Imagery and perception share cortical representations of content and location.
Cichy RM, Heinzle J, Haynes JD.
Published in Cereb Cortex. 2012 Feb;22(2):372-80.
Visual imagery allows us to vividly imagine scenes in the absence of visual stimulation. The likeness of visual imagery to visual perception suggests that they might share neural mechanisms in the brain. Here, we directly investigated whether perception and visual imagery share cortical representations. Specifically, we used a combination of functional magnetic resonance imaging (fMRI) and multivariate pattern classification to assess whether imagery and perception encode the "category" of objects and their "location" in a similar fashion. Our results indicate that the fMRI response patterns for different categories of imagined objects can be used to predict the fMRI response patters for seen objects. Similarly, we found a shared representation of location in low-level and high-level ventral visual cortex. Thus, our results support the view that imagery and perception are based on similar neural representations.
Investigating functional connectivity in visual awareness using "Mooney" images.
Imamoglu F, Kahnt T, Koch C, Haynes JD.
In this project we investigate effects of conscious recognition of visual objects on functional connectivity. For this we have developed an automated "Mooney" image generator. These binarized two-tone images are difficult to recognize at first, but can then be readily recognized. This allows to compare pre-recognition and post-recognition phases of visual processing.
Visual masking of orientation stimuli.
Imamoglu F, Kahnt T, Haynes JD.
In this project we investigate the neural mechanisms of backwards masking. For this we use orientated grating stimuli that are backward masked at various latencies. The psychophysical threshold functions are then quantitatively related to BOLD signals and to functional connectivity.