Novel Future Brain Stimulation Technology
Researchers have upgraded the capacity of transcranial direct current stimulation (TDCS) to better serve patients with disorders. TDCS uses weak 1- 2 milliamp electric currents by way of electrodes attached to the head in order to influence brain activity. It causes a barely noticeable sensation for the patient. ECT by comparison needs over 500 milliamps to work and requires anesthesia. The lower amount of electricity has the capability of gently altering the voltage potential of the neuronal membranes. TDCS either increases or decreases neurons basal excitability in response to stimuli and is not as likely to cause a flurry of uncontrolled cell activity as with TMS. Neural functioning can either be enhanced or diminished in relatively select areas. This is basically taking advantage of neuroplastic mechanisms that are inherent to the brain. With repetitious parameters, the technique may induce longer lasting synaptic alterations by affecting glutamate signaling or perhaps other molecules (long term potentiation or long term depression). If used properly, it can speed up the rate at which the mind is able to acquire specific tasks or skills. Research using basic TDCS devices has been published in prestigious journals such as Nature. It has been shown to improve working memory and video game performance as just a few examples. The military is following recent developments with interest.
This new tDCS device has been developed by scientists at the neural engineering group. Instead of utilizing two electrodes like you would find with conventional tDCS, this is an entire cap that has many of them and is similar to an EEG. More regions of the brain can thus be adjusted than would normally be possible. You can hook this device up to a computer and allow it to deliver controlled stimulation to almost any region located close to a person’s skull. While it cannot directly touch deeper structures inside the brain, axons make many connections from one area to the next. This means it could potentially have a beneficial effect for disorders that are not normally associated with the cortex functioning. Perhaps stimulation parameters would eventually be very complex. A repeated pattern of kindling the visual cortex followed by the somatosensory cortex or the dorsolateral cortex may have some unknown properties that would exceed any single region by itself. TDCS has been used on people while they were sleeping to consolidate declarative memory. Perhaps it can even be utilized to study dreams. They are attempting to apply the technology for rehabilitation (see PDF)
It is easier to concurrently use fMRI and TDCS to gauge the changes in regional cerebral blood flow than with other types of neurotechnology (see PDF). Higher resolution delivered by new imaging devices may facilitate fresh insights into the mechanisms of action of TDCS. I think it seems possible that this could lead to a programmable brain that you would adjust with software. You might be able to download a specific program online that would change nervous system activity. There are a lot of crackpot ideas out there about synchronizing your brain waves. However this option at least offers a plausible way of actually influencing your thought processes.
While some doctors have serious doubts that it will find much use in the clinic, there seems to be many more potential avenues that have yet to be explored. So perhaps it is far too soon to be a neuro-skeptic about it. All kinds of everyday experiences change the electric fields inside the brain, so why not a more direct route?
See here for PDF presentation on TDCS. They mention deep TDCS, possibly through axonal connections.
