Premium
Visual evoked electrical and magnetic response to half‐field stimulation using pattern reversal stimulation
Author(s) -
Harding G. F. A.,
Armstrong R. A.,
Janday B.
Publication year - 1992
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.1992.tb00284.x
Subject(s) - gradiometer , visual cortex , stimulation , visual field , neuroscience , evoked potential , visual n1 , cortex (anatomy) , orientation (vector space) , nuclear magnetic resonance , magnetic field , occipital lobe , physics , psychology , visual perception , magnetometer , mathematics , geometry , quantum mechanics , perception
The visual evoked magnetic response to half‐field stimulation using pattern reversal was studied using a d.c. SQUID coupled to a second order gradiometer. The main component of the magnetic response consisted of a positive wave at around 100ms (P100M). At the lime this component was present the response to half‐field stimulation consisted of an outgoing magnetic field contralateral and extending lo the midline. When the left half Held was stimulated the outgoing field was over the posterior right visual cortex and when the right half field was stimulated it was over the left anterior visual cortex. These findings would correctly identify a source located in the contralateral visual cortex. The orientation of the dipoles was not that previously assumed to explain the paradoxical lateralization of the visual evoked potential. The results are discussed in terms of both electrical and magnetic models of the calcarine fissure.