Visual psychophysics and modelling of contextual effects in orientation and motion perception
Final Report Abstract
Observations about visual perception together with the accumulated knowledge in neurophysiological organisation of brain areas have led scientists to hypothesise similarities in visual signal processing of various features. Based on psychophysical knowledge in contextual perception of orientation and direction of motion, and the similarities in the processing of these features in their distinct visual areas, it was investigated whether a single theoretical framework of circular feature processing could explain the similarities and differences in contextual modulations of orientation and motion direction perception. The project aimed at measuring the effects on two behavioural probes, perception of weak and strong target signal, together with proposing a unique model for explaining their modulation by the presence of context. The study demonstrated how the similarities are well explained through a simplified model of neuronal organisation coding a circular feature, which includes only surround-to-center inhibitory interactions, and how the differences between the two features arise from different population characteristics, obtained through model fits to the behavioural results. The project main result allows a simpler understanding of coding and decoding circular features as orientation and motion direction and the observed effects in visual perception through the implementation of a unique theoretical framework for their processing. Supplementary tests would allow a more detailed mapping of the contextual interactions together with comparing other contextual parameters onto perceptual outcome on circular features, and extension of the theoretical framework to other kinds of feature processing must be tested.
Publications
- (2012) A single theoretical framework for circular features processing in humans: orientation and direction of motion compared. Frontiers in Computational Neuroscience 6:28
Tzvetanov T
(See online at https://doi.org/10.3389/fncom.2012.00028)
