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Behavioural Neurology
Volume 17 (2006), Issue 3-4, Pages 187-194
http://dx.doi.org/10.1155/2006/469132

Enhancement of Phonological Memory Following Transcranial Magnetic Stimulation (TMS)

Matthew P. Kirschen,1,2 Mathew S. Davis-Ratner,1 Thomas E. Jerde,1,2 Pam Schraedley-Desmond,1 and John E. Desmond3

1Department of Radiology, Stanford University, Stanford, CA 94305, USA
2Neurosciences Program, Stanford University, Stanford, CA 94305, USA
3Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA

Received 21 November 2006; Accepted 21 November 2006

Copyright © 2006 Hindawi Publishing Corporation and the authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Phonologically similar items (mell, rell, gell) are more difficult to remember than dissimilar items (shen, floy, stap), likely because of mutual interference of the items in the phonological store. Low-frequency transcranial magnetic stimulation (TMS), guided by functional magnetic resonance imaging (fMRI) was used to disrupt this phonological confusion by stimulation of the left inferior parietal (LIP) lobule. Subjects received TMS or placebo stimulation while remembering sets of phonologically similar or dissimilar pseudo-words. Consistent with behavioral performance of patients with neurological damage, memory for phonologically similar, but not dissimilar, items was enhanced following TMS relative to placebo stimulation. Stimulation of a control region of the brain did not produce any changes in memory performance. These results provide new insights into how the brain processes verbal information by establishing the necessity of the inferior parietal region for optimal phonological storage. A mechanism is proposed for how TMS reduces phonological confusion and leads to facilitation of phonological memory.