Dr. Michael W. Levine
Office: 1042B
Phone (312)-996-6133
E-Mail to MikeL@UIC.EDU
Vision Sciences Society presentations (pdf versions)
Information about the current edition of Fundamentals of Sensation and Perception
Upgrade for the SensPerc program on the CD in the book
Go Back to UIC Michael Levine Page.
My research is in visual processing. After many years studying retinal processing, I have now turned my attention to higher-level visual processing in the human brain.
My current work concentrates on the capabilities of the various visual pathways or channels that process visual information. The dorsal stream seems to be concerned with position of objects, probably to provide direct control of visually guided movements within the near space (i.e.: hand-eye coordination). The ventral stream seems to be the source of the fine discriminations that enable us to recognize objects; that is, it is the gateway to cognitive awareness.
But there are other distinctions. The dorsal stream is dominated (but certainly not exclusively) by input from the magnocellular system, a collection of cells that respond best to rapid changes in time. The ventral stream is dominated by the parvocellular system, which is better at discriminating subtle changes in size, hue, or lightness. There also are differences in the capabilities of the various pathways for stimuli displaced above or below the point of central gaze. These differences presumably have ecological significance, and may serve to reveal the contributions and workings of the various pathways.
Recent work includes psychophysical examinations of a phenomenon we refer to as "blanking" -- a visual illusion based on the scintillating grid in which a normally clear stimulus can be rendered completely invisible. This project is being spearheaded by Jason McAnany, a graduate student in my lab. This work has been presented at the VSS meeting in May, 2002; paper. A refinement that examines the roles of central and peripheral processing was presented at VSS 2003. We are now embarking on an fMRI study to determine the brain mechanisms of the phenomenon.
One of the interesting observations to
come from the blanking studies is that the effect is stronger in the upper
visual field. We have been exploring the differences between upper and lower
fields, and found that which field is better at a task depends on the nature of
the task. Specifically, color is better processes in the lower visual field,
but apparent depth in the upper field. Preliminary results were presented at VSS 2004; paper. These studies are ongoing. Examinations of the magno- and parvo-cellular
contributions to these effects (McAnany
& Levine), and the spatial frequency dependencies of the effects (Levine & McAnany) was presented at VSS 2005.
Another aspect to which I have devoted
considerable attention in the past is the variability of the visual signal. The
firing that presumably carries visual information is unsteady and stochastic.
It is possible that this variability can provide a window into the processing
by which it is combined with the deterministic signal. There also is the
question of why we see so clearly given this noisy input; this raises the
tantalizing possibility that the "noise" is actually an indispensable
part of the process by which we interpret the visual stimulus; paper.
A more recent study of the transmission at the thalamus appeared in Brain
Research. Recent paper. In the future, I hope to extend the psychophysical studies
to include the effects of variability (noise) on the processing in the various
pathways.
Recent papers
An analysis of the effect of retinal ganglion cell impulses upon the firing probability of neurons in the dorsal lateral geniculate nucleus of the cat. Michael W. Levine & Brian G. Cleland. (2001) Brain Research 902: 244-254. view Abstract
Firing coincidences between neighboring retinal ganglion cells: inside information or epiphenomenon? Michael W. Levine, Kristen Castaldo, & M. Baris Kasapoglu. (2002) Biosystems 67: 139-146. view Abstract
The potential coding utility
of intercell cross-correlations in the retina. Michael W. Levine. Biological Cybernetics 91; 182-187.
Online at: Springer
publishing on-line. view Abstract
The blanking phenomenon and its psychoanatomical implications. J. Jason McAnany, and Michael W. Levine. (2004). Vision Research 44; 993-1001. PDF version (proofs).
A psychoanatomical investigation of the blanking phenomenon. J. Jason McAnany, and Michael W. Levine. (2005). Vision Research. 45; 193-203. See manuscript.
The relative capabilities of the upper and
lower visual hemifields.
Michael W. Levine
and J. Jason McAnany.
(2005). Vision Research. 45; 2820-2830.
[Online at www.sciencedirect.com]. See manuscript
Sensation.
Michael. W. Levine. McGraw-Hill Encyclopedia of Science & Technology,
10th edition (in press) On line: DOI
10.1036/1097-8542.614600
Spectral characteristics of period doubling in the cone flicker electroretinogram. Kenneth. R. Alexander, Michael. W. Levine, and Boaz Super (2005). Visual Neuroscience 22; 817-824.
Variability in the firing of retinal
ganglion cells of goldfish: A review. Michael W. Levine. (2007). Visual Neuroscience 24; 239-246. PDF version
Magnocellular and parvocellular
visual pathway contributions to visual field anisotropies. J. Jason McAnany, and Michael W. Levine. (2007). Vision Research 47; 2327-2336. PDF version
(proofs)
The effects of curvature on
the grid illusions. Michael W. Levine and J. Jason McAnany.
Perception (in press) See manuscript
VSS 2002 The vanishing disk; a revealing quirk of the
scintillating grid illusion J. J. McAnany
& M. W. Levine
VSS 2003 The Blanking Phenomenon and its Psychoanatomical Implications J. J. McAnany & M. W. Levine
VSS 2004 The highs and lows of magnocellular and parvocellular processing J. Jason McAnany & Michael W. Levine
VSS 2005a Magnocellular- and parvocellular-pathway contributions to a novel visual illusion J. J. McAnany & M. W. Levine
VSS 2005b More ups and downs of visual processing M. W. Levine & J. J. McAnany
VSS 2006a The role of magnocellular
and parvocellular visual pathways in altitudinal
visual hemifield anisotropies J. Jason McAnany & Michael W.
Levine
VSS 2006b A new twist to the grid
illusions Michael W Levine & J. Jason McAnany
VSS 2008a The effect of curvature on the
grid illusions: Influence of a homunculus? Michael
W Levine, J. Jason McAnany, & Jennifer E.
Anderson
VSS 2008b Prestidigitation: Is it
easier to fool the eye than the hand? Jennifer
E. Anderson, Michael W Levine, & J. Jason McAnany
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