Tse studies where visual consciousness resides in the brain
Peter Tse, professor of psychological and brain sciences,
has published new results in his ongoing investigation of the brain and how it
transforms visual stimuli into conscious experience. His paper,
"Visibility, Visual Awareness, and Visual Masking of Simple Unattended
Targets are Confined to Areas in the Occipital Cortex Beyond Human V1/V2,"
was published in the November 8 issue of the weekly journal, The
Proceedings of the National Academy of Sciences. Tse's findings help to
explain what part of the brain is at work in turning sight into
understanding.
Peter Tse
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Tse, who is currently on sabbatical in Regensburg, Germany, as the recipient
of the prestigious Friedrich
Wilhelm Bessel Research Award, conducted experiments using the phenomenon
of "masking." Masking occurs when "a quickly flashed object
seems to vanish because it is flanked by subsequently presented objects,"
says Tse. Using Functional Magnetic Resonance Imaging (fMRI), Tse says he and
his team, "looked for areas of the brain where neuronal activity decreased
when the object was made invisible. These areas are arguably the areas of the
brain where the correlates of visual consciousness lie."
Tse's findings may advance the understanding of the brain's interaction with
the eye by identifying the neural basis of conscious experience, a relationship
important to the fields of medicine, neurology, and psychology.
Tse and his coauthors, Susana Martinez-Conde, Alexander A. Schlegel, and
Stephen L. Macknik of the Barrow
Neurological Institute, find that, "early areas in the visual
processing hierarchy respond the same whether or not objects are visible to us
or invisible in the context of visual masking." That is, some parts of the
brain respond to visual stimuli regardless of whether the conscious mind
"sees" them or not. However, Tse and his team found that,
"neural activity in areas beyond visual area 2 appear to correlate with
perception." They also found that the areas of the brain related to visual
perception appear to reside exclusively in the occipital lobe (at the back of
the head.) Tse's team concluded that, "the neural correlates of conscious
visual visibility for masking stimuli lie in the occipital lobe, but after
visual area 2."
By GENEVIEVE HAAS
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