john herr psychologist los gatos saratoga california

On Sabbatical

Psychiatric Neuroimaging Group


Transcranial magnetic stimulation (TMS)

TMS is a technique in which a small transient electrical current in the cerebral cortex is induced by a very strong magnetic field created by a stimulating coil. The stimulating coil is held close to the scalp so that the field is focused and can pass through the skull. The magnetic field produces local electrical currents in tissue. Repetitive transcranial magnetic stimulation (rTMS) is a new and powerful refinement of TMS by which the magnetic field can be repeated over small intervals of time, thus allowing the stimulation of neurons during their refractory period.

There has been recent interest in whether rTMS might have antidepressant actions if applied to the proper cortical regions and with the appropriate dosing and frequency parameters. PNIG has been funded by the Swiss National Science Foundation to conduct a series of in-depth studies designed to assess the effects of rTMS on mood in patients suffering from treatment refractory major depression. As part of the series of studies, PNIG will use rTMS in conjunction with neuroimaging techniques (e.g., PET, SPECT, fMRI) to elucidate how rTMS affects the functional neuroanatomy of depressed patients following successful treatment with rTMS.

A layman's introduction to TMS

A collection of TMS graphs and diagrams

University of Tasmania's TMS Info site

Helsinki University's TMS site

TMS mailing list

TMS conference

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This page was created Tuesday, November 12, 1996, and was last modified Saturday, November 27, 1999.

On Sabbatical!

When my office lease expired at the end of 2004, I decided to turn it into a "sabbatical" from my private practice. Many years ago, in my grandfather's 89th year of life, he told me, "John, it is important to smell the roses while you can still smell them." His life gave living a very good reputation. It is also true that the pursuit of that philosophy required my grandfather to to re-open his assay office/ore market in Wickenburg, Arizona as a 75-year-old because he had run a little short of retirement money. Thus, if blessed with his luck and health, I'll be back.. --jjh

Copyright 1998-2007  John J. Herr, Ph.D.                                   Please send comments to