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RECORD NUMBER: 110 OF 147

OLS Field Name OLS Field Data
Main Title Stationary Pattern Adaptation and the Early Components in Human Visual Evoked Potentials.
Author Hudnell, H. K. ; Boyes, W. K. ; Otto., D. A. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC. Neurotoxicology Div. ;North Carolina Univ. at Chapel Hill.
Publisher c1990
Year Published 1990
Report Number EPA/600/J-90/129;
Stock Number PB91-109686
Additional Subjects Pattern recognition ; Signal to noise ratio ; Humans ; Nerve cells ; Retina ; Spatial distribution ; Reprints ; Visual evoked potentials ; Physiological adaptation
Holdings
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Status
NTIS  PB91-109686 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 03/04/1991
Collation 12p
Abstract
Pattern-onset visual evoked potentials were elicited from humans by sinusoidal gratings of 0.5, 1, 2 and 4 cpd (cycles/degree) following adaptation to a blank field or one of the gratings. The wave forms recorded after blank field adaptation showed an early positive component, PO, which decreased in amplitude with spatial frequency, whereas the immediately succeeding negative component, N1, increased in amplitude with spatial frequency. PO and N1 components of comparable size were recorded at 1 cpd. Stationary pattern adaptation to a grating of the same spatial frequency as the test grating significantly reduced N1 amplitude at 4, 2 and 1 cpd. The N1 component elicited at 4 cpd was attenuated in log-linear fashion as the spatial frequency of the adaptation grating increased. PO, on the other hand, was unaffected by stationary pattern adaptation at all combinations of test and adapting spatial frequencies , although PO amplitude is known to be attenuated by adaptation to a drifting grating. Since N1, but not PO, was significantly attenuated following adaptation and testing at 1 cpd, it was concluded that the neurons generating these components are functionally distinct. The use of a common adaptation grating discounted the possibility that N1, but not PO, was affected due to a difference in the rates of retinal image modulation caused by eye movements made while viewing adaptation gratings of different spatial frequencies. The neurons generating N1 were adapted at a lower rate of retinal image modulation than that apparently required for adaptation of the neurons generating PO, which suggests a difference between these neurons in the rate of stimulus modulation necessary for activation. (Copyright (c) 1990 Elsevier Scientific Publishers Ireland, Ltd.)