Re: transcranial magnetic stimulation (was Uploading and Nanotech)

Anders Sandberg (
19 Apr 1998 13:48:22 +0200

Holger Wagner <> writes:

> Is that paper available on the internet? I'd be especially interested in
> how much "fine-tuning" is possible to stimulate smaller and smaller
> parts or even complex patterns.

Unlikely, Nature doesn't seem to have full text articles on the
net. But the article I was refering to can likely be found at a

author = {L. G. Cohen and P. Celnik and A. Pascual-Leone and B. Corwell and L. Falz and J. Dambrosia and M. Honda and N. Sadato and C. Gerloff and M. D. Catala and M. Hallett},
title = {Functional relevance of cross-modal plasticity in blind humans},
journal = {Nature},
volume = {389},
number = {6647},
pages = {180--3},
month = {Sep 11},
year = {1997},
keywords = {Adult *Blindness Evoked Potentials, Somatosensory Female Human Magnetics Male Middle Age *Neuronal Plasticity Occipital Lobe/physiology Reading Sensory Aids Touch/*physiology Visual Cortex/*physiology Visual Pathways/physiology},
abstract = {Functional imaging studies of people who were blind
from an early age have revealed that their primary visual cortex can
be activated by Braille reading and other tactile discrimination
tasks. Other studies have also shown that visual cortical areas can be
activated by somatosensory input in blind subjects but not those with
sight. The significance of this cross-modal plasticity is unclear,
however, as it is not known whether the visual cortex can process
somatosensory information in a functionally relevant way. To address
this issue, we used transcranial magnetic stimulation to disrupt the
function of different cortical areas in people who were blind from an
early age as they identified Braille or embossed Roman
letters. Transient stimulation of the occipital (visual) cortex
induced errors in both tasks and distorted the tactile perceptions of
blind subjects. In contrast, occipital stimulation had no effect on
tactile performance in normal-sighted subjects, whereas similar
stimulation is known to disrupt their visual performance. We conclude
that blindness from an early age can cause the visual cortex to be
recruited to a role in somatosensory processing. We propose that this
cross-modal plasticity may account in part for the superior tactile
perceptual abilities of blind subjects.} }

Anders Sandberg                                      Towards Ascension!                  
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y