Intro
Transcranial magnetic stimulation is technology-based neuroengineering approach to treat addictive behaviors. In the most basic sense, the treatment involves generating an electromagnetic field that travels into the skull to excite or inhibit neurons. Since the treatment is relatively novel, the stimulation parameters (frequency, number of stimulation sessions) are still up for discussion and reform. However, in clinical settings, transcranial membrane stimulation has been used effectively to reduce cravings in people suffering from alcohol addiction.
Purpose
To diminish addictive behaviors, transcranial membrane stimulation targets dopamine receptors, since addiction damages dopamine transmission and function (context - long term alcohol abuse leads to excessive stimulation of dopamine neurons yielding a decrease in dopamine receptors). It is hypothesized that enhancing the production of dopamine (via stimulation of dopamine neurons) to achieve the appropriate amount of dopamine in the synaptic cleft will increase receptor count and thus diminish cravings. This is because the body will no longer crave substances as a means of restoring dopamine to an appropriate level.
Approach
Unfortunately, dopaminergic (dopamine-releasing) neurons are unreachable through direct stimulation, as they are located deep in the brain beyond the reach of current stimulation technology, so they must be reached indirectly.
A diagram tracing the path of indirect stimulation of dopamine-releasing neurons. Transcranial magnetic stimulation will stimulate the dorsolateral prefrontal cortex (DLPfcx) which will stimulate the ventral tegmental area (VTA) containing dopamine-releasing neurons (DA); the key idea here is to understand that indirect stimulation is a multi-step process (passing signal from start to checkpoint to end) as opposed to direct stimulation which involves a single step process (passing signal from start to end). Knowledge about the brain regions involved in TMS (DLPfcx & VTA) will not be elaborated on within this article, but can be read about online.
References
Diana, Marco. “The dopamine hypothesis of drug addiction and its potential therapeutic value.” Frontiers in psychiatry vol. 2 64. 29 Nov. 2011, doi:10.3389/fpsyt.2011.00064