An integrative transcranial magnetic stimulation mapping technique using non-linear curve fitting

Kohl, Alexandra S; Conforto, Adriana Bastos; Z'Graggen, Werner J; Kaelin-Lang, Alain (2006). An integrative transcranial magnetic stimulation mapping technique using non-linear curve fitting. Journal of neuroscience methods, 157(2), pp. 278-84. Amsterdam: Elsevier 10.1016/j.jneumeth.2006.04.018

Full text not available from this repository. (Request a copy)

The aim of this study is to develop a new simple method for analyzing one-dimensional transcranial magnetic stimulation (TMS) mapping studies in humans. Motor evoked potentials (MEP) were recorded from the abductor pollicis brevis (APB) muscle during stimulation at nine different positions on the scalp along a line passing through the APB hot spot and the vertex. Non-linear curve fitting according to the Levenberg-Marquardt algorithm was performed on the averaged amplitude values obtained at all points to find the best-fitting symmetrical and asymmetrical peak functions. Several peak functions could be fitted to the experimental data. Across all subjects, a symmetric, bell-shaped curve, the complementary error function (erfc) gave the best results. This function is characterized by three parameters giving its amplitude, position, and width. None of the mathematical functions tested with less or more than three parameters fitted better. The amplitude and position parameters of the erfc were highly correlated with the amplitude at the hot spot and with the location of the center of gravity of the TMS curve. In conclusion, non-linear curve fitting is an accurate method for the mathematical characterization of one-dimensional TMS curves. This is the first method that provides information on amplitude, position and width simultaneously.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology

UniBE Contributor:

Z'Graggen, Werner Josef and Kaelin, Alain










Factscience Import

Date Deposited:

04 Oct 2013 14:46

Last Modified:

06 Dec 2013 13:41

Publisher DOI:


PubMed ID:


Web of Science ID:


URI: (FactScience: 1480)

Actions (login required)

Edit item Edit item
Provide Feedback