Visual stimuli induce waves of electrical activity in turtle cortex

Prechtl, J. C., Cohen, L. B., Pesaran, B., Mitra, P. P., Kleinfeld, D. (1997) Visual stimuli induce waves of electrical activity in turtle cortex. Proceedings of the National Academy of Sciences of the United States of America, 94 (14). pp. 7621-7626. ISSN 00278424 (ISSN)

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DOI: 10.1073/pnas.94.14.7621


The computations involved in the processing of a visual scene invariably involve the interactions among neurons throughout all of visual cortex. One hypothesis is that the timing of neuronal activity, as well as the amplitude of activity, provides a means to encode features of objects. The experimental data from studies on cat [Gray, C. M., Konig, P., Engel, A. K. and Singer, W. (1989) Nature (London) 338,334-337] support a view in which only synchronous (no phase lags) activity carries information about the visual scene. In contrast, theoretical studies suggest, on the one hand, the utility of multiple phases within a population of neurons as a means to encode independent visual features and, on the other hand, the likely existence of timing differences solely on the basis of network dynamics. Here we use widefield imaging in conjunction with voltage-sensitive dyes to record electrical activity from the virtually intact, unanesthetized turtle brain. Our data consist of single-trial measurements. We analyze our data in the frequency domain to isolate coherent events that lie in different frequency bands. Low frequency oscillations (<5 Hz) are seen in both ongoing activity and activity induced by visual stimuli. These oscillations propagate parallel to the afferent input. Higher frequency activity, with spectral peaks near 10 and 20 Hz, is seen solely in response to stimulation. This activity consists of plane waves and spiral-like waves, as well as more complex patterns. The plane waves have an average phase gradient of ≃π/2 radians/mm and propagate orthogonally to the low frequency waves. Our results show that large-scale differences in neuronal timing are present and persistent during visual processing.

Item Type: Paper
Uncontrolled Keywords: animal tissue article brain cortex brain electrophysiology female imaging male nonhuman priority journal turtle visual stimulation Animals Cats Cerebral Cortex Electrophysiology Photic Stimulation Phototransduction Turtles Animalia Felis catus Testudines
Subjects: physics > biophysics
organs, tissues, organelles, cell types and functions > tissues types and functions > cerebral cortex
organism description > animal behavior > vision
organs, tissues, organelles, cell types and functions > tissues types and functions > visual cortex
CSHL Authors:
Communities: CSHL labs > Mitra lab
Depositing User: CSHL Librarian
Date: 1997
Date Deposited: 02 Apr 2012 20:15
Last Modified: 11 Sep 2019 17:01
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