important cross-sensory integration at early levels of sensory processing. Studies on monkey and humans show that the cortical areas MT and MST and their human equivalents could be good candidates for the neural substrate of visual and tactile motion processing.
References
Burr, D., Gori M, Sandini G (2009). Cross facilitation of visual and haptic motion. VSS (Vision Science society) International Annual Meeting 2009, Naples USA.
Gori, M., Sandini G., Burr DC. (2009). "Cross-modal facilitation of vsiual and tactile motion." Submitted to Journal of Neuroscience.
Gori, M., Sandini, G., Burr, D.C. (2008). “Dipper function” for bimodal and unimodal visual and tactile motion discrimination and facilitation between modalities. Cue combination Workshop Germany October.
Gori, M. S., Giulio & Burr, D. C. (2008). A characteristic "dipper function" for bimodal and unimodal visual and tactile motion discrimination and facilitation between modalities. ECVP 2008, Utrecht.
Gori, M. S., Giulio & Burr, D. C. (2008). Dipper function" for bimodal and unimodal visual and tactile motion discrimination and facilitation between modalities. Cue combination Workshop Germany October 2008.
Motion perception in low vision patients
Perception of the spatio-temporal properties of the environment is essential for everyday life and anomalies related to motion perception have recently been observed in low vision people.
In this project we study in low vision patients motion perception by measuring thresholds with gratings and dots in motion (i.e. as a function of spatial frequency, luminance, speed etc..). Since we found cross modal facilitation we also propose to study tactile perception of motion and the presence of cross modal facilitation in this kind of patients.
