Encoding of 3D Structure in the Visual Scene: A New Conceptualization
The multidisciplinary goal was to develop an integrated conceptualization of the mid-level encoding of 3D object structure from multiple surface cues. Psychophysical studies showed that depth continuity is a prerequisite for facilitation of Gabor target detection in the context of flanking Gabors, and that, similarly, surface continuity in purely disparity-defined slanted surfaces was strongly enhanced in distributed patch detections as a function of stimulus duration in this dual discrimination task. The unprecedented dips of performance reduction in the component psychometric functions was captured in a computational model based on a novel Leaky Drift Diffusion Theory that we developed for the underlying neural signals, which can serve as an analytic basis for the time course of all neural decision processes. The time course of depth surface perception was studied in a coordinated trio of psychophysical, neurophysiological and functional imaging studies, showing that the perceptual processing of disparity and integration of 3D surface information across depth cues has time courses of several seconds, attesting to complexity of the neural processing hardware. Three complementary computational modeling projects from three collaborating laboratories showed how surface reconstruction could be accomplished across the typically sparse depth information available, and integrated among sparse, incommensurate cue modalities. The team was led by the lead PI Prof. Christopher Tyler (Smith-Kettlewell); a PI on the Subcontract with Carnegie Mellon University was Prof. Tai-Sing Lee.
Smith-Kettlewell Brain Imaging CenterRead More
The Smith-Kettlewell Brain Imaging Center supports a wide variety of human brain imaging modalities, including MRI, MRI morphometry, functional MRI, fMR Iretonogrphy, fMRI dynamics, functional connectivity, Granger-causal connectivity, DTI, DTI tractography, whole-head EEG, EEG functional connectivity, ERG, EEG eye tracking, electroblepharography, etc. Our work centers on human visual neuroscience and computational vision, especially in the areas of human visual processing in adults, of the diagnosis of eye diseases and cortical deficits in infants and adults, on brain plasticity in relation to low vision and blindness, and on the processes of blindness rehabilitation. We are particularly interested in the normal capabilities of binocular visual processing and its disruption by forms of traumatic brain injury.
Likova LabRead More
The main areas of my research are learning and brain plasticity of multimodal sensorimotor processing in the blind and the sighted.
- Christopher Tyler - Head, Smith-Kettlewell Brain Imaging Center
- Lora Likova - Senior Scientist, Likova Lab Director
- Spero Nicholas - Senior Programmer-Analyst