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OBJECTIVE The cortical magnification factor characterizes the area of human primary visual cortex activated by a stimulus as a function of angular distance from an observer's line of sight. This study estimates human cortical magnification using an electrophysiological method with excellent temporal resolution: visual evoked potential (VEP) dipole source localization. METHODS For each of 60 independently modulated checkerboard patches within the central 18 deg of the visual field, location, orientation, magnitude, and time-course of the dipole current source that best described the VEP distribution across a multi-electrode array was obtained. At numerous eccentricities, cortical magnification was determined using two different techniques: (1) the distance between each pair of adjacent stimulus patches was matched to the corresponding distance between adjacent cortical sources; and (2) the area of each stimulus patch was matched to the magnitude of the corresponding cortical source (which was assumed to be proportional to cortical area). RESULTS The estimates of human cortical magnification using our electrophysiological method were similar to previous estimates from psychophysics, cortical stimulation, and functional magnetic resonance imaging. CONCLUSIONS The concordance of results provided by these disparate technologies, with differing spatial and temporal limitations, supports their combination in studying the spatio-temporal dynamics of human brain function.
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
January 1979,
Experimental brain research,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
June 2015,
Vision research,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
January 1974,
Experimental brain research,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
August 1987,
Journal of the Optical Society of America. A, Optics and image science,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
January 1983,
Perception,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
May 2003,
Neuron,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
January 1982,
Vision research,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
April 1998,
Vision research,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
January 1985,
Vision research,
S D Slotnick, and
S A Klein, and
T Carney, and
E E Sutter
December 2012,
Journal of mathematical neuroscience,
