Isolating components of electroconvulsive therapy

[Tribo]

By the form of electricity, would it be possible to change brain chemistry without using the procedures of ECT?

For instance, I would think in this day and age we could make a device that one would touch (like a doorknob) that could create a similar form of electroshock, only difference being it would travel up to the brain instead of away (reversing what happens in current ECT cases where the brain is electrocuted and the body convulses). The overall purpose would be to have a less intensive treatment option than the electrode-brain contact, perhaps even eliminating the need to create a seizure, and then in the name of sophistication raise the electric shock standard to that of greater accuracy and ease. Does this sound possible? And, if I wanted to evaluate the effects of such, where could I go?

Thanks!

 

[Drakkith]

Does this sound possible?

Not in the way you're imagining it. Electricity doesn't flow from the brain and into the muscles in the same way that it flows through a circuit. Electro-chemical impulses are what transfer commands from the brain to the muscles and those can't be reversed to "shock" the brain.

 

[Tribo]

"Electricity doesn't flow from the brain and into the muscles in the same way that it flows through a circuit."

Could you elaborate on that? Electro-chemical impulses start in the brain so it makes sense that they can't originate anywhere else... but the channel is still there so theoretically couldn't something travel up it? For instance, when someone is electrocuted their whole body is affected.

 

[Drakkith]

ould you elaborate on that? Electro-chemical impulses start in the brain so it makes sense that they can't originate anywhere else... but the channel is still there so theoretically couldn't something travel up it?

Nerve signals are sent by neurons as action potentials. The action potential starts near main body of the neuron and propagates down the axon, away from the main body, eventually ending at the axon terminal which is where the synapses are. The synapse itself (the junction where the axon terminal of one cell meets the dendrite of another cell) is mostly a one-way channel I believe. The axon terminal contains mostly transmitters and the dendrite contains mostly receptors. Because of these reasons, the ability for a signal to propagate backwards is very, very limited.

For instance, when someone is electrocuted their whole body is affected.

Not necessarily true. Electricity will preferentially flow along the paths of least resistance. Since an increase in path length usually leads to a larger resistance, the shortest paths between two terminals of a circuit usually carry the most current unless those paths are much higher in resistance than other paths. If you grab onto a faulty circuit with both hands, the shortest paths and the paths of least resistance are typically through each arm and your chest (and likely your heart), which is why being shocked in this way is so dangerous. The rest of your body is mostly unaffected. However, if you're wearing an insulated glove on one hand, the current could instead travel mostly through one arm, down your torso, and out through one or both legs and feet.

 

[Tribo]

Hmm... so do you think it's possible to create an ECT-like mechanism without attaching electrodes directly to the scalp?

 

[Drakkith]

Unlikely. You've got to provide a path for the electric current to flow to get from one electrode to the other that includes the brain. Since the brain is sitting at the extreme top of the body, you've got to connect the electrodes to the scalp, as there's no other way to set up that electrical path (unless you insert the electrodes into the brain I suppose).

 

[Tribo]

Nah that won't do, lol.

I will think on this some more then. Thank you for all your help!

 

[BillTre]

There are devices to do an approximation of this with magnetic rather than electrical pulses.
The magnetism drives voltage changes within neurons.

Both an external electrical stimulation or a magnetic one will have a pretty poor resolution (considering current technology), with respect to the functional units thought to exist in the cortex (outer brain layer). Cortical mini-cloumns (200-800 µm) and the 50-100 micro-columns they contain are much smaller then the areas these devices would affect. You might be able to exclusively hit some of the larger brain areas like visual cortex, but you might not be able to reach important deeper targets (like basal ganglia).
But because these techniques' non-invasive (non-surgical) nature is a great advantage.

A possible but (but not yet actual) approach is using multi photon excitation to optically drive a process (fluorescence, neural activity or neural activity reporter proteins) with infrared photons which penetrate tissue better than visible light.
Many photons in the same place at once, excite molecules (including proteins) in a semi-additive manner. This can drive fluorescence (two photon confocal microscopy), or in genetically programed organisms, it can effect neural activity (in cells making channel proteins open for certain ions when they adsorb light) or change fluorescence in response to neural activity (a protein becomes more fluorescent when intracellular Ca⁺⁺ goes up).
As far as I know, this has been done in labs only, under ideal research conditions. You don't run across many recombinant people yet.

A normally functioning nervous system runs on detailed .
These external shocking methods will work by setting off all the neurons in an area at once (not the normal way things work), except that bigger cells will be affected more strongly. The IR optical method should give good focus, but is an idea not yet realized.

 

[Pythagorean]

The axons themselves aren't one way, and neither are elctrical synapses, but chemicaal synapses (which is most long distance synapses) are one way and antidromic impulses will be stopped there.

 

[Laroxe]

There are several things that have and are being investigated, BillTre mentioned transcranial magnetic brain stimulation, which has been tried with a wide range of conditions. There is transcranial direct current stimulation, which has become popular as a cognitive enhancer and then vagus nerve stimulation, which may be the closest to what you suggest. There is plenty of information about these on the web, but so far the evidence of effectiveness, isn't very convincing.

 

[Tribo]

Came back to find more posts that have all blown my mind. Thanks. It's all very interesting stuff, but this is quickly becoming discouraging.

I was really interested in this topic from a psychological angle, as I was trying to figure out if I could make it into a research topic as a BA undergrad--I want to apply to graduate school and many that I'm looking at want to see research work with the application. I have none at the moment, so I thought I should figure out something to show them. Some stuff [edited out for digression] I was reading made me think of ECT and the physics behind it, but I'm still not sure of what I'm getting at. Not to sound dismissive of the information received thusfar, but I don't suppose there's any advice anyone could give?