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Suppression of perceptual accuracy in migraineurs: a transcranial magnetic stimulation study of visual cortex excitability.

Mulleners, Wim M. and Chronicle, E. P. and Palmer, J. E. and Koehler, P. J. and Vredeveld, J. W. (2001) Suppression of perceptual accuracy in migraineurs: a transcranial magnetic stimulation study of visual cortex excitability. Neurology, 56 (2). pp. 178-183. ISSN 0028-3878

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Abstract

BACKGROUND: Results from transcranial magnetic stimulation (TMS) studies of visual cortex have confirmed visual cortical hyperexcitability in patients with migraine. It has been speculated that this may be due to deficient intracortical inhibitory tone. However, the TMS induction of phosphenes relies on the reporting of a subjective experience, and may thus be subject to bias. METHODS: Seven migraineurs with visual aura and seven sex- and age-matched controls were studied. Fifty-four different three-letter combinations were briefly displayed and followed by a magnetic pulse at 40, 70, 100, 130, 160, and 190 msec. Subjects were required to report as many letters as they thought they had recognized. RESULTS: In the migraine group, the mean proportion of correctly identified letters was significantly higher at 100 msec, as was the proportion of trials with two or three letters correctly reported. The time window in which perceptual suppression could be introduced was narrower in migraineurs compared to controls. CONCLUSION: These findings suggest that inhibitory systems are activated to a lesser extent by TMS pulses in patients. This observation is in agreement with the hypothesized deficiency of intracortical inhibition of the visual cortex, at least in migraineurs with aura.

Item Type: Article
Journal or Publication Title: Neurology
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Departments: Faculty of Science and Technology > Psychology
Faculty of Science and Technology > Physics
ID Code: 18827
Deposited By: ep_ss_importer
Deposited On: 04 Nov 2008 13:46
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:22
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/18827

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