Biomedical Engineering Reference
In-Depth Information
Like TMS, tDCS is being pursued in research and in the military for its ability to
enhance learning, memory, and other domains of cognitive function and as a poten-
tial treatment in various psychiatric conditions (Bullard et al. 2011; Brunelin et al.
2012). tDCS involves neurostimulation (or inhibition) by means of constant, low-
intensity current delivered directly to the brain area of interest through small elec-
trodes placed on either side of the scalp. It requires only small amounts of energy,
is portable, and is easy to administer. Even though the exact mechanisms by which
tDCS influences behavior are presently unknown, studies in humans are proceeding
and producing fascinating results (Bikson et al. 2009; Clark 2012).
For example, research sponsored by DARPA has discovered that tDCS has an
amazingly robust effect on learning. A 2012 study investigated whether tDCS would
increase the learning rate of identifying concealed objects placed in naturalistic sur-
roundings (Clark et al. 2012). Two levels of tDCS were applied, low current and high
current. The low-current tDCS resulted in a 10.5% increase in accuracy between
pretraining and delaying posttraining (one hour after training concluded), and high-
current tDCS resulted in a 21.3% increase in accuracy after delayed posttesting.
There was a 104% increase in overall performance accuracy between the non-tDCS
and tDCS groups, one of the largest effects reported in the learning literature (Clark
et al. 2012).
Additional studies have found tDCS to be significantly more effective when
applied to novice rather than experienced learners and that the effects of tDCS-
enhanced training will carry over into subsequent learning sessions (Bullard et al.
2011). Future work will investigate whether applying tDCS to different areas of the
brain at different stages of will maximize training effectiveness (Bullard et al. 2011).
The results to date suggest that the benefits of tDCS are significant in terms of edu-
cation and training. It would not only reduce the amount of time required to obtain
levels of expertise but could also result in individuals being able to acquire skills that
they may not have had the time (or the aptitude) to acquire before.
While the research continues, ethicists have begun to ask questions and consider
the implications of this work, including concerns regarding safety, justice, and auton-
omy, particularly as the technology migrates into widespread use in the commercial
and civilian sectors (Hamilton et al. 2011). From a national security perspective,
such remote mind scanning technologies may be seen as having many benefits, in
particular the more effective and less intrusive screening of airline passengers, pro-
spective intelligence agents, or suspected terrorists. While such applications have the
potential to be beneficial for national security, what would happen if (or more poi-
gnantly when) such technology becomes widely available? How will it affect police-
suspect, employer-employee, business-customer, spouse-spouse, parent-child, and
many other interactions? While there may be many benefits to some of the civilian
applications as well, such a technology would also have the potential for many dis-
ruptive and disconcerting consequences. The point being, should we not consider
those impacts before making a societal decision to develop such a technology?
A second example is behavior-modifying agents that can placate, calm, inca-
pacitate, or otherwise control individuals (National Research Council 2008; Royal
Society 2012). There is substantial evidence that militaries are investigating and
developing such behavior-altering agents, as evidenced by the Russian military's use
Search WWH ::
Custom Search