4 ms·

Very accurate summary! I would add * The current best guess is that the electrical stimulation inactivates the neurons (acting as a reversible lesion). Older s

by kghose 13y ago

Very accurate summary! I would add * The current best guess is that the electrical stimulation inactivates the neurons (acting as a reversible lesion). Older surgeries used to do a real lesion near that brain region. * Parkinson's is, unfortunately, a progressive disease. So the decrease in efficacy of the stimulation is partly related to the fact that this disease itself is getting worse. We typically hear that DBS buys a patient about another decade (which is a lot).

etrautmann 13y ago
I'd be very surprised if electrical stimulation simply acts as local inhibition. This is inconsistent with other electrical stimulation experiments (eg: driving muscle movements by stimulating in M1), and would not provide the correct manipulation to the basal ganglia. The problem in Parkinson's is that the Substantia Nigra and a certain class of excitatory neurons start dying off, leading to less dopamine release. The electrical stimulation is thought to stimulate the remaining neurons to release additional dopamine to compensate for this loss.
- refurb 13y ago
  Remember that the shaking you see in Parkinson's patients is not due to the disease, but that a side effect of the medication. Untreated Parkinson's patients "freeze".
- kghose 13y ago
  Yes, this is not clear (as far as I know). The direct effect of inserting current pulses is to excite neurons. However, this is followed by a period of inhibition. I am not sure of the cellular mechanisms. A reasonable review (with full text) is found here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2200868/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2200868/ The review details the suggestions that there are both excitatory and inhibitory effects of DBS. Another paper I know of is http://www.ncbi.nlm.nih.gov/pubmed/19864437 http://www.ncbi.nlm.nih.gov/pubmed/19864437 which goes into excitatory and inhibitory effects in cortex.

by kghose 13y ago

etrautmann 13y ago

I'd be very surprised if electrical stimulation simply acts as local inhibition. This is inconsistent with other electrical stimulation experiments (eg: driving muscle movements by stimulating in M1), and would not provide the correct manipulation to the basal ganglia. The problem in Parkinson's is that the Substantia Nigra and a certain class of excitatory neurons start dying off, leading to less dopamine release. The electrical stimulation is thought to stimulate the remaining neurons to release additional dopamine to compensate for this loss.

refurb 13y ago
Remember that the shaking you see in Parkinson's patients is not due to the disease, but that a side effect of the medication. Untreated Parkinson's patients "freeze".
kghose 13y ago
Yes, this is not clear (as far as I know). The direct effect of inserting current pulses is to excite neurons. However, this is followed by a period of inhibition. I am not sure of the cellular mechanisms. A reasonable review (with full text) is found here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2200868/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2200868/ The review details the suggestions that there are both excitatory and inhibitory effects of DBS. Another paper I know of is http://www.ncbi.nlm.nih.gov/pubmed/19864437 http://www.ncbi.nlm.nih.gov/pubmed/19864437 which goes into excitatory and inhibitory effects in cortex.