My Ph.D. is in physics. Through my specialization in low-temperature physics, I became involved in a particular application: the development of an extremely sensitive device for recording and precisely localizing human brain activity through measurements of the magnetic fields it generates outside the scalp. Under the supervision of Sam Williamson (a physicist) and Lloyd Kaufman (an experimental psychologist) I used an array of superconductive sensors (SQUID) to study the habituation of human auditory primary and association cortex. I found that the time constant of the psychophysical measured memory for the loudness of a sound correlates exactly with the habituation time constant of the primary auditory cortex. I also studied the human occipital alpha rhythm: We found evidence it arises from a parade of neural excitations at different locations that individually grow and subside in strength in about half a second.

Having strayed this far into psychophysics in the course of my thesis, I decided to do a post-doc with George Sperling to seriously study attention and visual perception, and to learn how to apply the quantitative and theoretical methods I learned in physics to the study of brain processes. In 1996, I joined the University of Southern California, Los Angeles, as an assistant professor with appointment in Psychology and Neural, Informational and Behavioral Sciences. At USC, I established a psychophysics laboratory. I am also collaborating with people in brain imaging to coordinate with the psychophysics. The following list covers the major research topics I have been and/or am still working on:

1. Attention: Is there a feature-based attention mechanism? What are the limitations of the attentive processes? How does selective attention select? And what are the mechanisms attention affects perceptual/cognitive processes?
2. Perceptual Learning: What are the mechanisms of perceptual learning?
3. Motion Perception: What is the functional architecture of human visual motion perception? What are the contrast-gain control mechanisms for various motion systems? How do high level cognitive processes influence motion perception? How to demonstrate that different motion systems are supported by different neural substrates? What are the mechanisms for velocity perception?
4. Texture/Pattern Recognition: What is the dimensionality of texture space? What are the fundamental texture mechanisms and their interactions? How to characterize the internal representation of visual patterns?
5. Visual Neural Network: How can a neural network, without guidance, acquire knowledge of the visual environment, and more generally, of any environmental regularities? Can we characterize the evolution of the visual system with reiteration of one single principle: structure discovering at various hierarchical levels?
6. Brain Imaging: What are the brain areas associated with different motion systems? How much information can we extract from brain imaging? How can we read people 抯 mind from their brain wave patterns?

Some of these questions have been answered in my publications; Some, and many others, are still under intensive investigation. To understand how the brain works, I believe we need to build models that are sufficiently computational (like the three-motion-systems model) that the actual computations can be represented in a computer program or mathematical theory. With such models, the search for >neurophysiological correlates will be most fruitful. Psychophysical experiments, physiological investigation, and mathematical plus computational modeling are all essential ingredients in understanding how the mind and brain operate.

Carlos Cabrera, Ph. D- Department of Psychology
Matriculated: August, 2002
Email: Carlos
Website:
Research Interest: My research uses psychophysical procedures to study features of decision processes: information degradation (representation and decision noise), response variability, biases, sequential dependence, and strategy selection. I am also interested in the development of efficient procedures to measure aspects of cognitive performance.

Lab Alumni

Rachel Beattie, Ph. D- Department of Psychology
Matriculated: July 2012
Email:
Website:
Research Interest: as a postdoctoral researcher for the Western Reserve Reading Project and the Laboratory of Brain Processes (LOBES), Rachel focuses to conduct neuroimaging studies to examine the development of the anatomical structures and functional processes underlying language, math, and reading skills. Prior to coming to Ohio State, Rachel received her Ph.D. in Psychology from the University of Southern California. Her other research projects have investigated: 1) low level perceptual deficits associated with dyslexia, 2) prosodic perception impairments in children with dyslexia and/or specific language impairment, and 3) early language skills necessary for beginning readers.

Changbing Huang, Ph.D. Department of Psychology
Matriculated:January 2007
Currently at: Institute of Psychology, Chinese Academy of Sciences
Telephone:
Email: Changbing
Website: http://vispal.psych.ac.cn/
Research Interest: I am currently focused on the computational mechanisms underlying perceptual learning. I am also very much interested in the physiological/psychophysical correlates of amblyopia, possible non-invasive treatments and the issue of brain plasticity that reflected by such processes.

Vision Center Laboratory (VCL-A), The Salk Institute for Biological Studies - La Jolla, CA

Department of Psychology, University of Southern California - Los Angeles
Department of Psychology, Loyola Marymount University - Los Angeles, CA

University of Rochester Medical Center - Rochester, NY

Department of Neurology , Georgetown University Medical Center - Washington D.C.